This study investigated radiation dose variations in pre-clinical irradiation due to the photon beam energy and presence of tissue heterogeneity. Based on the same mouse computed tomography image dataset, three phantoms namely, heterogeneous, homogeneous and bone homogeneous were used. These phantoms were generated by overriding the relative electron density of no voxel (heterogeneous), all vox...

Current dosimetry protocols (AAPM, IAEA, DIN) recommend the use of parallel-plate ionization chambers for the measurement of absorbed dose-to-water in clinical electron beams. For well-guarded plane-parallel chambers, it is assumed that the perturbation correction pQ is unity for all electron energies. In this study, we present detailed Monte Carlo simulations with the EGSnrc code for the widel...

PURPOSE Total Skin Electron Irradiation (TSEI) is a complex technique which usually involves the use of large electron fields and the dual-field approach. In this situation, many electrons scattered from the treatment room floor are produced. However, no investigations of the effect of scattered electrons in TSEI treatments have been reported. The purpose of this work was to study the contribut...

3D-microCT images of vertebral bodies from three different individuals have been segmented into trabecular bone, bone marrow and bone surface cells (BSC), and then introduced into the spongiosa voxels of the MAX06 and the FAX06 phantoms, in order to calculate the equivalent dose to the red bone marrow (RBM) and the BSC in the marrow cavities of trabecular bone with the EGSnrc Monte Carlo code f...

Introduction: During the last decades, simulation of radiation therapy treatment conditions in treatment room for studying with more details in comparison with treatment planning system (TPS) is taken into consideration. The most problem with starting these kind of researches is the geometry of Medical linacs and verification of the accelerators. Therefore, researchers tried to...

This study evaluated the dosimetric impact of surface dose reduction due to the loss of backscatter from the bone interface in kilovoltage (kV) X-ray radiation therapy. Monte Carlo simulation was carried out using the EGSnrc code. An inhomogeneous phantom containing a thin water layer (0.5-5 mm) on top of a bone (thickness = 1 cm) was irradiated by a clinical 105 kVp photon beam produced by a G...

Relative absorbed-dose energy response correction R for different detector materials in water, PMMA and polystyrene phantoms are calculated using Monte Carlo-based EGSnrc code system for ¹²⁵I and ¹⁶⁹Yb brachytherapy sources. The values of R obtained for ¹²⁵I source are 1.41, 0.92, 3.97, 0.47, 8.32 and 1.10, respectively, for detector materials LiF, Li₂B₄O₇ , A1₂O₃, diamond, silicon diode and ai...

Ongoing controversy surrounds the adverse health effects of the use of depleted uranium (DU) munitions. The biological effects of gamma-radiation arise from the direct or indirect interaction between secondary electrons and the DNA of living cells. The probability of the absorption of X-rays and gamma-rays with energies below about 200 keV by particles of high atomic number is proportional to t...

A prototype of a new dose-verification system has been developed to facilitate prevention and identification of dose delivery errors in remotely afterloaded brachytherapy. The system allows for automatic online in vivo dosimetry directly in the tumor region using small passive detector probes that fit into applicators such as standard needles or catheters. The system measures the absorbed dose ...

Iodine-125 ((125)I) and Caesium-131 ((131)Cs) brachytherapy have been used with sublobar resection to treat stage I non-small cell lung cancer and other radionuclides, (169)Yb and (103)Pd, are considered for these treatments. This work investigates the dosimetry of permanent implant lung brachytherapy for a range of source energies and various implant sites in the lung. Monte Carlo calculated d...