نتایج جستجو برای: ray ct dose
تعداد نتایج: 689623 فیلتر نتایج به سال:
BACKGROUND Hybrid imaging combines nuclear medicine imaging such as single photon emission computed tomography (SPECT) or positron emission tomography (PET) with computed tomography (CT). Through this hybrid design, scanned patients accumulate radiation exposure from both applications. Imaging modalities have been the subject of long-term optimization efforts, focusing on diagnostic application...
In a repeated radiotherapy owing to a local recurrence close to the previous irradiation, the dose distribution of next irradiation is required to avoid overlap with previous one. Therefore, a system for displaying dose-distribution image of previous irradiation on a present anatomical image would be helpful in designing new radiotherapy. However, registration of two abdominal CT images acquire...
The purpose of this study is to survey the current patterns of practice, and barriers to implementation, of 3D image-guided brachytherapy (3D-IGBT) for cervical cancer in Japan. A 30-item questionnaire was sent to 171 Japanese facilities where high-dose-rate brachytherapy devices were available in 2012. In total, 135 responses were returned for analysis. Fifty-one facilities had acquired some s...
Sub-fossilised remains may still contain highly degraded ancient DNA (aDNA) useful for palaeogenetic investigations. Whether X-ray computed [micro-] tomography ([μ]CT) imaging of these fossils may further damage aDNA remains debated. Although the effect of X-ray on DNA in living organisms is well documented, its impact on aDNA molecules is unexplored. Here we investigate the effects of synchrot...
Plain x-rays can reveal opaque renal calculi. They may also be helpful in nephrocalcinosis where there is increased uptake of calcium by the kidneys. CT scan of kidneys, ureter and bladder is the preferred imaging modality looking for renal calculi. CT scanning has a higher radiation dose than plain x-ray but it has a much better sensitivity for detecting a stone both directly and indirectly (e...
AIMS AND BACKGROUND "Augmented reality" is a technique to create a composite view by augmenting the real intervention field, visualized by the doctor, with additional information coming from a virtual volume generated using computed tomography (CT), magnetic resonance or ultrasound images previously acquired from the same patient. In the present study we verified the accuracy and validated the ...
background: this study presents patient specific and organ dose estimation in computed tomography (ct) imaging of thorax directly from patient ct image using monte carlo simulation. patient's ct image is considered as the patient specific phantom and the best representative of patient physical index in order to calculate specific organ dose. materials and methods: egsnrc /beamnrc monte c...
Overexposures in computed tomography: In several institutions, overexposures have occurred during use of x-ray computed tomography (CT) for brain perfusion studies to identify 10 the neurological consequences of strokes and other events. In some cases, patients received exposures that were several times greater than necessary. The overexposures were caused by use of inappropriate CT protocols f...
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