نتایج جستجو برای: glandular absorbed dose
تعداد نتایج: 332419 فیلتر نتایج به سال:
Introduction: Head scans are the most frequently performed computed tomography (CT) examinations worldwide. However, there is growing concern over the probability of increased cancer risks among the exposed populations. Diagnostic reference levels (DRLs) identify radiation dose that is not commensurate with clinical objectives. The aim of this study was to establish DR...
Introduction: Average glandular dose (AGD), entrance skin air kerma (ESAK) and normalized glandular dose (DgN) are the main dosimetric quantities in mammography. In this study, DgN is evaluated in the presence of breast cyst, which is a common disease among women and the influence of size, number and location of the cysts on the DgN is investigated. Materials and Meth...
For reasons of phantom material reproducibility, the absorbed dose protocols of the American Association of Physicists in Medicine (AAPM) (TG-51) and the International Atomic Energy Agency (IAEA) (TRS-398) have made the use of liquid water as a phantom material for reference dosimetry mandatory. In this work we provide a formal framework for the measurement of absorbed dose to water using ioniz...
introduction radiotherapy is regarded as the first treatment of choice for nasopharyngeal carcinoma. despite the advantages of radiotherapy, patients may suffer from a wide range of side-effects due to the presence of many sensitive normal tissues in these regions. if the absorbed dose exceeds the tolerance level in parotid glands and the spinal cord, myelopathy, lhermitte's sign and xeros...
The impact of digitalization on the average glandular doses in 49 mammographic units participating in the Flemish Breast Cancer Screening Program was studied. Screen-film was changed to direct digital radiography and computed radiography in 24 and 25 departments respectively. Average glandular doses were calculated before and after digitalization for different PMMAphantom thicknesses and for gr...
background: the purpose of this study was to find the accurate absorbed dose in the femur bone marrow during the x-ray radiography for constant mas and aec techniques. materials and methods: the dosxyznrc was used to simulate radiation doses in two human femurs during diagnostic radiography. egsnrc phantoms produced from actual ct images of human femurs were modified by adding seven micrometre ...
background: radiotherapy plays an important role in the management of most malignant and many benign primary central nervous system (cns) tumors. radiotherapy affects both tumor cells and uninvolved normal cells; so, it is important to estimate absorbed dose to organs at risk in this kind of treatment. the aim of this study was to determine the absorbed dose to chiasma, lens, optic nerve, retin...
background: human activities such as mining enhance the radioactivity levels above normal background which can lead to an incremental increase in the radiation risk to the population. materials and methods: 20 tailing enriched soil samples collected around maiganga coal mine, gombe, northeast nigeria were assessed for their 226ra, 232th and 40k contents using hpge gamma-ray detector. results: t...
background: the presence of radionuclides in the soil, measures need to be taken to minimize the radiation dose to humans. it is mostly gamma-emitting radionuclides that contribute to the radiation dose in long term behavior of these radionuclides in soil may determine the extent to which such countermeasures need to be applied. materials and methods: the activity concentration of these radionu...
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