This study evaluates changes in the dosimetric characteristics of a Varian Millennium 80-leaf multileaf collimator (MLC) in a radiation field. In this study, dose rate, scatter factor, percentage depth dose, surface dose and dose in the buildup region, beam profile, flatness and symmetry, and penumbra width measurements were made for 6-MV and 15-MV photon beams. Analysis of widths between 50% d...

Background:  In this study a series of basic dosimetric properties of a low-density (LD) gel dosimeter are investigated. The dose response is studied regarding to linearity, sensitivity, dose-rate and energy dependence as well as lung tissue equivalence. Materials and Methods: The LD gel was made by mixing the polymer gel with expanded polystyrene spheres. Energy dependence was studied...

Purpose: Acuros XB (AXB) dose calculation algorithm is available for external beam photon dose calculations in Eclipse treatment planning system (TPS). The AXB can report the absorbed dose in two modes: dose-to-water (Dw) and dose-to-medium (Dm). The main purpose of this study was to compare the dosimetric results of the AXB_Dm with that of AXB_Dw on real patient treatment plans. Methods: Four ...

background: in conventional radiation therapy, regarding normal tissue tolerance, the treatment of bulk tumors is one of the remaining challenges. grid radiation therapy (grt) is a technique to deliver high doses, approximately 15 – 20 gy per fraction, to several small volumes located in a large radiation field. this can be performed using a grid block. the current work has concentrated on the ...

Introduction: Concurrent chemoradiotherapy (CRT) is a standard treatment method for patients with carcinoma of cervix. Despite admirable therapeutic results, acute hematologic toxicity (HT) is common with this regimen. Many studies evaluate the relationship between the bone marrow dosimetric parameters and the severity of HT and result shown that the low dose of bone marrow wou...

A combined system comprising the TrueBeam linear accelerator and a new real-time, tumor-tracking radiotherapy system, SyncTraX, was installed in our institution. The goals of this study were to assess the capability of SyncTraX in measuring the position of a fiducial marker using color fluoroscopic images, and to evaluate the dosimetric and geometric accuracy of respiratory-gated radiotherapy u...

background: the aim of this work was to establish how well gel dosimeters performed, as substitutes for brain tissue compared with standard phantom materials such as water, polymethyl-methacrylate (or pmma), a150 plastic and te- liquid phantom material for dosimetry of neutron beams in boron neutron capture therapy. materials and methods: thermal neutron fluence, photon dose and epithermal neut...

Background: The dosimetric performance of Eclipse 6.5 three dimensional treatment planning system (3DTPS) is evaluated by comparing the calculated and measured dose in two dimensions following the guide lines of American Association for Physicists in Medicine Task Group 53. Materials and Methods: The calculations were performed by the 3DTPS for symmetric as well as asymmetric fields for standar...

The International Atomic Energy Agency (IAEA), jointly with the World Health Organization (WHO), has operated a postal dosimetry audit program for radiotherapy centers worldwide since 1969. In 2017 IAEA introduced new methodology based on radiophotoluminescent (RPLD) these audits. detection system consists of phosphate glass dosimeter inserted in plastic capsule that is kept measuring position ...

PURPOSE To present the experience in patient dose management and the development of an online audit tool for digital radiography. MATERIALS AND METHODS Several tools have been developed to extract the information contained in the DICOM header of digital images, collect radiographic parameters, calculate patient entrance doses and other related parameters, and audit image quality. RESULTS Th...