نتایج جستجو برای: breast average dose
تعداد نتایج: 907628 فیلتر نتایج به سال:
Introduction: Delivering maximum dose to tumor and minimum dose to normal tissues is the most important goal in radiotherapy. According to ICRU, the maximum acceptable uncertainty in the delivered dose compared to the prescribed dose should be lower than 5%, and this is because of the relationship between absorbed dose, tumor control and normal tissue damage. Absorbed dose accuracy is investiga...
PURPOSE To evaluate two different techniques for whole-breast treatments delivered using the Hi-ART II tomotherapy device. METHODS AND MATERIALS Tomotherapy uses the standard rotational helical delivery. Topotherapy uses a stationary gantry while delivering intensity-modulated treatments. CT scans from 5 breast cancer patients were used. The prescription dose was 50.4 Gy. RESULTS On average...
background: to reduce the dose to normal tissues surrounding the treated breast, a uniform magnetic field was used within a humanoid phantom in breast radiotherapy. materials and methods: monte carlo simulations were performed with geant4, irradiating humanoid phantoms in a magnetic field. to reconstruct phantoms, computed tomography (ct) data slices of four patients were used for the monte car...
PURPOSE The aim of this study was to assess the feasibility and advantages of a patient-specific breast bolus made using a 3D printer technique. METHODS We used the anthropomorphic female phantom with breast attachments, which volumes are 200, 300, 400, 500 and 650 cc. We simulated the treatment for a right breast patient using parallel opposed tangential fields. Treatment plans were used to ...
In this study the contralateral breast skin dose was decreased. It was to apply the results to the clinical study after analysis of different radiation dose amounts to contralateral breast with nonmagnetic bolus and without nonmagnetic bolus. A Rando phantom was computed tomography (CT) simulated, five treatment plans were generated: open tangents, open field in field, wedge 15, wedge 30, and i...
BACKGROUND Today it is unclear which technique for delivery of an additional boost after whole breast radiotherapy for breast conserved patients should be state of the art. We present a dosimetric comparison of different non-invasive treatment techniques for additional boost delivery. METHODS For 10 different tumor bed localizations, 7 different non-invasive treatment plans were made. Dosimet...
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: This paper presents a method to reduce radiation exposure during mammography by analysing the doses to ipsilateral and contralateral breasts and to adjacent organs by evaluating material-dependent shielding performance. Materials and Methods: Six target-filter combinations (Mo-Mo, Mo-Rh, Rh-Rh, Rh-Mo, W-Mo, W-Rh) were tested by measuring the doses delivered to the breasts and adjac...
background: the exposure of human being to ionize radiation from natural sources is a continuing, inescapable feature of life on earth. direct measurement of absorbed dose rates in air has been carried out in many countries of the world during the last few decades. such investigations can be useful for assessment of public dose rates, the performance of epidemiological studies, and keeping refe...
PURPOSE To evaluate the dosimetric impact of source-positioning uncertainty in high-dose-rate (HDR) balloon brachytherapy of breast cancer. MATERIAL AND METHODS For 49 HDR balloon patients, each dwell position of catheter(s) was manually shifted distally (+) and proximally (-) with a magnitude from 1 to 4 mm. Total 392 plans were retrospectively generated and compared to corresponding clinica...
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