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  • 51.
    Ambarki, Khalid
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Centrum för medicinsk teknik och fysik (CMTF).
    Wåhlin, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Zarrinkoob, Laleh
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Wirestam, R.
    Petr, J.
    Malm, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Eklund, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Centrum för medicinsk teknik och fysik (CMTF). Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI).
    Accuracy of Parenchymal Cerebral Blood Flow Measurements Using Pseudocontinuous Arterial Spin-Labeling in Healthy Volunteers2015Inngår i: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 36, nr 10, s. 1816-1821Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND AND PURPOSE: The arterial spin-labeling method for CBF assessment is widely available, but its accuracy is not fully established. We investigated the accuracy of a whole-brain arterial spin-labeling technique for assessing the mean parenchymal CBF and the effect of aging in healthy volunteers. Phase-contrast MR imaging was used as the reference method. MATERIALS AND METHODS: Ninety-two healthy volunteers were included: 49 young (age range, 20-30 years) and 43 elderly (age range, 65-80 years). Arterial spin-labeling parenchymal CBF values were averaged over the whole brain to quantify the mean pCBF(ASL) value. Total. CBF was assessed with phase-contrast MR imaging as the sum of flows in the internal carotid and vertebral arteries, and subsequent division by brain volume returned the pCBF(PCMRI) value. Accuracy was considered as good as that of the reference method if the systematic difference was less than 5 mL/min/100 g of brain tissue and if the 95% confidence intervals were equal to or better than +/- 10 mL/min/100 g. RESULTS: pCBF(ASL) correlated to pCBF(PCMRI) (r = 0.73; P < .001). Significant differences were observed between the pCBF(ASL) and pCBF(PCMRI) values in the young (P = .001) and the elderly (P < .001) volunteers. The systematic differences (mean 2 standard deviations) were -4 +/- 14 mL/min/100 g in the young subjects and 6 +/- 12 mL/min/100 g in the elderly subjects. Young subjects showed higher values than the elderly subjects for pCBF(PCMRI) (young, 57 +/- 8 mL/min/100 g; elderly, 54 +/- 7 mL/min/100 g; P = .05) and pCBF(ASL) (young, 61 +/- 10 mL/min/100 g; elderly, 48 +/- 10 mL/min/100 g; P < .001). CONCLUSIONS: The limits of agreement were too wide for the arterial spin-labeling method to be considered satisfactorily accurate, whereas the systematic overestimation in the young subjects and underestimation in the elderly subjects were close to acceptable. The age-related decrease in parenchymal CBF was augmented in arterial spin-labeling compared with phase-contrast MR imaging.

  • 52. Amirian, E. Susan
    et al.
    Armstrong, Georgina N.
    Zhou, Renke
    Lau, Ching C.
    Claus, Elizabeth B.
    Barnholtz-Sloan, Jill S.
    Il'yasova, Dora
    Schildkraut, Joellen
    Ali-Osman, Francis
    Sadetzki, Siegal
    Johansen, Christoffer
    Houlston, Richard S.
    Jenkins, Robert B.
    Lachance, Daniel
    Olson, Sara H.
    Bernstein, Jonine L.
    Merrell, Ryan T.
    Wrensch, Margaret R.
    Davis, Faith G.
    Lai, Rose
    Shete, Sanjay
    Amos, Christopher I.
    Scheurer, Michael E.
    Aldape, Kenneth
    Alafuzoff, Irina
    Brännström, Thomas
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap.
    Broholm, Helle
    Collins, Peter
    Giannini, Caterina
    Rosenblum, Marc
    Tihan, Tarik
    Melin, Beatrice S.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Bondy, Melissa L.
    The Glioma International Case-Control Study: A Report From the Genetic Epidemiology of Glioma International Consortium2016Inngår i: American Journal of Epidemiology, ISSN 0002-9262, E-ISSN 1476-6256, Vol. 183, nr 2, s. 85-91Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Decades of research have established only a few etiological factors for glioma, which is a rare and highly fatal brain cancer. Common methodological challenges among glioma studies include small sample sizes, heterogeneity of tumor subtypes, and retrospective exposure assessment. Here, we briefly describe the Glioma International Case-Control (GICC) Study (recruitment, 2010-2013), a study being conducted by the Genetic Epidemiology of Glioma International Consortium that integrates data from multiple data collection sites, uses a common protocol and questionnaire, and includes biospecimen collection. To our knowledge, the GICC Study is the largest glioma study to date that includes collection of blood samples, which will allow for genetic analysis and interrogation of gene-environment interactions.

  • 53. Amirian, E. Susan
    et al.
    Armstrong, Georgina
    Zhou, Renke
    Wrensch, Margaret
    Olson, Sara
    Scheurer, Michael
    Il'yasova, Dora
    Lachance, Daniel
    Lau, Ching
    Claus, Elizabeth
    Barnholtz-Sloan, Jill
    Schildkraut, Joellen
    Ali-Osman, Francis
    Sadetzki, Siegal
    Johansen, Christoffer
    Houlston, Richard
    Jenkins, Robert
    Bernstein, Jonine
    Merrell, Ryan
    Davis, Faith
    Lai, Rose
    Shete, Sanjay
    Amos, Christopher
    Melin, Beatrice
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Bondy, Melissa
    DEMOGRAPHICS AND LIFESTYLE FACTORS IN GLIOMA RISK: A REPORT FROM THE GLIOMA INTERNATIONAL CASE-CONTROL STUDY2016Inngår i: Neuro-Oncology, ISSN 1522-8517, E-ISSN 1523-5866, Vol. 18, s. 57-58Artikkel i tidsskrift (Fagfellevurdert)
  • 54. Amirian, E. Susan
    et al.
    Ostrom, Quinn T.
    Armstrong, Georgina N.
    Lai, Rose K.
    Gu, Xiangjun
    Jacobs, Daniel I.
    Jalali, Ali
    Claus, Elizabeth B.
    Barnholtz-Sloan, Jill S.
    Il'yasova, Dora
    Schildkraut, Joellen M.
    Ali-Osman, Francis
    Sadetzki, Siegal
    Jenkins, Robert B.
    Lachance, Daniel H.
    Olson, Sara H.
    Bernstein, Jonine L.
    Merrell, Ryan T.
    Wrensch, Margaret R.
    Johansen, Christoffer
    Houlston, Richard S.
    Scheurer, Michael E.
    Shete, Sanjay
    Amos, Christopher I.
    Melin, Beatrice S.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Bondy, Melissa L.
    Aspirin, NSAIDs, and Glioma Risk: Original Data from the Glioma International Case-Control Study and a Meta-analysis2019Inngår i: Cancer Epidemiology, Biomarkers and Prevention, ISSN 1055-9965, E-ISSN 1538-7755, Vol. 28, nr 3, s. 555-562Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: There have been few studies of sufficient size to address the relationship between glioma risk and the use of aspirin or NSAIDs, and results have been conflicting. The purpose of this study was to examine the associations between glioma and aspirin/NSAID use, and to aggregate these findings with prior published studies using meta-analysis. Methods: The Glioma International Case-Control Study (GICC) consists of 4,533 glioma cases and 4,171 controls recruited from 2010 to 2013. Interviews were conducted using a standardized questionnaire to obtain information on aspirin/NSAID use. We examined history of regular use for >= 6 months and duration-response. Restricted maximum likelihood meta-regression models were used to aggregate site-specific estimates, and to combine GICC estimates with previously published studies. Results: A history of daily aspirin use for -6 months was associated with a 38% lower glioma risk, compared with not having a history of daily use [adjusted meta-OR = 0.62; 95% confidence interval (CI), 0.54-0.70]. There was a significant duration-response trend (P = 1.67 -10 -17), with lower ORs for increasing duration of aspirin use. Duration-response trends were not observed for NSAID use. In the meta-analysis aggregating GICC data with five previous studies, there was a marginally significant association between use of aspirin and glioma (mOR = 0.84; 95% CI, 0.70-1.02), but no association for NSAID use. Conclusions: Our study suggests that aspirin may be associated with a reduced risk of glioma. Impact: These results imply that aspirin use may be associated with decreased gliomarisk. Further research examining the association between aspirin use and glioma risk is warranted.

  • 55. Amirian, E. Susan
    et al.
    Scheurer, Michael E.
    Wrensch, Margaret
    Olson, Sara H.
    Lai, Rose
    Lachance, Daniel
    Armstrong, Georgina
    Zhou, Renke
    Wiemels, Joseph
    Lau, Ching
    Claus, Elizabeth
    Barnholtz-Sloan, Jill
    Il'yasova, Dora
    Schildkraut, Joellen
    Houlston, Richard
    Shete, Sanjay
    Bernstein, Jonine
    Jenkins, Robert
    Davis, Faith
    Merrell, Ryan
    Johansen, Christoffer
    Sadetzki, Siegal
    Melin, Beatrice
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Bondy, Melissa
    ATOPIC CONDITIONS, ANTIHISTAMINE USE, AND GLIOMA RISK: PRELIMINARY RESULTS FROM THE GLIOMA INTERNATIONAL CASE-CONTROL STUDY2013Inngår i: Neuro-Oncology, ISSN 1522-8517, E-ISSN 1523-5866, Vol. 15, nr Supplement: 3, s. 32-32Artikkel i tidsskrift (Annet vitenskapelig)
  • 56. Amirian, E. Susan
    et al.
    Scheurer, Michael E.
    Zhou, Renke
    Wrensch, Margaret R.
    Armstrong, Georgina N.
    Lachance, Daniel
    Olson, Sara H.
    Lau, Ching C.
    Claus, Elizabeth B.
    Barnholtz-Sloan, Jill S.
    Il'yasova, Dora
    Schildkraut, Joellen
    Ali-Osman, Francis
    Sadetzki, Siegal
    Jenkins, Robert B.
    Bernstein, Jonine L.
    Merrell, Ryan T.
    Davis, Faith G.
    Lai, Rose
    Shete, Sanjay
    Amos, Christopher I.
    Melin, Beatrice S.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Bondy, Melissa L.
    History of chickenpox in glioma risk: a report from the glioma international case-control study (GICC)2016Inngår i: Cancer Medicine, ISSN 2045-7634, E-ISSN 2045-7634, Vol. 5, nr 6, s. 1352-1358Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Varicella zoster virus (VZV) is a neurotropic alpha-herpesvirus that causes chickenpox and establishes life-long latency in the cranial nerve and dorsal root ganglia of the host. To date, VZV is the only virus consistently reported to have an inverse association with glioma. The Glioma International Case-Control Study (GICC) is a large, multisite consortium with data on 4533 cases and 4171 controls collected across five countries. Here, we utilized the GICC data to confirm the previously reported associations between history of chickenpox and glioma risk in one of the largest studies to date on this topic. Using two-stage random-effects restricted maximum likelihood modeling, we found that a positive history of chickenpox was associated with a 21% lower glioma risk, adjusting for age and sex (95% confidence intervals (CI): 0.65-0.96). Furthermore, the protective effect of chickenpox was stronger for high-grade gliomas. Our study provides additional evidence that the observed protective effect of chickenpox against glioma is unlikely to be coincidental. Future studies, including meta-analyses of the literature and investigations of the potential biological mechanism, are warranted.

  • 57. Amirian, E. Susan
    et al.
    Zhou, Renke
    Wrensch, Margaret R.
    Olson, Sara H.
    Scheurer, Michael E.
    Il'yasova, Dora
    Lachance, Daniel
    Armstrong, Georgina N.
    McCoy, Lucie S.
    Lau, Ching C.
    Claus, Elizabeth B.
    Barnholtz-Sloan, Jill S.
    Schildkraut, Joellen
    Ali-Osman, Francis
    Sadetzki, Siegal
    Johansen, Christoffer
    Houlston, Richard S.
    Jenkins, Robert B.
    Bernstein, Jonine L.
    Merrell, Ryan T.
    Davis, Faith G.
    Lai, Rose
    Shete, Sanjay
    Amos, Christopher I.
    Melin, Beatrice S.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Bondy, Melissa L.
    Approaching a Scientific Consensus on the Association between Allergies and Glioma Risk: a report from the Glioma International Case-Control Study2016Inngår i: Cancer Epidemiology, Biomarkers and Prevention, ISSN 1055-9965, E-ISSN 1538-7755, Vol. 25, nr 2, s. 282-290Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: Several previous studies have found inverse associations between glioma susceptibility and a history of allergies or other atopic conditions. Some evidence indicates that respiratory allergies are likely to be particularly relevant with regard to glioma risk. Using data from the Glioma International Case-Control Study (GICC), we examined the effects of respiratory allergies and other atopic conditions on glioma risk. Methods: The GICC contains detailed information on history of atopic conditions for 4,533 cases and 4,171 controls, recruited from 14 study sites across five countries. Using two-stage random-effects restricted maximum likelihood modeling to calculate meta-analysis ORs, we examined the associations between glioma and allergy status, respiratory allergy status, asthma, and eczema. Results: Having a history of respiratory allergies was associated with an approximately 30% lower glioma risk, compared with not having respiratory allergies (mOR, 0.72; 95% confidence interval, 0.58-0.90). This association was similar when restricting to high-grade glioma cases. Asthma and eczema were also significantly protective against glioma. Conclusion: A substantial amount of data on the inverse association between atopic conditions and glioma has accumulated, and findings from the GICC study further strengthen the existing evidence that the relationship between atopy and glioma is unlikely to be coincidental. Impact: As the literature approaches a consensus on the impact of allergies in glioma risk, future research can begin to shift focus to what the underlying biologic mechanism behind this association may be, which could, in turn, yield new opportunities for immunotherapy or cancer prevention. (C) 2016 AACR.

  • 58. Amundadottir, Laufey T
    et al.
    Sulem, Patrick
    Gudmundsson, Julius
    Helgasson, Agnar
    Baker, Adam
    Agnarsson, Bjarni A
    Sigurdsson, Asgeir
    Benediktsdottir, Kristrun R
    Cazier, Jean-Baptiste
    Sainz, Jesus
    Jakobsdottir, Margret
    Kostic, Jelena
    Magnusdottir, Droplaug N
    Gosh, Shyamali
    Agnarsson, Kari
    Birgisdottir, Birgitta
    Le Roux, Louise
    Olafsdottir, Adalheidur
    Blondal, Thorarinn
    Andresdottir, Margret
    Gretarsdottir, Olafia Svandis
    Bergthorsson, Jon T
    Gudbjartsson, Daniel
    Gylfason, Arnaldur
    Thorleifsson, Gudmar
    Manolescu, Andrei
    Kristjansson, Kristleifur
    Geirsson, Gudmundur
    Isaksson, Helgi
    Douglas, Julie
    Johansson, Jan-Erik
    Bälter, Katarina
    Wiklund, Fredrik
    Montie, James E
    Yu, Xiaoying
    Suarez, Brian K
    Ober, Carole
    Cooney, Kathleen A
    Grönberg, Henrik
    Umeå universitet, Medicinsk fakultet, Strålningsvetenskaper.
    Catalona, William J
    Einarsson, Gudmundur V
    Barkardottir, Rosa B
    Gulcher, Jeffrey R
    Kong, Augustine
    Thorsteinsdottir, Unnur
    Stefansson, Kari
    A common variant associated with prostate cancer in European and African populations2006Inngår i: Nature Genetics, Vol. 38, nr 6, s. 652-658Artikkel i tidsskrift (Fagfellevurdert)
  • 59. Anantharaman, Devasena
    et al.
    Gheit, Tarik
    Waterboer, Tim
    Halec, Gordana
    Carreira, Christine
    Abedi-Ardekani, Behnoush
    McKay-Chopin, Sandrine
    Zaridze, David
    Mukeria, Anush
    Szeszenia-Dabrowska, Neonila
    Lissowska, Jolanta
    Mates, Dana
    Janout, Vladimir
    Foretova, Lenka
    Bencko, Vladimir
    Rudnai, Peter
    Fabianova, Eleonora
    Tjonneland, Anne
    Travis, Ruth C
    Boeing, Heiner
    Quiros, J Ramon
    Johansson, Mikael
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Krogh, Vittorio
    Bueno-de-Mesquita, H Bas
    Kotanidou, Anastasia
    Clavel-Chapelon, Francoise
    Weiderpass, Elisabete
    Johansson, Mattias
    Pawlita, Michael
    Scelo, Ghislaine
    Tommasino, Massimo
    Brennan, Paul
    No causal association identified for human papillomavirus infections in lung cancer2014Inngår i: Cancer Research, ISSN 0008-5472, E-ISSN 1538-7445, Vol. 74, nr 13, s. 3525-3534Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Human papillomavirus (HPV) infections have been implicated in lung carcinogenesis, but causal associations remain uncertain. We evaluated a potential causal role for HPV infections in lung cancer through an analysis involving serology, tumor DNA, RNA, and p16 protein expression. Association between type-specific HPV antibodies and risk of lung cancer was examined among 3,083 cases and 4,328 controls in two case-control studies (retrospective) and one nested case-control study (prospective design). Three hundred and thirty-four available tumors were subjected to pathologic evaluation and subsequent HPV genotyping following stringent conditions to detect all high-risk and two low-risk HPV types. All HPV DNA-positive tumors were further tested for the expression of p16 protein and type-specific HPV mRNA. On the basis of the consistency of the results, although HPV11 and HPV31 E6 antibodies were associated with lung cancer risk in the retrospective study, no association was observed in the prospective design. Presence of type-specific antibodies correlated poorly with the presence of the corresponding HPV DNA in the tumor. Although nearly 10% of the lung tumors were positive for any HPV DNA (7% for HPV16 DNA), none expressed the viral oncogenes. No association was observed between HPV antibodies or DNA and lung cancer survival. In conclusion, we found no supportive evidence for the hypothesized causal association between HPV infections and lung cancer. (C) 2014 AACR.

  • 60. Ancelle-Park, R.
    et al.
    Armaroli, P.
    Ascunce, N.
    Bisanti, L.
    Bellisario, C.
    Broeders, M.
    Cogo, C.
    de Koning, H.
    Duffy, S. W.
    Frigerio, A.
    Giordano, L.
    Hofvind, S.
    Jonsson, Håkan
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Lynge, E.
    Massat, N.
    Miccinesi, G.
    Moss, S.
    Naldoni, C.
    Njor, S.
    Nyström, Lennarth
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin.
    Paap, E.
    Paci, E.
    Patnick, J.
    Ponti, A.
    Puliti, D.
    Segnan, N.
    Von Karsa, L.
    Tornberg, S.
    Zappa, M.
    Zorzi, M.
    Summary of the evidence of breast cancer service screening outcomes in Europe and first estimate of the benefit and harm balance sheet2012Inngår i: Journal of Medical Screening, ISSN 0969-1413, E-ISSN 1475-5793, Vol. 19, s. 5-13Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objectives To construct a European 'balance sheet' of key outcomes of population-based mammographic breast cancer screening, to inform policy-makers, stakeholders and invited women. Methods From the studies reviewed, the primary benefit of screening, breast cancer mortality reduction, was compared with the main harms, over-diagnosis and false-positive screening results (FPRs). Results Pooled estimates of breast cancer mortality reduction among invited women were 25% in incidence-based mortality studies and 31% in case-control studies (38% and 48% among women actually screened). Estimates of over-diagnosis ranged from 1% to 10% of the expected incidence in the absence of screening. The combined estimate of over-diagnosis for screened women, from European studies correctly adjusted for lead time and underlying trend, was 6.5%. For women undergoing 10 biennial screening tests, the estimated cumulative risk of a FPR followed by non-invasive assessment was 17%, and 3% having an invasive assessment. For every 1000 women screened biennially from age 50-51 until age 68-69 and followed up to age 79, an estimated seven to nine lives are saved, four cases are over-diagnosed, 170 women have at least one recall followed by non-invasive assessment with a negative result and 30 women have at least one recall followed by invasive procedures yielding a negative result. Conclusions The chance of saving a woman's life by population-based mammographic screening of appropriate quality is greater than that of over-diagnosis. Service screening in Europe achieves a mortality benefit at least as great as the randomized controlled trials. These outcomes should be communicated to women offered service screening in Europe.

  • 61. Andersen, Niels S
    et al.
    Pedersen, Lone B
    Laurell, Anna
    Elonen, Erkki
    Kolstad, Arne
    Boesen, Anne Marie
    Pedersen, Lars M
    Lauritzsen, Grete F
    Ekanger, Roald
    Nilsson-Ehle, Herman
    Nordström, Marie
    Fredén, Susanne
    Jerkeman, Mats
    Eriksson, Mikael
    Väärt, Jaan
    Malmer, Beatrice
    Umeå universitet, Medicinsk fakultet, Strålningsvetenskaper, Onkologi.
    Geisler, Christian H
    Pre-emptive treatment with rituximab of molecular relapse after autologous stem cell transplantation in mantle cell lymphoma.2009Inngår i: Journal of clinical oncology : official journal of the American Society of Clinical Oncology, ISSN 1527-7755, Vol. 27, nr 26, s. 4365-70Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    PURPOSE: Minimal residual disease (MRD) is predictive of clinical progression in mantle-cell lymphoma (MCL). According to the Nordic MCL-2 protocol we prospectively analyzed the efficacy of pre-emptive treatment using rituximab to MCL patients in molecular relapse after autologous stem cell transplantation (ASCT). PATIENTS AND MATERIALS: MCL patients enrolled onto the study, who had polymerase chain reaction (PCR) detectable molecular markers and underwent ASCT, were followed with serial PCR assessments of MRD in consecutive bone marrow and peripheral blood samples after ASCT. In case of molecular relapse with increasing MRD levels, patients were offered pre-emptive treatment with rituximab 375 mg/m(2) weekly for 4 weeks. RESULTS: Of 160 MCL patients enrolled, 145 underwent ASCT, of whom 78 had a molecular marker. Of these, 74 were in complete remission (CR) and four had progressive disease after ASCT. Of the CR patients, 36 underwent a molecular relapse up to 6 years (mean, 18.5 months) after ASCT. Ten patients did not receive pre-emptive treatment mainly due to a simultaneous molecular and clinical relapse, while 26 patients underwent pre-emptive treatment leading to reinduction of molecular remission in 92%. Median molecular and clinical relapse-free survival after pre-emptive treatment were 1.5 and 3.7 years, respectively. Of the 38 patients who remain in molecular remission for now for a median of 3.3 years (range, 0.4 to 6.6 years), 33 are still in clinical CR. CONCLUSION: Molecular relapse may occur many years after ASCT in MCL, and PCR based pre-emptive treatment using rituximab is feasible, reinduce molecular remission, and may prevent clinical relapse.

  • 62.
    Andersson, Anne
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Long-term side effects after treatment of Hodgkin's lymphoma2011Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Background Long-term side effects associated with the treatment of Hodgkin’s lymphoma (HL) have frequently been reported during the last decades. Studies have shown increased mortality in HL survivors. Following Hodgkin’s lymphoma, second malignancies (SM) and cardiovascular disease (CVD) are the most common causes of death in individuals treated for HL. This study investigates the incidence of side effects such as SM, CVD and infections in a cohort diagnosed with HL in Sweden between 1965 and 1995. In addition, this study identifies covariate risk factors for late side effects in order to develop strategies that prevent morbidity and mortality in HL survivors.

    Methods Using the Swedish Cancer Registry (SCR) at the National Board of Health and Welfare and the Multi-Generation Registry at Statistics (MGR) Sweden, we identified 6946 individuals diagnosed with HL between the years 1965 and 1995, and their first degree relatives (FDR) (n=17 858). In addition we identified the malignancies and inpatient care for CVD and infections for the HL cohort and their FDR. The standard incidence ratio (SIR) was calculated for the risk of SM, CVD and infections. For SM and CVD the risk also was stratified and calculated for family history of disease. The Swedish Hodgkin Intervention and Prevention study (SHIP), a prospective study, invited 702 individuals treated for HL at the age of 45 years or younger and who were treated in the region of Skåne, Uppsala or Umeå. The participants completed a questionnaire and were invited to an out-patient visit to an oncologist with clinical examination and blood tests. Any pathological findings were referred for further investigation.

    Results An increased risk for SM in HL long-term survivors was observed and seems to increase with the number of FDRs with cancer. There was also an increased risk for inpatient care due to congestive heart failure (CHF) and coronary artery disease (CAD). A family history of CHF and CAD further increased the risk for these diseases. The risk for inpatient care due to infections was increased and remained increased after 20 years or longer. The risk for infections was associated with splenectomy and hypothyroidism. Radiotherapy was an independent risk factor for cardiovascular disease in the cohort of the prospective study.

    ConclusionLong-term survivors from HL have an increased risk for developing late side effects such as SM, CVD and infections. Since many HL patients are young and the cure rate from the disease is high, it is of great importance to offer focused surveillance programs to selected individuals who are at high risk, e.g. individuals who received radiotherapy as part of their treatment and who have other known risk factors for cardiovascular disease such as hypertension, hypercholesterolemia, family history and smoking.

  • 63.
    Andersson, Anne
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Enblad, Gunilla
    Department of Oncology, Radiology and Clinical immunology, Section of Oncology, Uppsala University, Uppsala.
    Gustavsson, Anita
    Department of Oncology, Skåne University Hospital, Lund University, Lund .
    Erlanson, Martin
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Hagberg, Hans
    Department of Oncology, Radiology and Clinical immunology, Section of Oncology, Uppsala University, Uppsala .
    Molin, Daniel
    Department of Oncology, Radiology and Clinical immunology, Section of Oncology, Uppsala University, Uppsala .
    Tavelin, Björn
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Melin, Beatrice
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Long term risk of infections in Hodgkin lymphoma long-term survivors2011Inngår i: British Journal of Haematology, ISSN 0007-1048, E-ISSN 1365-2141, Vol. 154, nr 5, s. 661-663Artikkel i tidsskrift (Fagfellevurdert)
  • 64.
    Andersson, Anne
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Enblad, Gunilla
    Uppsala universitet.
    Gustavsson, Anita
    Lunds universitet.
    Erlanson, Martin
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Hagberg, Hans
    Uppsala universitet.
    Molin, Daniel
    Uppsala universitet.
    Tavelin, Björn
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Näslund, Ulf
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Melin, Beatrice
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Cardiovascular side effects following treatment of Hodgkin’s lymphoma: comorbidity factors and a strategy for interventionManuskript (preprint) (Annet vitenskapelig)
  • 65.
    Andersson, Anne
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Enblad, Gunilla
    Tavelin, Björn
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Björkholm, Magnus
    Linderoth, Johan
    Lagerlöf, I
    Merup, Mats
    Sender, Mark
    Malmer, Beatrice
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Family history of cancer as a risk factor for second malignancies after Hodgkin's lymphoma2008Inngår i: British Journal of Cancer, ISSN 0007-0920, E-ISSN 1532-1827, Vol. 98, nr 5, s. 1001-1005Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study estimated the risk of second primary malignancies after Hodgkin's lymphoma (HL) in relation to family history of cancer, age at diagnosis and latency, among 6946 patients treated for HL in Sweden in 1965–1995 identified through the Swedish Cancer Register (SCR). First-degree relatives (FDRs) to the HL patients and their malignancies were then ascertained together with their malignancies through the Multi-Generation Registry and SCR. The HL patient cohort was stratified on the number of FDRs with cancer, and standardised incidence ratios (SIRs) of developing SM were analysed. In the HL cohort, 781 SM were observed 1 year or longer after HL diagnosis. The risk for developing SM increased with the number of FDRs with cancer, SIRs being 2.26, 3.01, and 3.45 with 0, 1, or ≥2 FDRs with cancer, respectively. Hodgkin's lymphoma long-term survivors treated at a young age with a family history of cancer carry an increased risk for developing SM and may represent a subgroup where standardised screening for the most common cancer sites could be offered in a stringent surveillance programme.

  • 66.
    Andersson, Anne
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Näslund, Ulf
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Tavelin, Björn
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Enblad, Gunilla
    Gustavsson, Anita
    Malmer, Beatrice
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Long-term risk of cardiovascular disease in Hodgkin lymphoma survivors: retrospective cohort analyses and a concept for prospective intervention2009Inngår i: International Journal of Cancer, ISSN 0020-7136, E-ISSN 1097-0215, Vol. 124, nr 8, s. 1914-1917Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Previous studies have shown increased cardiovascular mortality as late side effects in Hodgkin lymphoma (HL) patients. This study identifies stratifying risk factors for surveillance and defines concepts for a clinical feasible and noninvasive prospective protocol for intervention of cardiovascular side effects. HL patients diagnosed between 1965 and 1995 (n = 6.946) and their first-degree relatives (FDR) were identified through the Swedish Cancer Registry and the Swedish Multigeneration Registry. For the HL and FDR cohort, in-patient care for cardiovascular disease (CVD) was registered through the Hospital Discharge Registry, Sweden. Standard incidence ratios of developing CVD for the HL cohort were calculated. A markedly increased risk for in-patient care of CVD was observed in HL patients with HL diagnosed at age 40 years or younger and with more than 10 years follow-up. In the HL survivors, a family history of congestive heart failure (CHF) and coronary artery disease (CAD) increased the risk for these diseases. The Swedish Hodgkin Intervention and Prevention study started in 2007. In the pilot feasibility study for prospective intervention (47 patients), about 25% of the cases had side effects and laboratory abnormalities. These patients were referred to a cardiologist or general practitioner. In the prospective cohort, a positive family history for CHF or CAD could be a stratifying risk factor when setting up a surveillance model. The prospective on-going study presents an intervention model that screens and treats for comorbidity factors. This article also presents an overview of the study concept.

  • 67.
    Andersson, Anne
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    von Wachenfeldt Väppling, Anna
    de Jong, Anna
    Nyström, Lennarth
    Umeå universitet, Medicinska fakulteten, Institutionen för epidemiologi och global hälsa.
    Adherence to adjuvant endocrine therapy after breast cancer in Sweden 2008-2010: a nationwide survey2019Inngår i: Journal of Clinical Oncology, ISSN 0732-183X, E-ISSN 1527-7755, Vol. 37, nr 15, s. 523-523Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    Background: In estrogen receptor (ER) positive early breast cancer (EBC) adjuvant endocrine therapy (AET) is crucial to reduce recurrence and mortality. Previous studies have shown that adherence to AET is lower than expected and could negatively affect outcome. Since the year of 2000, BC patients in Sweden are treated in accordance to national guidelines. Treatment is offered at a low cost for the patient. The aim of the study was to estimate the adherence to AET in Sweden by regions and age groups. Methods: Women with a first primary EBC diagnosis 2008-2010 were identified through the Swedish Cancer Registry (SCR). Individual tumour and treatment data were retrieved from the Swedish National Breast Cancer Registry (SNBCR). Patients with ER negative tumours, small tumours (≤ 10 mm) and metastatic disease was excluded from the study since there were no indication to AET. Likewise, were individuals with AET registered to be administered by a third part excluded. Dispensed treatment from pharmacies was obtained through the Swedish Prescription Registry and medication possession rate (MPR) was calculated as number of dispensed doses divided by treatment duration in days. Good adherence to treatment in a patient was set at MPR ≥ 80 %. Adherence was calculated for 3 and 5 years. Results: Twenty-one thousand sixteen (21 016) individuals with a first primary BC between 2008 and 2010 was identified through SCR of which 20 596 were registered in the SNBCR. A total of 10 176 met the inclusion criteria in the study. Adherence after 3 years was 88.0 % and after 5 years 82.5 %. Adherence differed between regions in Sweden and was positively associated with age at diagnosis between 41-74 years. Urban areas had a lower adherence than rural areas (80.7 % vs 83.6 %; p= <0.001). Conclusions: Adherence to AET in Sweden was good, although there were differences by age and urban and rural areas. Further studies are needed to identify factors affecting differences in adherence, with the purpose of initiate actions to increase adherence to AET in ER positive EBC patients.

  • 68.
    Andersson, Britta
    et al.
    Umeå universitet, Medicinsk fakultet, Medicinsk biovetenskap, Klinisk kemi. Klinisk kemi.
    Behnam Motlagh, Parviz
    Umeå universitet, Medicinsk fakultet, Strålningsvetenskaper, Onkologi. Onkologi.
    Henriksson, Roger
    Umeå universitet, Medicinsk fakultet, Strålningsvetenskaper, Onkologi. Onkologi.
    Grankvist, Kjell
    Umeå universitet, Medicinsk fakultet, Medicinsk biovetenskap, Klinisk kemi. Klinisk kemi.
    Pharmacological modulation of lung cancer cells for potassium ion depletion2005Inngår i: Anticancer Research, ISSN 0250-7005, E-ISSN 1791-7530, Vol. 25, nr 4, s. 2609-2616Artikkel i tidsskrift (Fagfellevurdert)
  • 69.
    Andersson, Britta
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Klinisk kemi. Klinisk kemi.
    Janson, Veronica
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Klinisk kemi. Klinisk kemi.
    Behnam Motlagh, Parviz
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Klinisk kemi.
    Henriksson, Roger
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi. Onkologi.
    Grankvist, Kjell
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Klinisk kemi. Klinisk kemi.
    Induction of apoptosis by intracellular potassium ion depletion: using the fluorescent dye PBFI in a 96-well plate method in cultured lung cancer cells.2006Inngår i: Toxicology in Vitro, ISSN 0887-2333, E-ISSN 1879-3177, Vol. 20, nr 6, s. 986-994Artikkel i tidsskrift (Fagfellevurdert)
  • 70.
    Andersson, Charlotta
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Klinisk kemi.
    Li, Xingru
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Klinisk kemi.
    Lorenz, Fryderyk
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Golovleva, Irina
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Medicinsk och klinisk genetik.
    Wahlin, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Li, Aihong
    Umeå universitet, Medicinska fakulteten, Institutionen för medicinsk biovetenskap, Klinisk kemi.
    Reduction in WT1 Gene Expression During Early Treatment Predicts the Outcome in Patients With Acute Myeloid Leukemia2012Inngår i: Diagnostic molecular pathology (Print), ISSN 1052-9551, E-ISSN 1533-4066, Vol. 21, nr 4, s. 225-233Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Wilms tumor gene 1 (WT1) expression has been suggested as an applicable minimal residual disease marker in acute myeloid leukemia (AML). We evaluated the use of this marker in 43 adult AML patients. Quantitative assessment of WT1 gene transcripts was performed using real-time quantitative-polymerase chain reaction assay. Samples from both the peripheral blood and the bone marrow were analyzed at diagnosis and during follow-up. A strong correlation was observed between WT1 normalized with 2 different control genes (beta-actin and ABL1, P < 0.001). WT1 mRNA level at diagnosis was of no prognostic relevance (P > 0.05). A >= 1-log reduction in WT1 expression in bone marrow samples taken < 1 month after diagnosis significantly correlated with an improved overall survival (P = 0.004) and freedom from relapse (P = 0.010) when beta-actin was used as control gene. Furthermore, a reduction in WT1 expression by >= 2 logs in peripheral blood samples taken at a later time point significantly correlated with a better outcome for overall survival (P = 0.004) and freedom from relapse (P = 0.012). This result was achieved when normalizing against both b-actin and ABL1. These results therefore suggest that WT1 gene expression can provide useful information for minimal residual disease detection in adult AML patients and that combined use of control genes can give more informative results.

  • 71.
    Andersson, Hanna
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Do rehabilitation needs change during first year after completed adjuvant chemotherapy?2018Independent thesis Basic level (professional degree), 20 poäng / 30 hpOppgave
  • 72.
    Andersson, Jenny
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Allmänmedicin.
    Salander, Pär
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för socialt arbete. Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Onkologi.
    Brandstetter-Hiltunen, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Knutsson, Emma
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Hamberg, Katarina
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Allmänmedicin. Umeå universitet, Samhällsvetenskapliga fakulteten, Umeå centrum för genusstudier (UCGS).
    Is it possible to identify patient´s sex when reading blinded illness narratives? An experimental study about gender bias2008Inngår i: International Journal for Equity in Health, ISSN 1475-9276, E-ISSN 1475-9276, Vol. 7, nr 21, s. 1-9Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: In many diseases men and women, for no apparent medical reason, are not offered the same investigations and treatment in health care. This may be due to staff's stereotypical preconceptions about men and women, i.e., gender bias. In the clinical situation it is difficult to know whether gender differences in management reflect physicians' gender bias or male and female patients' different needs or different ways of expressing their needs. To shed some light on these possibilities this study investigated to what extent it was possible to identify patients' sex when reading their blinded illness narratives, i.e., do male and female patients express themselves differently enough to be recognised as men and women without being categorised on beforehand?

    Methods: Eighty-one authentic letters about being diseased by cancer were blinded regarding sex and read by 130 students of medicine and psychology. For each letter the participants were asked to give the author's sex and to explain their choice. The success rates were analysed statistically. To illuminate the participants' reasoning the explanations of four letters were analysed qualitatively.

    Results: The patient's sex was correctly identified in 62% of the cases, with significantly higher rates in male narratives. There were no differences between male and female participants. In the qualitative analysis the choice of a male writer was explained by: a short letter; formal language; a focus on facts and a lack of emotions. In contrast the reasons for the choice of a woman were: a long letter; vivid language; mention of emotions and interpersonal relationships. Furthermore, the same expressions were interpreted differently depending on whether the participant believed the writer to be male or female.

    Conclusion: It was possible to detect gender differences in the blinded illness narratives. The students' explanations for their choice of sex agreed with common gender stereotypes implying that such stereotypes correspond, at least on a group level, to differences in male and female patients' illness descriptions. However, it was also obvious that preconceptions about gender obstructed and biased the interpretations, a finding with implications for the understanding of gender bias in clinical practice.

  • 73.
    Andersson, Jonas
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik. Norrlands universitetssjukhus.
    Fysik och teknik: konventionell planar röntgen2013Inngår i: Nuklearmedicin / [ed] Sven-Ola Hietala, Katrine Åhlström Riklund, Lund: Studentlitteratur AB, 2013, 2, s. 40-46Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 74.
    Andersson, Jonas
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Ion recombination in liquid ionization chambers: development of an experimental method to quantify general recombination2013Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    An experimental method (the two-dose-rate method) for the correction of general recombination losses in liquid ionization chambers has been developed and employed in experiments with different liquids and radiation qualities. The method is based on a disassociation of initial and general recombination, since an ionized liquid is simultaneously affected by both of these processes.

    The two-dose-rate method has been compared to an existing method for general recombination correction for liquid ionization chambers, and has been found to be the most robust method presently available.

    The soundness of modelling general recombination in liquids on existing theory for gases has been evaluated, and experiments indicate that the process of general recombination is similar in a gas and a liquid. It is thus reasonable to employ theory for gases in the two-dose-rate method to achieve experimental corrections for general recombination in liquids. There are uncertainties in the disassociation of initial and general recombination in the two-dose-rate method for low applied voltages, where initial recombination has been found to cause deviating results for different liquids and radiation qualities.

    Sensitivity to ambient electric fields has been identified in the microLion liquid ionization chamber (PTW, Germany). Experimental data may thus be perturbed if measurements are conducted in the presence of ambient electric fields, and the sensitivity has been found to increase with an increase in the applied voltage. This can prove to be experimentally limiting since general recombination may be too severe for accurate corrections if the applied voltage is low.

  • 75.
    Andersson, Jonas
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Radiation Dosimetry for CBCT – Quality Control and Applied Dosimetry2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The use of Cone Beam CT (CBCT) devices in health care has increased in recent years. Unfortunately, this trend has not been followed by a standardization of dose metrics for Quality Control (QC), or a necessary evolution of applied dosimetry for assessment of patient dose.

    The European Federation of Organisations in Medical Physics (EFOMP) has drafted a report on the property of QC for CBCT devices. The report contains objective, practical and unifying methodology for QC of CBCT used in oral radiology, radiotherapy, interventional radiology and guided surgery. The dose metrics discussed include the Computed Tomography Dose Index (CTDI), Kerma-Area Product (KAP) and detector incident air kerma. The report concludes that KAP-meters are preferable for QC as long as they can be mounted on the X-ray tube housing. Otherwise measurements of detector incident kerma seem to offer a practical solution for QC.

    The European Radiation Dosimetry Group (EURADOS) are preparing a literature review on patient dose from various applications of CBCT, which will in part be included in the EFOMP report. Most studies on patient dose from CBCT examinations and interventional procedures are based on thermoluminescent dosimeter (TLD) measurements in Rando phantoms. While helpful to the community, these studies yield substantial uncertainty when applied in the clinical reality of medical physicists working with justification and optimization. Applied dosimetry for CBCT needs to evolve and adopt recent theoretical advances to allow robust estimates of patient dose.

  • 76.
    Andersson, Jonas
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    TG246 On Patient Dose From Diagnostic Radiation: Acceptance Testing and Dose Measurements with CT2014Inngår i: 56th AAPM Annual Meeting and Exhibition 2014, Austin, TX, USA, July 20-24 (2014), 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Radiation dose from diagnostic and interventional use of ionizing radiation continues to be a focus of the regulatory, accreditation and standards organizations in the US and Europe. A Joint AAPM/EFOMP effort has been underway in the past year – having the goal to assist the clinical medical physicist with communicating optional and varied approaches in estimating (and validating) patient dose. In particular, the tools provided by DICOM Radiation Dose Structured Reports, either by themselves or as part of a networked data repository of dose related information are a rich source of actionable information. The tools of the medical physicist have evolved to include using DICOM data in meaningful ways to look at patient dose with respect to imaging practices. In addition to how accurate or reproducible a dose value is (totally necessary and our traditional workspace) it is now being asked how reproducible (patient to patient, device to device) are the delivered doses? Clinical medical physicists are best equipped to assist our radiology and technologist colleagues with this effort. The purpose of this session is to review the efforts of TG246 - bringing forward a summary content of the TG246 Report including specific dose descriptors for CT and Fluoroscopy – particularly in a focus of leveraging the RDSR as a means for monitoring good practices according to the ALARA principle. Additionally, rapidly evolving technologies for more refined dose estimates are now in use. These will be presented as they look to having highly patient specific dose estimates in automated use.

  • 77.
    Andersson, Jonas
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Granberg, Christoffer
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Riklund, Katrine
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi.
    A novel system for quality assurance of radiology equipment2018Inngår i: Eurosafe Imaging 2018, 2018Konferansepaper (Fagfellevurdert)
  • 78.
    Andersson, Jonas
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Johansson, Erik
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Tölli, Heikki
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    On the property of measurements with the PTW microLion chamber in continuous beam2012Inngår i: Medical physics (Lancaster), ISSN 0094-2405, Vol. 39, nr 8, s. 4775-4787Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose: The performance of liquid ionization chambers, which may prove to be useful tools in the field of radiation dosimetry, is based on several chamber and liquid specific characteristics. The present work investigates the performance of the PTW microLion liquid ionization chamber with respect to recombination losses and perturbations from ambient electric fields at various dose rates in continuous beams.

    Methods: In the investigation, experiments were performed using two microLion chambers, containing isooctane (C8H18) and tetramethylsilane (Si(CH3)4) as the sensitive media, and a NACP-02 monitor chamber. An initial activity of approximately 250 GBq 18F was employed as the radiation source in the experiments. The initial dose rate in each measurement series was estimated to 1.0 Gy min-1 by Monte Carlo simulations and the measurements were carried out during the decay of the radioactive source. In the investigation of general recombination losses, employing the two-dose-rate method for continuous beams, the liquid ionization chambers were operated at polarizing voltages 25, 50, 100, 150, 200 and 300 V. Furthermore, measurements were also performed at 500 V polarizing voltage in the investigation of the sensitivity of the microLion chamber to ambient electric fields.

    Results: The measurement results from the liquid ionization chambers, corrected for general recombination losses according to the two-dose-rate method for continuous beams, had a good agreement with the signal to dose linearity from the NACP-02 monitor chamber for general collection efficiencies above 70%. The results also displayed an agreement with the theoretical collection efficiencies according to the Greening theory, except for the liquid ionization chamber containing isooctane operated at 25 V. At lower dose rates, perturbations from ambient electric fields were found in the microLion chamber measurement results. Due to the perturbations, measurement results below an estimated dose rate of 0.2 Gy min-1 were excluded from the present investigation of the general collection efficiency. The perturbations were found to be more pronounced when the chamber polarizing voltage was increased.

    Conclusions: By using the two-dose-rate method for continuous beams, comparable corrected ionization currents from experiments in low- and medium energy photon beams can be achieved. However, the valid range of general collection efficiencies has been found to vary in a comparison between experiments performed in continuous beams of 120 kVp x-ray, and the present investigation of 511 keV annihilation photons. At very high dose rates in continuous beams, there are presently no methods that can be used to correct for general recombination losses and at low dose rates the microLion chamber may be perturbed by ambient electric fields. Increasing the chamber polarizing voltage, which diminishes the general recombination effect, was found to increase the microLion chamber sensitivity to ambient electric fields. Prudence is thus advised when employing the microLion chamber in radiation dosimetry, as ambient electric fields of the strength observed in the present work may be found in many common situations. Due to uncertainties in the theoretical basis for recombination losses in liquids, further studies on the underlying theories for the initial and general recombination effect are needed if liquid ionization chambers are to become a viable option in high precision radiation dosimetry.

  • 79.
    Andersson, Jonas
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Kaiser, Franz-Joachim
    Gómez, Faustino
    Jäkel, Oliver
    Pardo-Montero, Juan
    Tölli, Heikki
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    A comparison of different experimental methods for general recombination correction for liquid ionization chambers2012Inngår i: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 57, nr 21, s. 7161-7175Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Radiation dosimetry of highly modulated dose distributions requires a detector with a high spatial resolution. Liquid filled ionization chambers (LICs) have the potential to become a valuable tool for the characterization of such radiation fields. However, the effect of an increased recombination of the charge carriers, as compared to using air as the sensitive medium has to be corrected for. Due to the presence of initial recombination in LICs, the correction for general recombination losses is more complicated than for air-filled ionization chambers. In the present work, recently published experimental methods for general recombination correction for LICs are compared and investigated for both pulsed and continuous beams. The experimental methods are all based on one of two approaches, either measurements at two different dose rates (two-dose-rate methods), or measurements at three different LIC polarizing voltages (three-voltage methods). In a comparison with the two-dose-rate methods, the three-voltage methods fail to achieve accurate corrections in several instances, predominantly at low polarizing voltages and dose rates. However, for continuous beams in the range of polarizing voltages recommended by the manufacturer of the LICs used, the agreement between the different methods is generally within the experimental uncertainties. For pulsed beams, the agreement between the methods is poor. The inaccuracies found in the results from the three-voltage methods are associated with numerical difficulties in solving the resulting equation systems, which also make these methods sensitive to small variations in the experimental data. These issues are more pronounced for the case of pulsed beams. Furthermore, the results suggest that the theoretical modelling of initial recombination used in the three-voltage methods may be a contributing factor to the deviating results observed.

  • 80.
    Andersson, Jonas
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Karpe, Fredrik
    NIHR Oxford Biomedical Research Centre, Churchill Hospital, Oxford, UK.
    Sjöström, Lars-Göran
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Riklund, Katrine
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi.
    Söderberg, Stefan
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Kardiologi.
    Olsson, Tommy
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Association of adipose tissue blood flow with fat depot sizes and adipokines in women2012Inngår i: International Journal of Obesity, ISSN 0307-0565, E-ISSN 1476-5497, Vol. 36, nr 6, s. 783-789Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objective: To explore possible associations between adipose tissue (AT) blood flow (ATBF), AT depot sizes and adipocyte-derived hormones (adipokines) in women.

    Subjects: In all, 43 healthy women were divided into four groups: normal-weight (n=11) and obese (n=11) pre-menopausal women and normal-weight (n=10) and obese (n=11) post-menopausal women.

    Methods: Fasting levels of adipokines were obtained, and a single-slice computed tomography scan at the level of L4-L5 was used to estimate fat depot sizes. ATBF was assessed by xenon washout while in a fasting state and after oral glucose load. We also measured glucose, insulin and non-esterified fatty acids.

    Results: Total, subcutaneous and visceral AT areas strongly correlated with ATBF (all P<0.001). Circulating leptin levels strongly and inversely correlated with ATBF (P=0.001), but this association did not remain after adjustment for body mass index. Adiponectin was not associated with blood flow.

    Conclusion: ATBF is closely linked to subcutaneous and visceral AT size. Further analyses are needed to determine possible mediators of this association, including mechanistic studies to assess a putative role for leptin as a significant modulator of blood flow. International Journal of Obesity advance online publication, 26 July 2011; doi:10.1038/ijo.2011.152.

  • 81.
    Andersson, Jonas
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Mellberg, Caroline
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Otten, Julia
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Ryberg, Mats
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Rinnström, Daniel
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Kardiologi.
    Larsson, Christel
    Lindahl, Bernt
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Yrkes- och miljömedicin.
    Hauksson, Jon
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. d Department of Radiography and Biomedical Science, Faculty of Medicine, University of Iceland, Reykjavik, Iceland.
    Johansson, Bengt
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Kardiologi.
    Olsson, Tommy
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Left ventricular remodelling changes without concomitant loss of myocardial fat after long-term dietary intervention2016Inngår i: International Journal of Cardiology, ISSN 0167-5273, E-ISSN 1874-1754, Vol. 216, s. 92-96Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: Accumulation of myocardial triglycerides (MTG) is associated with impaired left ventricular (LV) remodelling and function in obese and diabetic subjects. The role of MTG accumulation in development of heart failure in this group of patients is unknown. Short-term studies suggest that diets that lead to weight loss could mobilize MTG, with a favourable effect on cardiac remodelling. In a 24-month, randomized, investigator-blinded study, we assessed the effect of two different diets and subsequent weight loss on cardiac function and MTG in postmenopausal women. Methods: Sixty-eight healthy postmenopausal women with body mass index [BMI] >= 27 kg/m(2) were randomized to an ad libitum Palaeolithic diet (PD) or a Nordic Nutrition Recommendation (NNR) diet for 24 months. Morphology, cardiac function, and MTG levels were measured using magnetic resonance (MR) scanning, including proton spectroscopy at baseline and 6 and 24 months. Results: Despite mean weight losses of 4.9 (1.0) kg (NNR) and 7.8 (1.1) kg (PD), the MTG content did not change over time (p = 0.98 in the NNR and p = 0.11 in the PD group at 24 months). Reduced left ventricular mass was observed in both diet groups over 24 months. Blood pressure was reduced at 6 months, but returned to baseline levels at 24 months. End diastolic volume, stroke volume, and cardiac output decreased over time. No differences between diet groups were observed. Conclusions: Diet intervention and moderate weight loss over 24 months improved LV remodelling but did not alter MTG levels in overweight/obese postmenopausal women.

  • 82.
    Andersson, Jonas
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Pavlicek, William
    Patient organ dose with computed tomography - a review of present methodology and DICOM information: executive summary of the joint report of AAPM task group 246 and EFOMP2016Inngår i: ECR 2016 Book of Abstracts, 2016, Vol. 7, nr 1, artikkel-id B0303Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Purpose: The justification and optimisation of medical imaging employing ionizing radiation have been intensely discussed in recent years, particularly for computed tomography (CT). A key point in this discussion is the estimation of patient dose, which commonly employs radiation output metrics developed for quality assurance and no patient specific information. Such patient dose estimates are of limited value, and more refined methods needs to be promoted and provided to the community.

    Methods and Materials: AAPM Task Group 246 was formed in 2013, and in a joint venture with EFOMP charged with summarizing present methodology and DICOM information available for estimating patient dose with computed tomography.

    Results: The Joint Report of AAPM Task Group 246 and EFOMP is a comprehensive resource for the clinical medical physicist. The possibilities of patient specific dosimetry from the Computed Tomography Dose Index (CTDIvol), to the Size-Specific Dose Estimates (SSDE) and advanced Monte Carlo methods are discussed together with available DICOM information, as well as practical examples on how patient dose estimates can be achieved. The report also summarizes important factors contributing to the uncertainty in patient dose estimates and gives examples of achievable confidence intervals.

    Conclusion: The SSDE and Monte Carlo methods can together with detailed scanner, examination and patient specific DICOM information offer refined estimates of patient dose for justification and optimisation of CT examinations. Given the present robustness of available methods AAPM Task Group 246 and EFOMP recommend that all reports of patient dose should be accompanied by estimates of the associated uncertainty.

  • 83.
    Andersson, Jonas
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Sjöström, Lars-Göran
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Karlsson, Marcus
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Wiklund, Urban
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Hultin, Magnus
    Umeå universitet, Medicinska fakulteten, Institutionen för kirurgisk och perioperativ vetenskap, Anestesiologi och intensivvård.
    Karpe, Fredrik
    Olsson, Tommy
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Dysregulation of subcutaneous adipose tissue blood flow in overweight postmenopausal women2010Inngår i: Menopause: The Journal of the North American Menopause, ISSN 1072-3714, E-ISSN 1530-0374, Vol. 17, nr 2, s. 365-371Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVE: A putative link between abdominal obesity and metabolic-vascular complications after menopause may be due to a decreased adipose tissue blood flow (ATBF). The present work aimed to analyze possible changes in ATBF with being overweight and menopausal and its putative link to endothelial dysfunction and autonomic nervous system balance.

    METHODS: Forty-three healthy women were classified into four groups according to weight and menopause status. The ATBF was measured by xenon washout while fasting and after oral glucose intake. The nitric oxide synthase inhibitor asymmetric dimethylarginine was used as a marker of endothelial function and heart rate variability-estimated autonomic nervous system activity.

    RESULTS: Fasting ATBF was decreased in both overweight groups (P = 0.044 and P = 0.048) versus normal-weight premenopausal women. Normal-weight and overweight postmenopausal women exhibited lower maximum ATBF compared with normal-weight premenopausal women (P = 0.015 and P = 0.001, respectively), and overweight postmenopausal women exhibited lower maximum ATBF compared with normal-weight postmenopausal women (P = 0.003). A negative correlation was found between fasting ATBF and asymmetric dimethylarginine (P = 0.015), whereas maximum ATBF was negatively associated with sympathetic-parasympathetic nervous system balance (ratio of the power of the low frequency to the power of the high frequency; P = 0.002).

    CONCLUSIONS: Loss of ATBF flexibility in overweight postmenopausal women may contribute to the metabolic dysfunction seen in this group of women.

  • 84.
    Andersson, Jonas
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Tölli, Heikki
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Application of the two-dose-rate method for general recombination correction for liquid ionization chambers in continuous beams2011Inngår i: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 56, nr 2, s. 299-314Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A method to correct for the general recombination losses for liquid ionization chambers in continuous beams has been developed. The proposed method has been derived from Greening's theory for continuous beams and is based on measuring the signal from a liquid ionization chamber and an air filled monitor ionization chamber at two different dose rates. The method has been tested with two plane parallel liquid ionization chambers in a continuous radiation x-ray beam with a tube voltage of 120 kV and with dose rates between 2 and 13 Gy min-1. The liquids used as sensitive media in the chambers were isooctane (C8H18) and tetramethylsilane (Si(CH3)4). The general recombination effect was studied using chamber polarizing voltages of 100, 300, 500, 700 and 900 V for both liquids. The relative standard deviation of the results for the collection efficiency with respect to general recombination was found to be a maximum of 0.7 % for isooctance and 2.4 % for tetramethylsilane. The results are in excellent agreement with Greening's theory for collection efficiencies over 90 %. The measured and corrected signals from the liquid ionization chambers used in this work are in very good agreement with the air filled monitor chambers with respect to signal to dose linearity.

  • 85.
    Andersson, Jonas
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Tölli, Heikki
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Modeling ion recombination in liquid ionization chambers: Improvement and analysis of the two-dose-rate method2017Inngår i: Medical physics (Lancaster), ISSN 0094-2405, Vol. 44, nr 11, s. 5977-5987Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose: The use of liquid ionization chambers can provide useful information to endeavors with radiation dosimetry for highly modulated beams. Liquid ionization chambers may be particularly suitable for computed tomography applications where conventional ionization chambers do not present a high enough sensitivity for the spatial resolution required to characterize common X-ray beams. Due to the sensitivity, which leads to high charge densities, liquid ionization chambers can suffer from large recombination losses leading to degradation in signal to dose rate linearity. To solve this problem, a two-dose-rate method for general recombination correction has been proposed for liquid ionization chambers. However, the valid range of recombination losses that the method can accurately account for has been found to vary depending on radiation quality. The present work provides an in-depth analysis of the performance of the two-dose-rate method. Furthermore, the soundness of applying gas theory to liquids is investigated by using the two-dose-rate method.

    Methods: In the present work, the two-dose-rate method for general recombination correction of liquid ionization chambers used in continuous beams is studied by employing theory for gas-filled ionization chambers. An approximate relation for the general collection efficiency containing a material-specific parameter that is traceable to liquids has been derived for theoretical and experimental investigation alongside existing theory. Furthermore, the disassociation between initial and general recombination in the method is analyzed both theoretically and experimentally.

    Results: The results indicate that liquids and gases share general recombination characteristics, where the liquids investigated (isooctane and tetramethylsilane) to a large extent mimic the behavior theoretically expected in gases. Furthermore, it is shown that the disassociation between initial and general recombination in the two-dose-rate method is an approximation that depends on the relation between initial recombination and the collecting electric field strength at the dose rates used.

    Conclusions: Due to the approximation used to separate initial and general recombination the valid range of collection efficiencies for the two-dose-rate method will not only depend on the model used to describe general recombination but also on the type of liquid and radiation beam quality. As there is no robust theory for initial recombination in liquids to apply, the valid range of general collection efficiencies for the two-dose-rate method should be experimentally evaluated for each radiation dosimetry application.

  • 86.
    Andersson, Jonas
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Tölli, Heikki
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    The Use of Liquid Ionization Chambers in Radiation Dosimetry2012Inngår i: World Congress on Medical Physics and Biomedical Engineering May 26-31, 2012 Beijing, China / [ed] Mian Long, Springer, 2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Liquid ionization chambers (LICs) have found applications in many fields in radiation dosimetry, e.g. IMRT, hadron therapy, brachytherapy and computed tomography. The wide range of applications is made possible due to the high sensitivity of LICs, allowing them to be manufactured with small physical dimensions of the chamber body and the effective measurement volume. Furthermore, the commonly used liquids (such as isooctane) have radiation absorption characteristics similar to water, introducing only small fluence perturbation effects as compared to conventional dosimeters. The small dimension of the effective measurement volume is beneficial for the quantification of radiation beams with steep gradients, while retaining a high measurement signal with good statistical properties. However, the interpretation of measurement results is not straight-forward due to several factors influencing their performance. Here, the main problems are recombination effects and particle type- and energy dependence, which may cause severe non-linear effects. The loss of measurement signal in LICs is due to both initial and general recombination. In the present work it is shown that the general recombination effect can be treated with in a similar manner as for air-filled ionization chambers, while there are currently no theories that adequately describe the initial recombination effect for LICs. Furthermore, the relationship between energy dependence and recombination losses in LICs are evaluated at different radiation qualities. Recently developed methods for the correction of general recombination losses in LICs are discussed and their validity evaluated.

  • 87.
    Andersson, Kennet
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Assessment of cerebrospinal fluid system dynamics: novel infusion protocol, mathematical modelling and parameter estimation for hydrocephalus investigations2011Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Patients with idiopathic normal pressure hydrocephalus (INPH) have a disturbance in the cerebrospinal fluid (CSF) system. The treatment is neurosurgical – a shunt is placed in the CSF system. The infusion test is used to assess CSF system dynamics and to aid in the selection of patients that will benefit from shunt surgery. The infusion test can be divided into three parts: a mathematical model, an infusion protocol and a parameter estimation method. A non-linear differential equation is used to mathematically describe the CSF system, where two important parameters are the outflow conductance (Cout) and the Pressure Volume Index (PVI). These are used both for clinical and research purposes. The analysis methods for the non-linear CSF system have limited the infusion protocols of presently used infusion investigations. They come with disadvantages such as long investigation time, no estimation of PVI and no measure of the reliability of the estimates.

    The aim of this dissertation was to develop and evaluate novel methods for infusion protocols, mathematical modelling and parameter estimation methods for assessment of CSF system dynamics.

    The infusion protocols and parameter estimation methods in current use, constant pressure infusion (CPI), constant infusion and bolus infusion, were investigated. The estimates of Cout were compared, both on an experimental set-up and on 20 INPH patients. The results showed that the bolus method produced a significantly higher Cout than the other methods. The study suggested a method with continuous infusion for estimating Cout and emphasized that standardization of Cout measurement is necessary.

    The non-linear model of the CSF system was further developed. The ability to model physiological variations that affect the CSF system was incorporated into the model and it was transformed into a linear time-invariant system. This enabled the use of methods developed for identification of such systems. The underlying model for CSF absorption was discussed and the effect of baseline resting pressure (Pr) in the analysis on the estimation of Cout was explored using two different analyses, with and without Pr.

    A novel infusion protocol with an oscillating pressure pattern was introduced. This protocol was theoretically better suited for the CSF system characteristics. Three new parameter estimation methods were developed. The adaptive observer was developed from the original non-linear model of the CSF system and estimated Cout in real time. The prediction error method (PEM) and the robust simulation error (RSE) method were based on the transformed linear system, and they estimated both Cout and PVI with confidence intervals in real time. Both the oscillating pressure pattern and the reference CPI protocol were performed on an experimental set-up of the CSF system and on 47 hydrocephalus patients. The parameter estimation methods were applied to the data, and the RSE method produced estimates of Cout that were in good agreement with the reference method and allowed for an individualized and considerably reduced investigation time.

    In summary, current methods have been investigated and a novel approach for assessment of CSF system dynamics has been presented. The Oscillating Pressure Infusion method, which includes a new infusion protocol, a further developed mathematical model and new parameter estimation methods has resulted in an improved way to perform infusion investigations and should be used when assessing CSF system dynamics. The advantages of the new approach are the pressure-regulated infusion protocol, simultaneous estimation of Cout and PVI and estimates of reliability that allow for an individualized investigation time.

  • 88.
    Andersson, Kennet
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Novel infusion method for measurement of CSF dynamicsManuskript (preprint) (Annet vitenskapelig)
  • 89.
    Andersson, Kennet
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Manchester, I. R.
    Laurell, Katarina
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Cesarini, K. Giuliana
    Malm, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Eklund, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik. Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Centrum för medicinsk teknik och fysik (CMTF).
    Measurement of CSF dynamics with oscillating pressure infusion2013Inngår i: Acta Neurologica Scandinavica, ISSN 0001-6314, E-ISSN 1600-0404, Vol. 128, nr 1, s. 17-23Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Introduction Infusion tests are used to diagnose and select patients with idiopathic normal pressure hydrocephalus (INPH) for shunt surgery. The test characterizes cerebrospinal fluid dynamics and estimates parameters of the cerebrospinal fluid system, the pressure-volume index (PVI) and the outflow conductance (Cout). The Oscillating Pressure Infusion (OPI) method was developed to improve the test and reduce the investigation time. The aim of this study was to evaluate the new OPI method by comparing it with an established reference method. Methods Forty-seven patients (age 71.2 +/- 8.9years) with communicating hydrocephalus underwent a preoperative lumbar infusion investigation with two consecutive infusion protocols, reference (42min) and new (20min), that is, 94 infusion tests in total. The OPI method estimated Cout and PVI simultaneously. A real-time analysis of reliability was applied to investigate the possibility of infusion time reduction. Results The difference in Cout between the methods was 1.2 +/- 1.8l/s/kPa (Rout=-0.8 +/- 3.5mmHg/ml/min), P<0.05, n=47. With the reliability analysis, the preset 20min of active infusion could have been even further reduced for 19 patients to between 10 and 19min. PVI was estimated to 16.1 +/- 6.9ml, n=47. Conclusions The novel Oscillating Pressure Infusion method produced real-time estimates of Cout including estimates of reliability that was in good agreement with the reference method and allows for a reduced and individualized investigation time.

  • 90.
    Andersson, Kennet
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Manchester, Ian R
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Andersson, Nina
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Shiriaev, Anton
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Malm, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurologi.
    Eklund, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Assessment of cerebrospinal fluid outflow conductance using an adaptive observer-experimental and clinical evaluation2007Inngår i: Physiological Measurement, ISSN 0967-3334, E-ISSN 1361-6579, Vol. 28, nr 11, s. 1355-1368Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Idiopathic normal pressure hydrocephalus (INPH) patients have a disturbance in the dynamics of the cerebrospinal fluid (CSF) system. The outflow conductance, C, of the CSF system has been suggested to be prognostic for positive outcome after treatment with a CSF shunt. All current methods for estimation of C have drawbacks; these include lack of information on the accuracy and relatively long investigation times. Thus, there is a need for improved methods. To accomplish this, the theoretical framework for a new adaptive observer (OBS) was developed which provides real-time estimation of C. The aim of this study was to evaluate the OBS method and to compare it with the constant pressure infusion (CPI) method. The OBS method was applied to data from infusion investigations performed with the CPI method. These consisted of repeated measurements on an experimental set-up and 30 patients with suspected INPH. There was no significant difference in C between the CPI and the OBS method for the experimental set-up. For the patients there was a significant difference, −0.84 ± 1.25 µl (s kPa)−1, mean ± SD (paired sample t-test, p < 0.05). However, such a difference is within clinically acceptable limits. This encourages further development of this new real-time approach for estimation of the outflow conductance.

  • 91.
    Andersson, Kennet
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Manchester, Ian R
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Malm, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Neurologi.
    Eklund, Anders
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Centrum för medicinsk teknik och fysik (CMTF). Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Real-time estimation of cerebrospinal fluid system parameters via oscillating pressure infusion2010Inngår i: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 48, nr 11, s. 1123-1131Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hydrocephalus is related to a disturbed cerebrospinal fluid (CSF) system. For diagnosis, lumbar infusion test are performed to estimate outflow conductance, C (out), and pressure volume index, PVI, of the CSF system. Infusion patterns and analysis methods used in current clinical practice are not optimized. Minimizing the investigation time with sufficient accuracy is of major clinical relevance. The aim of this study was to propose and experimentally evaluate a new method, the oscillating pressure infusion (OPI). The non-linear model of the CSF system was transformed into a linear time invariant system. Using an oscillating pressure pattern and linear system identification methods, C (out) and PVI with confidence intervals, were estimated in real-time. Forty-two OPI and constant pressure infusion (CPI) investigations were performed on an experimental CSF system, designed with PVI = 25.5 ml and variable C (out). The ARX model robustly estimated C (out) (mean C (out,OPI) - C (out,CPI) = 0.08 μl/(s kPa), n = 42, P = 0.68). The Box-Jenkins model proved most reliable for PVI (23.7 ± 2.0 ml, n = 42). The OPI method, with its oscillating pressure pattern and new parameter estimation methods, efficiently estimated C (out) and PVI as well as their confidence intervals in real-time. The results from this experimental study show potential for the OPI method and supports further evaluation in a clinical setting.

  • 92.
    Andersson, Kennet
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Suhr, Ole B.
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Medicin.
    Faes, Luca
    Wiklund, Urban
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Directed coherence analysis in patients with severe autonomic dysfunction2014Inngår i: 2014 8th conference of the European Study Group on Cardiovascular Oscillations (ESGCO), IEEE conference proceedings, 2014, s. 167-168Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Many different approaches have been applied to analyse the coupling between cardiovascular signals. This study evaluated the use of directed coherence, based on multivariate autoregressive modelling, for analysis of cardiovascular signals in patients with transthyretin amyloidosis, a rare disease where severe autonomic dysfunction is common.

  • 93.
    Andersson, Kennet
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Sundström, Nina
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Malm, Jan
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Eklund, Anders
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Effect of resting pressure on the estimate of cerebrospinal fluid outflow conductance2011Inngår i: Fluids and barriers of the CNS, ISSN 2045-8118, Vol. 8, nr 1, s. 15-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    BACKGROUND: A lumbar infusion test is commonly used as a predictive test for patients with normal pressure hydrocephalus and for evaluation of cerebrospinal fluid (CSF) shunt function. Different infusion protocols can be used to estimate the outflow conductance (Cout) or its reciprocal the outflow resistance, (Rout) with or without using the baseline resting pressure, Pr. Both from a basic physiological research and a clinical perspective, it is important to understand the limitations of the model on which infusion tests are based. By estimating Cout using two different analyses, with or without Pr, the limitations could be explored. The aim of this study was to compare the Cout estimates, and investigate what effect Pr had on the results.

    METHODS: Sixty-three patients that underwent a constant pressure infusion protocol as part of their preoperative evaluation for normal pressure hydrocephalus, were included (age 70.3+/-10.8 years (mean +/-SD). The analysis was performed without (Cexcl Pr) and with (Cincl Pr) Pr. The estimates were compared using Bland-Altman plots and paired sample t-tests (p<0.05 considered significant).

    RESULTS: Mean Cout for the 63 patients was: Cexcl Pr = 7.0+/-4.0 (mean +/-SD) ul/(s kPa) and Cincl Pr = 9.1+/-4.3 ul/(s kPa) and Rout was 19.0+/-9.2 and 17.7+/-11.3 mmHg/ml/min, respectively. There was a positive correlation between methods (r=0.79, n=63, p<0.01). The difference, DeltaCout, -2.1+/-2.7 ul/(s kPa) between methods was significant (p<0.01) and DeltaRout was 1.2 +/- 8.8 mmHg/ml/min). The Bland-Altman plot visualized that the variation around the mean difference was similar all through the range of measured values and there was no correlation between DeltaCout and Cout.

    CONCLUSIONS: The difference between Cout estimates, obtained from analyses with or without Pr, needs to be taken into consideration when comparing results from studies using different infusion test protocols. The study suggests variation in CSF formation rate, variation in venous pressure or a pressure dependent Cout as possible causes for the deviation from the CSF absorption model seen in some patients.

  • 94.
    Andersson, Linus
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi. Department of Occupational and Public Health Sciences, University of Gävle, Sweden.
    Claeson, Anna-Sara
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB). Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Nordin, Steven
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Short-term olfactory sensitization involves brain networks relevant for pain, and indicates chemical intolerance2017Inngår i: International journal of hygiene and environmental health (Print), ISSN 1438-4639, E-ISSN 1618-131X, Vol. 220, nr 2, s. 503-509Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Chemical intolerance is a medically unexplained affliction that implies deleterious reactions to non-toxic everyday chemical exposure. Sensitization (i.e. increased reactivity to repeated, invariant stimulation) to odorous stimulation is an important component in theoretical explanations of chemical intolerance, but empirical evidence is scarce. We hypothesized that (1) individuals who sensitize to repeated olfactory stimulation, compared with those who habituate, would express a lower blood oxygenated level dependent (BOLD) response in key inhibitory areas such as the rACC, and higher signal in pain/saliency detection regions, as well as primary and/or secondary olfactory projection areas; and (2) olfactory sensitization, compared with habituation, would be associated with greater self-reported chemical intolerance. More-over, we assessed whether olfactory sensitization was paralleled by comparable trigeminal processing - in terms of perceptual ratings and BOLD responses. We grouped women from a previous functional magnetic imaging study based on intensity ratings of repeated amyl acetate exposure over time. Fourteen women sensitized to the exposure, 15 habituated, and 20 were considered "intermediate" (i.e. neither sensitizers nor habituaters). Olfactory sensitizers, compared with habituaters, displayed a BOLD-pattern in line with the hypothesis, and reported greater problems with odours in everyday life. They also expressed greater reactions to CO2 in terms of both perceived intensity and BOLD signal. The similarities with pain are discussed.

  • 95.
    Andersson, Linus
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Claesson, Anna-Sara
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB), Fysiologi. Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi.
    Stenberg, Berndt
    Umeå universitet, Medicinska fakulteten, Institutionen för folkhälsa och klinisk medicin, Dermatologi och venereologi.
    Nordin, Steven
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Brain responses to olfactory and trigeminal exposure in idiopathic environmental illness (IEI) attributed to smells: An fMRI study2014Inngår i: Journal of Psychosomatic Research, ISSN 0022-3999, E-ISSN 1879-1360, Vol. 77, nr 5, s. 401-408Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    OBJECTIVE: Idiopathic environmental intolerance (IEI) to smells is a prevalent medically unexplained illness. Sufferers attribute severe symptoms to low doses of non-toxic chemicals. Despite the label, IEI is not characterized by acute chemical senses. Theoretical models suggest that sensitized responses in the limbic system of the brain constitute an important mechanism behind the symptoms. The aim was to investigate whether and how brain reactions to low-levels of olfactory and trigeminal stimuli differ in individuals with and without IEI. METHODS: Brain responses to intranasally delivered isoamyl acetate and carbon dioxide were assessed in 25 women with IEI and 26 non-ill controls using functional magnetic resonance imaging. RESULTS: The IEI group had higher blood-oxygenated-level-dependent (BOLD) signal than controls in the thalamus and a number of, mainly, parietal areas, and lower BOLD signal in the superior frontal gyrus. The IEI group did not rate the exposures as more intense than the control group did, and there were no BOLD signal differences between groups in the piriform cortex or olfactory regions of the orbitofrontal cortex. CONCLUSIONS: The IEI reactions were not characterized by hyper-responsiveness in sensory areas. The results can be interpreted as a limbic hyperreactivity and speculatively as an inability to inhibit salient extemal stimuli.

  • 96. Andersson, M.
    et al.
    Johansson, Lennart
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Minarik, D.
    Mattsson, S.
    Leide-Svegborn, S.
    Absorbed dose to the urinary bladder wall for different radiopharmaceuticals using dynamic S-values2013Inngår i: European Journal of Nuclear Medicine and Molecular Imaging, ISSN 1619-7070, E-ISSN 1619-7089, Vol. 40, nr Supplement 2, s. S161-S161Artikkel i tidsskrift (Annet vitenskapelig)
  • 97. Andersson, M.
    et al.
    Johansson, Lennart
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Minarik, D.
    Mattsson, S.
    Leide-Svegborn, S.
    An internal radiation dosimetry computer program, IDAC 2.0, for estimation of patient doses from radiopharmaceuticals2014Inngår i: Radiation Protection Dosimetry, ISSN 0144-8420, E-ISSN 1742-3406, Vol. 162, nr 3, s. 299-305Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The internal dosimetry computer program internal dose assessment by computer (IDAC) for calculations of absorbed doses to organs and tissues as well as effective doses to patients from examinations with radiopharmaceuticals has been developed. The new version, IDAC2.0, incorporates the International Commission on Radiation Protection (ICRP)/ICRU computational adult male and female voxel phantoms and decay data from the ICRP publication 107. Instead of only 25 source and target regions, calculation can now be made with 63 source regions to 73 target regions. The major advantage of having the new phantom is that the calculations of the effective doses can be made with the latest tissue weighting factors of ICRP publication 103. IDAC2.0 uses the ICRP human alimentary tract (HAT) model for orally administrated activity and for excretion through the gastrointestinal tract and effective doses have been recalculated for radiopharmaceuticals that are orally administered. The results of the program are consistent with published data using the same specific absorption fractions and also compared with published data from the same computational phantoms but with segmentation of organs leading to another set of specific absorption fractions. The effective dose is recalculated for all the 34 radiopharmaceuticals that are administered orally and has been published by the ICRP. Using the new HAT model, new tissue weighting factors and the new adult computational voxel phantoms lead to an average effective dose of half of its earlier estimated value. The reduction mainly depends on electron transport simulations to walled organs and the transition from the stylised phantom with unrealistic interorgan distances to more realistic voxel phantoms.

  • 98. Andersson, M.
    et al.
    Johansson, Lennart
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Minarik, D.
    Mattsson, S.
    Leide-Svegborn, S.
    IDAC2.0 a new generation of internal dosimetric calculations for diagnostic examinations in nuclear medicine using the adult ICRP/ICRU reference computational voxel phantoms2013Inngår i: European Journal of Nuclear Medicine and Molecular Imaging, ISSN 1619-7070, E-ISSN 1619-7089, Vol. 40, nr Supplement 2, s. S175-S176Artikkel i tidsskrift (Annet vitenskapelig)
  • 99. Andersson, M.
    et al.
    Minarik, D.
    Johansson, Lennart
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Mattsson, S.
    Leide-Svegborn, S.
    A new method to generate dose coefficients for the source region "other organs and tissues"2014Inngår i: European Journal of Nuclear Medicine and Molecular Imaging, ISSN 1619-7070, E-ISSN 1619-7089, Vol. 41 2, s. S237-S237Artikkel i tidsskrift (Annet vitenskapelig)
  • 100.
    Andersson, Magnus
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Fällman, Erik
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Hedman, Håkan
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper.
    Axner, Ove
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Model System for in Situ Investigation of Binding Strengths of Integrin Mediated Cellular Adhesion2003Inngår i: World congress on medical physics and biomedical engineering, 2003Konferansepaper (Annet vitenskapelig)
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