نتایج جستجو برای: ct scan absorb dose thyroid shielding dose reduction
تعداد نتایج: 1024960 فیلتر نتایج به سال:
Introduction: Due to the use of ionizing radiation in the CT scan, optimal parameters should be used to reduce the risk of cancer in patients who are constantly exposed to X-rays. The aim of this study was to optimize the parameters used in CT scan of cervical vertebrae and neck soft tissue with minimal loss of image quality Materials and Methods: In this s...
in present pet/ct scanners, pet attenuation correction is performed by relying on the information given by ct scan. in the ct-based attenuation correction methods, dual-energy technique (dect) is the most accurate approach, which has been limited due to the increasing patient dose. in this feasibility study, we have introduced a new method that can implement dual-energy technique with only a si...
OBJECTIVE To assess the breast dose during a routine thoracic cone-beam CT (CBCT) check with the efforts to explore the possible dose reduction strategy. MATERIALS AND METHODS Metal oxide semiconductor field-effect transistor (MOSFET) dosimeters were used to measure breast surface doses during a thorax kV CBCT scan in an anthropomorphic phantom. Breast doses for different scanning protocols a...
The purpose of this work is to compare different methods for shielding calculation in computed tomography (CT). The BIR-IPEM (British Institute of Radiology and Institute of Physics in Engineering in Medicine) and NCRP (National Council on Radiation Protection) method were used for shielding thickness calculation. Scattered dose levels and calculated barrier thickness were also compared with th...
OBJECTIVE To assess the cancer risk in children and adolescents following exposure to low dose ionising radiation from diagnostic computed tomography (CT) scans. DESIGN Population based, cohort, data linkage study in Australia. COHORT MEMBERS: 10.9 million people identified from Australian Medicare records, aged 0-19 years on 1 January 1985 or born between 1 January 1985 and 31 December 2005;...
Head CT examinations may result in significant and unnecessary exposure to the lens of the eye. The International Commission of Radiological Protection (ICRP) has estimated the threshold for detectable opacities in the lens from a single brief exposure to be 0.5 2Gy and the threshold for visual impairment (cataract) to be 5Gy. The lens dose for sequential CT scanning of the brain with the orbit...
Nowadays medical imaging systems like PET/CT are widely used in cancer diagnosis. Due to serious and irreversible harms of ionization radiations, protection of all those who are exposed is the main concern of health issues. The main basis of the calculation of the shielding design in the medical imaging systems is that the absorbed dose should not exceed the allowed limit. Using the Monte Carl...
The purpose of this study was to determine the number of weekly acquisitions permissible using a mobile PET/SPECT scanner for myocardial perfusion/viability imaging in an intensive care unit (ICU) based on the effective dose to patients and staff. The effective dose to other patients and staff in an ICU was calculated following recommendations from the American Association of Physicists in Medi...
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