Shahrokh Nasseri
Medical Physics Research Center, Medical Physics Department, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
[ 1 ] - Calculations of Linac Photon Dose Distributions in Homogeneous Phantom Using Spline
Introduction Relative dose computation is a necessary step in radiation treatment planning. Therefore, finding an approach that is both fast and accurate seems to be necessary. The purpose of this work was to investigate the feasibility of natural cubic spline to reconstruct dose maps for linear accelerator radiation treatment fields in comparison with those of the simulation. Materials and Met...
[ 2 ] - Evaluation of the Portal Imaging System Performance for an Elekta Precise Linac in Radiotherapy
Introduction: Electronic portal imaging devices (EPIDs) provide two- and three-dimensional planar and volumetric cone beam images to improve the accuracy of radiation treatment delivery. Periodic quality assurance (QA) of EPIDs is essential for dosimetric verification in radiotherapy. In this study, a QA program was implemented to evaluate the function of the EPID to be confident in applying co...
[ 3 ] - تأثیر کاهش اثر ساختگی فلز در برآورد توزیع دوز توسط نرم افزار طراحی درمان ISOgray
هدف: در بدن برخی از بیماران مبتلا به سرطان و تحت درمان با اشعه، اجسام خارجی فلزی وجود دارند که عدد اتمی آن ها تفاوت زیادی با عدد اتمی بافت های بدن دارد. این امر موجب ایجاد آرتیفکت در تصاویر، اختلاف زیاد در اعداد سی تی و خطا در محاسبات می شود. این مطالعه جهت بررسی تاثیر اصلاح آرتیفکت فلز بر تصاویر و مقایسه میزان دوز محاسباتی توسط سیستم طراحی درمان ISOgray با دوز اندازه گیری شده انجام گرفته ا...
[ 4 ] - Mega Voltage Cone Beam Computed Tomography (MV- CBCT) using a Standard Medical Linear Accelerator and EPID: A feasibility study.
Introduction: The success of radiotherapy cancer treatment delivery depends on the accuracy of patient positioning for each treatment session. A number of kilovoltage x-ray volumetric imaging modalities with an additional source and detector have been developed to allow patient set-up verification based on the internal anatomy, but a significant portion of medical linacs are on...
[ 5 ] - Sex-related Left Ventricle Rotational and Torsional Mechanics by Block Matching Algorithm
Background: The aim of the present study was to evaluate how left ventricular twist and torsion are associated with sex between sex groups of the same age.Materials and Methods: In this analytical study, twenty one healthy subjects were scanned in left ventricle basal and apical short axis views to run the block matching algorithm; instantaneous changes in the base and apex rotation angel...
[ 6 ] - Evaluation of Breast Cancer Radiation Therapy Techniques in Outfield Organs of Rando Phantom with Thermoluminescence Dosimeter
Background: Given the importance of scattered and low doses in secondary cancer caused by radiation treatment, the point dose of critical organs, which were not subjected to radiation treatment in breast cancer radiotherapy, was measured.Objective: The purpose of this study is to evaluate the peripheral dose in two techniques of breast cancer radiotherapy with two energies. Methods: Eight diff...
[ 7 ] - Utilization of Electronic Portal Imaging Device (EPID) For Setup Verification and Determination of Setup Margin in Head and Neck Radiation Therapy
Introduction: Radiation therapy involves a multistep procedure; therefore, the error in patient set up is an inherent part of the treatment. Main purpose of this study was to determine the clinical target volume (CTV) to planning target volume (PTV) in head and neck cancer patients. Material and Methods: A total of 15 patients who had daily p...
[ 8 ] - Contribution of 68Ga-PSMA PET/CT to targeting volume delineation of prostate cancer treated with conformal radiation therapy: Which SUV threshold is appropriate?
Introduction: Prostate-specific membrane antigen (PSMA) has been demonstrated as a promising tool for specific imaging of prostate cancer (PCa) via positron emission tomography-computed tomography (PET/CT) scanning. Radiation treatment planning (RTP) based on 68Ga-PSMA PET/CT scanning can also lead to some decision modifications. The specific goal o...
[ 9 ] - Geometric distortion evaluation of magnetic resonance images by a new large field of view phantom for magnetic resonance based radiotherapy purposes
Background: The magnetic resonance imaging (MRI)-based radiotherapy planning method have been considered in recent years because of the advantages of MRI and the problems of planning with two images modality. The first step in MRI-based radiotherapy is to evaluate magnetic resonance (MR) images geometric distortion. Therefore, the present study aimed to evaluate system related geometric distort...
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