نتایج جستجو برای: computed tomography tube current modulation patient dose
تعداد نتایج: 2107551 فیلتر نتایج به سال:
PURPOSE To compare radiation dose and image quality using predefined narrow phase window versus complete phase window with dose modulation during R-R using 320-row MDCTA. METHODS 114 patients underwent coronary CTA study using 320-row MDCT scanner. 87 patients with mean age (61 + 13 years), mean BMI (29 + 6), and mean heart rate (HR) (58 + 7 bpm) were imaged at predefined 66-80% R-R interval ...
Introduction Objective: This study aims to investigate the reduction of radiation dose in cerebral CT perfusion by lower low-tube current. Material and methods Two hundred patients, who underwent non-contrast computed tomography (CT) perfusion, were randomized into four groups according tube current contrast media (CM) concentration: group A (60 mAs, 320 mgI/ml), B 370 C (100 D mgI/ml). Among t...
The objective of this study was to investigate the impact of image acquisition settings and patients' characteristics on image quality and radiation dose for coronary angiography by 320-row computed tomography (CT). CORE320 is a prospective study to investigate the diagnostic performance of 320-detector CT for detecting coronary artery disease and associated myocardial ischemia. A run-in phase ...
We evaluated the effectiveness of metallic shields that were used for reduction of the breast dose in thoracic computed tomography(CT). For the evaluation, we measured breast surface dose and image standard deviation(SD)in the lung area. The metallic shields were made from bismuth, zinc, copper, and iron. The bismuth shield has been marketed and used for dose reduction. The other three metallic...
Automatic exposure control (AEC) in computed tomography (CT) facilitates optimisation of dose absorbed by the patient. The use of AEC requires appropriate 'patient centring' within the gantry, since positioning the patient off-centre may affect both image quality and absorbed dose. The aim of this experimental study was to measure the variation in organ and abdominal surface dose during CT exam...
Background and purpose: Radiation therapy as a part of cancer treatment is used in almost 50-60% of involved cases. In prostate cancer radiation therapy, a large volume of pelvis is irradiated, so, it is necessary to preserve sensitive organs around the treatment area, especially rectum and bladder. In this study, some dosimetric parameters such as minimum dose (Dmin), maximum dose (Dmax), mean...
Background: Breast cancer is a common disease in radiation oncology. We evaluated the radiation dose received by breast cancer patients, an often-neglected concern. Materials and Methods: The total effective radiation dose in 101 breast cancer patients was calculated by summing the effective doses of individual diagnostic imaging tests from the first hospital visit to the initiation of radiothe...
Digital tomosynthesis is a radiographic technique that can produce an arbitrary number of section images of a patient from a single pass of the X-ray tube. It utilizes a conventional X-ray tube, a flat-panel detector, a computer-controlled tube mover, and special reconstruction algorithms to produce section images. While it does not have the depth resolution of computed tomography (CT), tomosyn...
BACKGROUND Medical X-rays are the largest man-made source of public exposure to ionizing radiation. While the benefits of Computed Tomography (CT) are well known in accurate diagnosis, those benefits are not risk-free. CT is a device with higher patient dose in comparison with other conventional radiation procedures. OBJECTIVE This study is aimed at evaluating radiation dose to patients from ...
After over one decade development, cone beam computed tomography (CBCT) has been widely accepted for clinical application in almost every field of dentistry. Meanwhile, the radiation dose of CBCT to patient has also caused broad concern. According to the literature, the effective radiation doses of CBCTs in nowadays market fall into a considerably wide range that is from 19 µSv to 1073 µSv and ...
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