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- Glimelius, Bengt, et al.
(author)
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A systematic overview of radiation therapy effects in rectal cancer.
- 2003
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In: Acta oncologica (Stockholm, Sweden). - : Informa UK Limited. - 0284-186X .- 1651-226X. ; 42, s. 476-
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Journal article (peer-reviewed)abstract
- A systematic review of radiation therapy trials in several tumour types was performed by The Swedish Council of Technology Assessment in Health Care (SBU). The procedures for evaluation of the scientific literature are described separately (Acta Oncol 2003; 42: 357-365). This synthesis of the literature on radiation therapy for rectal cancer is based on data from 42 randomized trials and 3 meta-analyses. Moreover, data from 36 prospective studies, 7 retrospective studies and 17 other articles were used. A total of 131 scientific articles are included, involving 25 351 patients. The results were compared with those of a similar overview from 1996 including 15 042 patients. The conclusions reached can be summarized thus: The results after rectal cancer surgery have improved during the past decade. It is likely that local failure rates after 5 years of follow-up at hospitals adopting the TME-concept (TME = total mesorectal excision) have decreased from about 28% to 10-15%. Preoperative radiotherapy at biological effective doses above 30 Gy decreases the relative risk of a local failure by more than half (50-70%). Postoperative radiotherapy decreases the risk by 30-40% at doses that generally are higher than those used preoperatively. There is strong evidence that preoperative radiotherapy is more effective than postoperative. There is moderate evidence that preoperative radiotherapy significantly decreases the local failure rate (from 8% to 2% after 2 years) also with TME. There is strong evidence that preoperative radiotherapy improves survival (by about 10%). There is no evidence that postoperative radiotherapy improves survival. There is some indication that survival is prolonged when postoperative radiotherapy is combined with concomitant chemotherapy. Preoperative radiotherapy at adequate doses can be given with low acute toxicity. Higher, and unacceptable acute toxicity has been seen in some preoperative radiotherapy trials using suboptimal techniques. Postoperative radiotherapy can also be given with acceptable acute toxicity. The long-term consequences of radiotherapy appear to be limited with adequate radiation techniques, although they have been less extensively studied. Longer follow-up periods are needed before firm conclusions can be drawn. Peroperative radiotherapy, preferably preoperative since it is more effective, is routinely recommended for most patients with rectal cancer since it can substantially decrease the risk of a local failure and increases survival. In a primarily non-resectable tumour, preoperative radiotherapy can cause tumour regression allowing subsequent radical surgery. This therapy is routinely indicated. Whether radiochemotherapy is more efficient than radiotherapy alone is not clear, since the results of four small randomized trials are partly conflicting. Preoperative radiotherapy, frequently combined with chemotherapy, has been used to increase the chances of sphincter-preserving surgery in low-lying tumours. The literature is inconclusive with respect to how frequently this occurs. Radiotherapy frequently produces symptom relief in patients with rectal cancer not amendable to surgery.
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| 2. |
- Lango Allen, Hana, et al.
(author)
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Hundreds of variants clustered in genomic loci and biological pathways affect human height.
- 2010
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In: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 467:7317, s. 832-8
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Journal article (peer-reviewed)abstract
- Most common human traits and diseases have a polygenic pattern of inheritance: DNA sequence variants at many genetic loci influence the phenotype. Genome-wide association (GWA) studies have identified more than 600 variants associated with human traits, but these typically explain small fractions of phenotypic variation, raising questions about the use of further studies. Here, using 183,727 individuals, we show that hundreds of genetic variants, in at least 180 loci, influence adult height, a highly heritable and classic polygenic trait. The large number of loci reveals patterns with important implications for genetic studies of common human diseases and traits. First, the 180 loci are not random, but instead are enriched for genes that are connected in biological pathways (P = 0.016) and that underlie skeletal growth defects (P<0.001). Second, the likely causal gene is often located near the most strongly associated variant: in 13 of 21 loci containing a known skeletal growth gene, that gene was closest to the associated variant. Third, at least 19 loci have multiple independently associated variants, suggesting that allelic heterogeneity is a frequent feature of polygenic traits, that comprehensive explorations of already-discovered loci should discover additional variants and that an appreciable fraction of associated loci may have been identified. Fourth, associated variants are enriched for likely functional effects on genes, being over-represented among variants that alter amino-acid structure of proteins and expression levels of nearby genes. Our data explain approximately 10% of the phenotypic variation in height, and we estimate that unidentified common variants of similar effect sizes would increase this figure to approximately 16% of phenotypic variation (approximately 20% of heritable variation). Although additional approaches are needed to dissect the genetic architecture of polygenic human traits fully, our findings indicate that GWA studies can identify large numbers of loci that implicate biologically relevant genes and pathways.
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| 3. |
- Palmberg, Lars Johan, 1713-1804
(author)
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Dissertatio academica, de antiquitatum scientia, cujus partem tertiam, adprobante ampliss. facultate philosophica, in regia academia Upsaliensi, publicæ bonorum censuræ committunt auctor, ... Laur. J. Palmberg, ... et respondens, Johannes Grönberg, Stockholmiensis. In auditorio Gustav. minor. Die XXVII. maji, anni MDCCLXXVIII. ... ., P. 3
- 1778
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Doctoral thesis (other academic/artistic)
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| 4. |
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| 5. |
- Tehrani, Sara S.M., et al.
(author)
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Iodine K-edge imaging in photon counting CT through multiple two-basis decompositions and deep learning
- 2024
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In: Medical Imaging 2024: Physics of Medical Imaging. - : SPIE-Intl Soc Optical Eng.
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Conference paper (peer-reviewed)abstract
- One advantage of photon-counting CT compared to dual-energy CT is the possibility to perform K-edge imaging, where contrast agents such as iodine can be distinguished from other substances based on spectral characteristics. However, for iodine K-edge imaging in clinical CT, the three-basis decomposition problem is ill-conditioned due to the low K-edge energy of iodine, meaning that the decomposition is highly sensitive to both noise and miscalibrations. This makes robust three-basis decomposition difficult using standard techniques. In this simulation study we evaluate a novel method of performing K-edge imaging, which circumvents the challenging three-basis decomposition step by replacing it with multiple two-basis decompositions followed by a deep convolutional neural network to generate three basis images. Based on the XCAT phantom, we generated 1224 spectral phantom image slices of the neck, with iodine-filled blood vessels and calcifications, and simulated CT imaging in CatSim with a silicon-based detector model without quantum noise, i.e. in the high-dose limit. For each simulated slice, we used maximum likelihood to perform three two-basis decompositions, into PE-PVC, PE-iodine, and PVC-iodine, yielding six basis images in total. We then trained a U-Net to map these six input images to the ground-truth basis images, PE, PVC and iodine. Our results show that the proposed method can reproduce PE, PVC and iodine basis images with high accuracy, in the high-dose limit. This suggests that the proposed three-basis decomposition method may be a feasible way of performing K-edge CT imaging with iodine, with important potential implications for imaging of the carotid arteries.
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