Introduction: In radiation therapy, knowing the dose rates to healthy organs and tumors is beneficial, and thermoluminescent dosimeter (TLD) allows for this possibility. This study was aimed at determining the dose-response differences of TLDs in various types of radiation, energy levels, and dose rate calibrated with other types of radiation beams and energy and dose levels. Materials and Meth...

BACKGROUND The purpose of this study is to find the optimal planning settings for prostate SABR-VMAT for high-risk prostate cancer patients irradiated to prostate only (PO) or prostate and pelvic lymph nodes (PPLN). METHODS For 10 patients, plans using 6MV flattened, flattening-filter-free (FFF) 6MV (6 F) and FFF 10MV (10 F) photon beams with full and partial arc arrangements were generated a...

ntroduction:  monte  carlo  simulation  is  the  most  accurate  method  of  simulating  radiation  transport  and  predicting doses at different points of interest in radiotherapy. a great advantage of the monte carlo method  compared  to  the  deterministic  methods  is  the  ability  to  deal  accurately  with  any  complex  geometry.  its  disadvantage is the extremely long computing time r...

Background: The presence of a wedge filter in the beam trajectory can modify the beam quality and cause some changes in the dosimetry parameters which are usually difficult to be measured directly and accurately. Material and Methods: In this study the MCNP-4C Monte Carlo code was used to simulate the 9 MV photon beam generated by a linear accelerator. Upon getting a good agreement bet...

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...

BACKGROUND Tumor immune-evasion and associated failure of immunotherapy can potentially be overcome by radiotherapy, which however also has detrimental effects on tumor-infiltrating and circulating lymphocytes (CL). We therefore established a model to simulate the radiation-dose delivered to CL. METHODS A MATLAB-model was established to quantify the CL-dose during SBRT of liver metastases by ...

The use of Monte Carlo methods in photon beam treatment planning is becoming feasible due to advances in hardware and algorithms. However, a major challenge is the modeling of the radiation produced by individual linear accelerators. Monte Carlo simulation through the accelerator head or a parameterized source model may be used for this purpose. In this work, the latter approach was chosen due ...

As regards, the selection of appropriate energy in radiotherapy tumors that are placed in non-homogen areas is important, so the aim of the present study is evaluating the effect of 6 and 15MV photon beam energies on dose distribution in 3D-CRT for lower esophageal and rectal cancers. 12 patients with lower esophageal cancer and 12 patients with rectal cancer respectively, with the prescription...

Purpose Monte Carlo (MC) models of radiotherapy beams can be used as a comparison benchmark for other dose calculation methods. In any such comparison process, the degree to which an identified deviation represents an actual error will depend upon the accuracy of the benchmark. As part of an ongoing dosimetric study, we have sought to model the standard Varian Clinac 6MV beam as accurately as p...