Background: As the volumetric modulated arc therapy (VMAT) becoming a main role of treatment ways, the effect of couch top becomes more significant. It is imperative to re-evaluate the couches that previously may have been considered of no importance during early treatment techniques. The impact of couch top on radiation delivery was explored and the couch model was tested with the aim of reduc...

Purpose Conical collimators, or cones, are tertiary collimators that attach to a radiotherapy linac and suited for the stereotactic radiosurgery treatment of small brain lesions. The diameter most used cones makes difficult acquisition dosimetry data needed commissioning planning systems. Although many publications report dosimetric conical radiosurgery, works use different setups, which compli...

Introduction: Accurate film dosimetry requires careful consideration of sources of uncertainty. Some of the sources of uncertainty are dependent on the size and location of region of interest (ROI), especially in small fields. Avoiding the penumbra is often a reason for using a small ROI. In contrast, choosing very small ROIs may increase uncertainty due to the reduction of th...

Background: Total body irradiation (TBI) is a technique that is commonly used as a part of the patient conditioning regimen before the bone marrow transplant (BMT). The purpose of this study is to introduce and implement a reasonable TBI technique on the human-like phantom in Imam Khomeini Hospital in Tehran. Methods: The present experimental study was conducted from October 2016 to November 2...

Purpose: To investigate the energy dependence/spectral sensitivity of silicon diodes designed for small-field dosimetry and obtain response factors (RFs) for arbitrary photon spectra using Monte Carlo (MC) simulations.   Methods: The EGSnrc user-code DOSRZnrc was used to calculate the dose deposition in water and in the active volume of a stereotactic diode f...

Introduction: The Purpose of this study has been measuring midline dose for the patients undergoing brain radiotherapy without any need to build-up cap. Materials and Methods: The study was performed on 28 patients with brain tumor undergoing 15 MV radiotherapy by a Siemens LINAC. To estimate the midline dose, the entrance and exit doses were calculated b...

  Introduction:    Multileaf collimators (MLCs) are computer-controlled devices which are Useful and cost-effective tools for conformal therapy and intensity modulation radiotherapy (IMRT). Nowadays MLCs are important and standard configuration of the new medical linear accelerators which are substitute of conventional Blocks and has eliminated the ...

This study details the generation, verification, and implementation of a treatment planning system (TPS) couch top model for patient support system used in conjunction with a dedicated stereotactic linear accelerator. Couch top model was created within the TPS using CT simulation images of the kVue Calpyso-compatible couchtop (with rails). Verification measurements were compared to TPS dose pre...

BACKGROUND The EORTC has launched a phase II trial to assess safety and efficacy of SBRT for centrally located NSCLC: The EORTC 22113-08113-Lungtech trial. Due to neighbouring critical structures, these tumours remain challenging to treat. To guarantee accordance to protocol and treatment safety, an RTQA procedure has been implemented within the frame of the EORTC RTQA levels. These levels are ...

The purpose of this work was to experimentally investigate the out-of-field dose in a water phantom, with several high energy electron beams used in external beam radiotherapy (RT). The study was carried out for 6, 9, 12, and 18 MeV electron beams, on three different linear accelerators, each equipped with a specific applicator. Measurements were performed in a water phantom, at different depth...