نتایج جستجو برای: external radiation
تعداد نتایج: 420496 فیلتر نتایج به سال:
There has been analyzed hemoblastosis and leukemia morbidity in Siberian Group of Chemical Enterprises (SGCE) employees occupationally exposed to long-term low-level ionizing radiation. It has been found that hemoblastosis and leukemia morbidity in SGCE males is significantly higher as compared to the national and regional standards. The incidence rate in males is observed at the expense of non...
The sizes of the broad-line regions (BLRs) in γ-ray active galactic nuclei (AGNs) are estimated from their optical continuum luminosity by using the empirical relation between RBLR and Lλ,opt. Using the broad emission line data, we derive the photon energy density in the relativistic blobs near the massive black holes in AGNs. We calculate the power of the broad-line photons Compton up-scattere...
Successful delivery of conformal fields requires stringent immobilization and treatment verification, as well as knowledge of the setup reproducibility. [1] Before coming OBI, electronic portal imaging detector was used to detect the setup errors. EPID images are not clear vision to identify correctly and immediately because they were produced by megavoltage X-ray during treatment setup. In OBI...
This study investigates trends in perinatal mortality rates in Fukushima Prefecture and four neighboring prefectures (Miyagi, Gunma, Tochigi, and Ibaraki) before and after the Fukushima nuclear disaster in March 2011. Beginning in 2012, perinatal mortality rates deviate upwards from the trend in preceding years; the monthly data show significant peaks in May 2012 and March 2013. It is unlikely ...
PURPOSE This report describes the value of a voluntary error reporting system and the impact of a series of quality assurance (QA) measures including checklists and timeouts on reported error rates in patients receiving radiation therapy. METHODS AND MATERIALS A voluntary error reporting system was instituted with the goal of recording errors, analyzing their clinical impact, and guiding the ...
There are relatively few data on the risk of leukemia among those exposed to external radiation during cleanup operations after the Chornobyl nuclear accident, and results have not been consistent. To investigate this further, we assembled a cohort of 110,645 male cleanup workers from Ukraine and identified cases of leukemia occurring during the period 1986 to 2000. Detailed interviews were con...
The latter 2 decades of the last century have witnessed significant improvements in external beam radiotherapy (EBRT), moved primarily by the advances in imaging modalities and computer-based treatment planning. These advancements lead to introducing the addition of a fourth-dimension, time, to the three-dimensional geometry in EBRT. The new era in EBRT presents challenges and opportunities to ...
BACKGROUND During a fraction of external beam radiotherapy for prostate cancer, a mismatch between target volume and dose coverage may accumulate over time due to intra-fraction motion. One way to remove the residual error is to perform a couch shift in opposite direction. In principle, such couch shifts could cause secondary displacements of the patient and prostate. Hence it is interesting to...
Quality assessment in external beam radiotherapy necessitates for an efficient and robust tool for comparing the planned and realised geometry of the treatment. Such a tool using the modified Hausdorff distance measure has been developed and successfully introduced to clinical practice. The majority of steps of the method are automatic. The user specifies the share of edge data extracted from t...
The control of emission from localized light sources is an objective of outstanding relevance in nanophotonics. In a recent past, a large number of metallic nanostructures has been proposed to this end, wherein plasmonic modes are exploited as energy carriers on a subwavelength scale. As an interesting alternative, we present here the use of surface modes on patterned dielectric multilayers to ...
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