نتایج جستجو برای: radiotherapy dose calculations
تعداد نتایج: 468780 فیلتر نتایج به سال:
Grid-based deterministic dose-calculation methods for radiotherapy planning require the use of six-dimensional phase space grids. Because of the large number of phase space dimensions, a growing number of medical physicists appear to believe that grid-based deterministic dose-calculation methods are not competitive with Monte Carlo methods. We argue that this conclusion may be premature. Our re...
Introduction Wedge modifiers are commonly applied in external beam radiotherapy to change the dose distribution corresponding to the body contour and to obtain a uniform dose distribution within the target volume. Since the radiation dose delivered to the target must be within ±5% of the prescribed dose, accurate dose calculation by a treatment planning system (TPS) is important. The objective ...
BACKGROUND Patient-specific absorbed dose calculations for molecular radiotherapy require accurate activity quantification. This is commonly derived from Single-Photon Emission Computed Tomography (SPECT) imaging using a calibration factor relating detected counts to known activity in a phantom insert. METHODS A series of phantom inserts, based on the mathematical models underlying many clini...
UNLABELLED The purpose of the present study was to explore the outcome, cumulative dose in tumor and organs at risk and toxicity after extra-cranial stereotactic re-irradiation. Twenty-seven patients were evaluated who had been re-irradiated with stereotactic body radiotherapy (SBRT) after conventional radiotherapy (CRT). The dose summation of the SBRT and CRT plans was done by dose point calcu...
Background: Tangential irradiation of intact breast is one of the most common procedures performed in any radiotherapy center. This method is performed by using 2D and 3D treatment planning. The aim of this study was to compare 2D with 3D plans in breast conserving radiotherapy. Homogeneity of isodose, and lung received dose were compared. Materials and Methods: Twenty patients with br...
INTRODUCTION A sweeping beam technique for total body irradiation in standard treatment rooms and for standard linear accelerators (linacs) is introduced, which does not require any accessory attached to the linac. Lung shielding is facilitated to reduce the risk of pulmonary toxicity. Additionally, the applicability of a commercial radiotherapy planning system (RTPS) is examined. MATERIAL AN...
A retrospective analysis of 102 patients with relapsed, non-Hodgkin's lymphoma treated with two different ricin A chain-containing immunotoxins (ITs) in five Phase I clinical trials indicates that the dose-limiting toxicity, vascular leak syndrome, was more frequent and more severe in patients who had undergone prior radiotherapy (RT). Excluding patients with prior RT from the calculations of t...
introduction: intensity modulated radiation therapy (imrt) is one of the cancer treatment methods. it is important to selectively aim at the target in this way, which can be performed using a multileaf collimator (mlc). materials and methods: in order to specifically irradiate the target volume in radiotherapy to reduce the patient absorbed dose, the use of multileaf collimator has been investi...
Abstract Introduction: The accuracy an assessment of out- of- field dose due to secondary cancer risk is clinically important. Actually radiotherapy treatment planning systems are not commissioned for the out-of-field dose calculations, so the estimation of dose distributions by TPSs beyond the borders of treatment fields is not well calculate...
Introduction Accurate estimation of the absorbed dose in radiosensitive organs, located away from the target volume during radiotherapy, is one of the main reasons for the development of reference phantoms. The International Commission on Radiological Protection (ICRP) reference phantoms can provide a more realistic view of the human anatomy in comparison with the previously used mathematical p...
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