3 Boyutlu Baskı Teknolojisi Kullanılarak Hastaya Özgün Konturlarla Oluşturulan Fantom Tasarımı ve Üretimi ile Mikro-Çok Yapraklı Kolimatör Tabanlı Beyin ve Başboyun Yoğunluk Ayarlı Radyoterapi Planlarının Kalite Kontrolü

Abstract

SUNEL, S. Quality control of micro-multileaf collimator based brain and head-and-neck intensity modulated radiotherapy plans with patient-specific phantom design and production using 3D printing technology. Hacettepe University Institute of Health Sciences, MSc. Thesis in Radiotherapy Physics Program, Ankara, 2017. Patient-specific quality assurance is necessary to enhance the treatment accuracy in radiotherapy facilities In this study, it is aimed to propose an alternative method to standard QA procedures by producing tissue-equivalent phantoms in the form of patient surface using 3D printing technology and thus, with time, this methods will be commonly preferred for patient-specific QA in radiotherapy clinics. The outlines of the methodology of the study designed with the aims can be summarized as: (i) Transferring the CT images of selected Head&Neck patients to workstation, (ii) Transporting the CT images to 3D Slicer software and then preparing the model with the form of patient surface in computer environment, (iii) Transporting the parts of models to 3D printer and printing the crusts of the phantom, (iv) Filling the crusts with paraffin wax, (v) Taking the CT images of model and calculating the doses in the treatment planning system (TPS), (vi) Delivering the micro-MLC based IMRT treatment plans in Novalis unit by placing the EBT3 films between the phantom slices, (vii) performing the gama analysis of 2D dose distributions acquired from EBT3 film and TPS. In the gama analyses of treatment plannings of six head&neck patients, the four sets of criteria were used: 3% dose difference (DD) & 3 mm Distance to Agreement (DTA), 3% DD & 5 mm DTA, 5% DD & 3 mm DTA, and 5% DD & 5 mm DTA. In the analysis with 3mm/3% criteria, it is observed that the dose distributions were agreed except for the dose reduction at the edge of the films induced from the deformation. When 5mm/5% criteria were chosen, the agreements between dose distributions of EBT3 film and TPS were found to be 95,7% in average (max. 96,4% and min. 93,4%). The threshold for success was accepted as 90%. Consequently, our study showed that the head&neck phantoms produced with 3D printing technology can be used for patient specific QA. By means of new technologies that accelerate the production process, 3D phantom applications including surface contour of patients can be routinely used in radiotherapy facilities. Key Words: Patient-Specific IMRT QA, 3D Printing, QA Phantom, PLA, Gafchromic EBT3 film. This thesis study was partially supported by the 3001-116F252 project of that the Scientific and Technological Research Council of Turkey