Mahmoud Allahverdi
Department of Medical Physics, Tehran University of Medical Sciences, Tehran, Iran
[ 1 ] - Experimental Evaluation of Depth Dose by Exit Surface Diode Dosimeters for Off-Axis Wedged Fields in Radiation Therapy
Introduction Evaluation of the delivered dose of externally wedged photon beams by external diode dosimeters during the treatment process requires the estimation of exit surface dose correction factors in various wedge angles and field sizes. Materials and Methods A system of absorbed dose evaluation, using p-type diode dosimeters placed on the exit surface of a phantom, was characterized for e...
[ 2 ] - Optimization of 3D Planning Dosimetry in a Breast Phantom for the Match Region of Supraclavicular and Tangential Fields
Introduction: The complex geometry of breast and also lung and heart inhomogeneities near the planning target volume (PTV) result in perturbations in dose distribution. This problem can result in overdosage or underdosage in the match region of the three treatment fields. The purpose of this study is to create a homogeneous dose distribution in the match region between the supraclavicular and t...
[ 3 ] - Evaluation of the RtDosePlan Treatment Planning System using Radiochromic Film and Monte Carlo Simulation
Introduction: GafChromic EBT films are one of the self-developing and modern films commercially available for dosimetric verification of treatment planning systems (TPSs). Their high spatial resolution, low energy dependence and near-tissue equivalence make them suitable for verification of dose distributions in radiation therapy. This study was designed to evaluate the dosimetric parameters of...
[ 4 ] - Verification of the Accuracy of the Delivered Dose in Pelvic and Breast Cancer Radiotherapy by in-vivo Semi-Conductor Dosimetry
Introduction: Delivering maximum dose to tumor and minimum dose to normal tissues is the most important goal in radiotherapy. According to ICRU, the maximum acceptable uncertainty in the delivered dose compared to the prescribed dose should be lower than 5%, and this is because of the relationship between absorbed dose, tumor control and normal tissue damage. Absorbed dose accuracy is investiga...
[ 5 ] - Evaluation of MRI-based Polymer Gel Dosimetry for Measurement of CT Dose Index (CTDI) on 64 slices CT Scanners
Introduction: Computed tomography (CT) has numerous applications in clinical procedures but its main problem is its high radiation dose to the patients compared to other imaging modalities using x-ray. CT delivers approximately high doses to the nearby tissues due to the scattering effect, fan beam (beam divergence) and limited collimator efficiency. The radiation dose from multi-slice scanners...
[ 6 ] - Diode calibration for dose determination in total body irradiation
Background: Total Body Irradiation (TBI) is different from standard radiotherapy in many aspects, so it is not easy to predict the delivered dose to the patient under TBI treatment. Diode dosimetry procedures for surface dose reading can help to define variations of the actually delivered dose from the prescribed one. The aim of this study was to describe the measurements made to calib...