The objective of the article was to assess therapeutic linear accelerator performance. Material & method used were quality control tools, direct measurement & theoretical calculation methods. The analysis of results showed that: shift of machine isocenter was 1 mm then increases up to 2 mm through the gantry angles 0 to 300° and 300 to 360 respectively. The diaphragm rotation isocenter clock & ...

We hypothesize that the correlation between the radiation dose expressed as the biologically effective dose (BED) and the clinical endpoints will correlate better as the value of the α/β ratio is increased to >10 Gy, which theoretically minimizes the overestimation of the dose potency associated with the linear quadratic (LQ) formula in the setting of stereotactic body radiation therapy (SBRT) ...

PURPOSE Fiber carbon is the most common material used in treating couch as it causes less beam attenuation than other materials. Beam attenuation replaces build-up region, reduces skin-sparing effect and causes target volume under dosage. In this study, we aimed to evaluate beam attenuation and variation of build-up region in 550 TxT radiotherapy couch. MATERIALS AND METHODS In this study, we...

BACKGROUND Fiducial markers and daily electronic portal imaging (EPI) can reduce the risk of geographic miss in prostate cancer radiotherapy. The purpose of this study was to estimate CTV to PTV margin requirements, without and with the use of this image guidance strategy. METHODS 46 patients underwent placement of 3 radio-opaque fiducial markers prior to prostate RT. Daily pre-treatment EPIs...

The study of cell survival following exposure to nonuniform radiation fields is taking on particular interest because of the increasing evidence of a nonlinear relationship at low doses. We conducted in vitro experiments using the MCF7 breast cancer cell line. A 2.4 × 2.4 cm(2) square area of a T25 flask was irradiated by a Varian Novalis accelerator delivering 6 MV photons. Cell survival insid...

Introduction: Dose distribution can be affected by diverse parameters, such as beam orientations, and collimator angles. These parameters should respect and maintain the international recommended levels during the realization of the quality assurance protocols of linear accelerators. This study aimed at evaluating the dosimetric effects on treatment quality considering...

introduction: gamma knife is an instrument specially designed for treating brain disorders. in gamma knife, there are 201 narrow beams of cobalt-60 sources that intersect at an isocenter point to treat brain tumors. the tumor is placed at the isocenter and is treated by the emitted gamma rays. therefore, there is a high dose at this point and a low dose is delivered to the normal tissue surroun...

PURPOSE To develop a new IMRT technique to simplify the process and improve efficiency in radiotherapy treatment planning for craniospinal irradiation (CSI) treatment. METHODS Image data of 9 patients who received CSI treatment in 2012 were used, the prescription was 36Gy in 20 fractions. Two treatment plans were created for each patient, one was with the new technique called three-isocenter ...