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- Emerging Risk Factors, Collaboration, et al.
(författare)
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The Emerging Risk Factors Collaboration: analysis of individual data on lipid, inflammatory and other markers in over 1.1 million participants in 104 prospective studies of cardiovascular diseases
- 2007
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Ingår i: Eur J Epidemiol. - 0393-2990. ; 22:12, s. 839-69
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Tidskriftsartikel (refereegranskat)abstract
- Many long-term prospective studies have reported on associations of cardiovascular diseases with circulating lipid markers and/or inflammatory markers. Studies have not, however, generally been designed to provide reliable estimates under different circumstances and to correct for within-person variability. The Emerging Risk Factors Collaboration has established a central database on over 1.1 million participants from 104 prospective population-based studies, in which subsets have information on lipid and inflammatory markers, other characteristics, as well as major cardiovascular morbidity and cause-specific mortality. Information on repeat measurements on relevant characteristics has been collected in approximately 340,000 participants to enable estimation of and correction for within-person variability. Re-analysis of individual data will yield up to approximately 69,000 incident fatal or nonfatal first ever major cardiovascular outcomes recorded during about 11.7 million person years at risk. The primary analyses will involve age-specific regression models in people without known baseline cardiovascular disease in relation to fatal or nonfatal first ever coronary heart disease outcomes. This initiative will characterize more precisely and in greater detail than has previously been possible the shape and strength of the age- and sex-specific associations of several lipid and inflammatory markers with incident coronary heart disease outcomes (and, secondarily, with other incident cardiovascular outcomes) under a wide range of circumstances. It will, therefore, help to determine to what extent such associations are independent from possible confounding factors and to what extent such markers (separately and in combination) provide incremental predictive value.
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| 2. |
- Edvardsson, A., et al.
(författare)
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Breathing-motion induced interplay effects for stereotactic body radiotherapy of liver tumours using flattening-filter free volumetric modulated arc therapy
- 2019
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 0031-9155 .- 1361-6560. ; 64:2
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to investigate breathing-motion induced interplay effects for stereotactic body radiotherapy (SBRT) of liver tumours treated with flattening-filter free (FFF) volumetric modulated arc therapy (VMAT). Ten patients previously treated with liver SBRT were included in this study. All patients had four-dimensional computed tomography (4DCT) scans acquired prior to treatment. The 4DCT was sorted into 8-10 phases covering an equal time interval. A FFF VMAT plan was created for one fraction in the mid-ventilation phase for each patient. To generate dose distributions including both interplay effects and dose blurring, a sub-plan was calculated for each phase. The total dose distributions were accumulated to the mid-ventilation phase using the deformed vector fields (DVF) from deformable image registration between the corresponding CT and the mid-ventilation phase CT. A blurred dose distribution, not including interplay effects, was also obtained by distributing the delivery of the whole plan uniformly on all phases, and was similarly accumulated to the mid-ventilation phase. To isolate interplay effects, this blurred dose distribution was subtracted from the total dose distribution with interplay effects. The near minimum dose (D-98%), mean dose (D-mean), heterogeneity index (HI), and the near minimum dose difference (Delta D-98%) between the accumulated dose distributions with and without interplay effects were calculated within the gross tumour volume (GTV) for each patient. Comparing the accumulated dose distributions with and without interplay effects, the D-98(%) decreased for nine of the ten patients and the HI increased for all patients. The median and minimum differences in D-98(%) were -2.1% and -5.0% (p = 0.006), respectively, and the median HI significantly increased from 6.2% to 12.2% (p = 0.002). The median Delta D-98% was -4.0% (range - 7% to - 1.5%). In conclusion, statistically significant breathing-induced interplay effects were observed for a single fraction of FFF VMAT liver SBRT, resulting in heterogeneous dose distributions within the GTV.
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| 3. |
- Nilsson, M. P., et al.
(författare)
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Dosimetric and Clinical Predictors for Acute and Late Gastrointestinal Toxicity Following Chemoradiotherapy of Locally Advanced Anal Cancer
- 2022
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Ingår i: Clinical Oncology. - : Elsevier BV. - 0936-6555. ; 34:1, s. 35-44
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Tidskriftsartikel (refereegranskat)abstract
- Aims: To analyse dosimetric and clinical predictors for acute and late gastrointestinal toxicity following chemoradiotherapy of anal cancer. Materials and methods: Consecutive patients with locally advanced (T2 ≥4 cm – T4 or N+) anal cancer were selected from an institutional database (n = 114). All received intensity-modulated radiotherapy with concomitant 5-fluorouracil and mitomycin C. Gastrointestinal toxicity was retrospectively graded according to Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 and bowel cavity, small bowel and large bowel were contoured. Dosimetric and clinical variables were tested for associations with acute grade ≥3 gastrointestinal toxicity and late grade ≥2 gastrointestinal toxicity using the Mann–Whitney test, area under receiver operating characteristic curve (AUC) and logistic regression. Results: The median follow-up was 40 months. Acute grade ≥3 gastrointestinal toxicity was seen in 51 (44.7%) of the patients; late grade ≥2 gastrointestinal toxicity was seen in 36 of the patients (39.6% of 91 patients with >1 year recurrence-free follow-up). Bowel cavity V30Gy was the best dosimetric predictor for acute gastrointestinal toxicity (AUC 0.633; P = 0.02). Large bowel V20Gy was the best dosimetric predictor for late gastrointestinal toxicity (AUC 0.698; P = 0.001) but showed no association with acute gastrointestinal toxicity. In multivariate logistic regression, increasing age was significantly associated with acute gastrointestinal toxicity; smoking and large bowel V20Gy were significantly associated with late gastrointestinal toxicity. Patients who experienced acute grade ≥3 gastrointestinal toxicity were not at an increased risk of late grade ≥2 gastrointestinal toxicity (odds ratio 1.3; P = 0.55). Conclusions: Factors of importance for acute and late gastrointestinal toxicity were not the same. Bowel cavity V30Gy is a good metric to use for the prediction of acute gastrointestinal toxicity, but the results of our study indicate that individual large and small bowel loops need to be contoured for better prediction of late gastrointestinal toxicity. The role of the large bowel as an important organ at risk for late gastrointestinal toxicity merits further research.
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| 5. |
- Scherman Rydhög, Anna, et al.
(författare)
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Intravoxel Incoherent Motion (IVIM) Imaging at Different Magnetic Field Strengths: What is Feasible?
- 2014
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Ingår i: Magnetic Resonance Imaging. - : Elsevier BV. - 1873-5894 .- 0730-725X. ; 32:10, s. 1247-1258
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Tidskriftsartikel (refereegranskat)abstract
- Due to limited SNR the cerebral applications of the intravoxel incoherent motion (IVIM) concept have been sparse. MRI hardware developments have resulted in improved SNR and this may justify a reassessment of IVIM imaging for non-invasive quantification of the cerebral blood volume (CBV) as a first step towards determining the optimal field strength.
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| 6. |
- Stervik, Louise, 1993, et al.
(författare)
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Modelling the risk of fatal acute toxicity following radiotherapy of lung cancer
- 2018
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Ingår i: Physica medica. Vol. 52, Suppl. 1, p. 30. 2nd European Congress of Medical Physics. - : Elsevier BV. - 1120-1797 .- 1724-191X.
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Konferensbidrag (refereegranskat)abstract
- Purpose:To model the risk of fatal acute toxicity after conventionally fractionated curative radiotherapy of patients with non-small-cell lung cancer (NSCLC). Methods:Scripting was used to automatically extract treatment-related data for all patients treated for NSCLC between 2008 and 2016 from three hospitals. Inclusion criteria were conventionally fractionated curative radiotherapy and no prior treatment in the thorax region. Maximum likelihood estimation and logistic regression (LR) were used to model the risk of fatal acute toxicity defined as death within 90 days from treatment start. Mean lung dose (MLD), patient age and the volume of the gross tumour volume (GTV) were investigated as predictors in a univariable LR analysis. We performed analysis on the data from the three hospitals separately and merged. Predictor variables were considered statistically significant if p < 0.05. All predictor variables with a p < 0.1 were further analysed in multivariable LR models. Confidence intervals (CIs) for the predictors were calculated using the likelihood ratio test. CIs for the multivariable models were calculated by bootstrapping. Results:Data was extracted for 848 patients. The incidence of death within 90 days from treatment start was 3.8% (32/848) for the merged data set and varied from 1.8% to 5.4% between hospitals. For the hospital with the highest incidence, a statistically significant relationship between MLD and the risk of fatal acute toxicity (p = 0.020) was found. The model parameters and their 95% CIs were D50=42.8 (31.4-167.7) Gy and γ50=1.20 (0.77-1.68). In the univariable LRs with patient age and GTV volume, patient age had p-values < 0.1 and GTV volume p-values > 0.2. Multivariable LR with MLD and patient age resulted in a statistically significant multivariable model (p = 0.005) for the merged data. The calculated risks and their 95% CIs for a patient with MLD = 20 Gy were 1.6% (0.5-3.3%), 2.8% (1.3-4.5%), 4.9% (3.1-6.8%), and 8.6% (4.8-13.5%) at 50, 60, 70, and 80 years of age, respectively. Conclusions:A statistically significant multivariable model quantifying the risk of fatal acute toxicity with MLD and patient age as predictor variables was found.
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