Reza Faghihi
Department of Medical Radiation and Radiation Research Center, School of Mechanical Engineering, Shiraz University, Shiraz, Iran
[ 1 ] - Assessment of an Unshielded Electron Field Diode Dosimeter for Beam Scanning in Small- to Medium-Sized 6 MV Photon Fields
Introduction Radiotherapy planning systems require many percentage depth dose (PDD) and profile measurements and there are various dosimeters that can be used to obtain these scans. As dose perturbation is particularly troublesome in smaller photon fields, using a low-perturbation, unshielded electron field diode (EFD) in these fields is of interest. The aim of this work was to investigate the ...
[ 2 ] - Investigation of Anisotropy Caused by Cylinder Applicator on Dose Distribution around Cs-137 Brachytherapy Source using MCNP4C Code
Introduction: Brachytherapy is a type of radiotherapy in which radioactive sources are used in proximity of tumors normally for treatment of malignancies in the head, prostate and cervix. Materials and Methods: The Cs-137 Selectron source is a low-dose-rate (LDR) brachytherapy source used in a remote afterloading system for treatment of different cancers. This system uses active and inactive sp...
[ 3 ] - CT-Based Brachytherapy Treatment Planning using Monte Carlo Simulation Aided by an Interface Software
Introduction: In brachytherapy, radioactive sources are placed close to the tumor, therefore, small changes in their positions can cause large changes in the dose distribution. This emphasizes the need for computerized treatment planning. The usual method for treatment planning of cervix brachytherapy uses conventional radiographs in the Manchester system. Nowadays, because of their advantages ...
[ 4 ] - Investigation of the Effects of Tissue Inhomogeneities on the Dosimetric Parameters of a Cs-137 Brachytherapy Source using the MCNP4C Code
Introduction: Brachytherapy is the use of small encapsulated radioactive sources in close vicinity of tumors. Various methods are used to obtain the dose distribution around brachytherapy sources. TG-43 is a dosimetry protocol proposed by the AAPM for determining dose distributions around brachytherapy sources. The goal of this study is to update this protocol for presence of bone and air inhom...
[ 5 ] - Optimization of Beam Orientation and Weight in Radiotherapy Treatment Planning using a Genetic Algorithm
Introduction: The selection of suitable beam angles and weights in external-beam radiotherapy is at present generally based upon the experience of the planner. Therefore, automated selection of beam angles and weights in forward-planned radiotherapy will be beneficial. Material and Methods: In this work, an efficient method is presented within the MATLAB environment to investigate how to improv...
[ 6 ] - Unfolding X-ray spectrum in the diagnostic range using the Monte Carlo Code MCNP5
Introduction: Unfolding X-ray spectrum is a powerful tool for quality control of X-ray tubes. Generally, the acquisition of the X-ray spectrum in diagnostic radiology departments is complicated and difficult due to high photon flux. Measurement of x ray spectra using radiation detectors could not be performed accurately, because of the pulse pile up. Therefore, indirect methods...
[ 7 ] - Investigation of physical penumbra definition in IMRT applications
Introduction: Because of small size of the beamlets in IMRT, physical penumbra is one of the important dosimetric parameters and small changes in the penumbra will have a great impact on the results. The physical penumbra width is defined as the lateral distance between two specified isodose curves at a specified depth of phantom. In this study, after demonstrating the inconsi...
[ 8 ] - Automated Tumor Segmentation Based on Hidden Markov Classifier using Singular Value Decomposition Feature Extraction in Brain MR images
ntroduction: Diagnosing brain tumor is not always easy for doctors, and existence of an assistant that facilitates the interpretation process is an asset in the clinic. Computer vision techniques are devised to aid the clinic in detecting tumors based on a database of tumor c...
[ 9 ] - Comparison the treatment time of cobalt and iridium sources in HDR brachytherapy
Introduction: The use of long-half-life Cobalt source instead of iridium source will be very helpful in HDR brachytherapy for treatment of cervical cancer. The aim of this study was compared the treatment time with cobalt and iridium source in brachytherapy for treatment of cervical cancer using Tandem-ovoid applicator. Materials and Methods: In this study, 19...
[ 10 ] - Discrepancies in dose distributions due to age- dependent bone electron density in pediatric MRI-only treatment planning: A Monte Carlo study
Introduction: MRI-only treatment planning (TP) can be advantageous in paediatric radiotherapy. However, electron density extraction is necessary for dose calculation. Normally, after bone segmentation, a bulk density is assigned. However, the variation of bone bulk density in patients makes the creation of pseudo CTs challenging. This study aims to assess the effects of bone den...
[ 11 ] - Comprehensive TLD dosimetry of physicians and patients during interventional angiography procedures to estimate the risk of radiation deterministic effect
Introduction: Interventional angiography procedures are increasingly used today. These techniques require a long time of standing near the patient and x-ray tube which lead to increase the radiation-dose of the staff and interventionists. This may also, in turn, lead to the occurrence of radiation deterministic effects. Since a large number of interventional radiology were perf...
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