Abolfazl Kanani, Amir Owrangi, Mehran Yazdi, Ali Fatemi-Ardekani, Mohammad Amin Mosleh-Shirazi
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引用次数: 0
Abstract
Purpose: Suitable commissioning and quality control (QC) tests for high-dose-rate brachytherapy (HDR-BT) is necessary to ensure dosimetric and geometric accuracy of the treatment. This study aimed to present the methodology of developing a novel multi-purpose QC phantom (AQuA-BT) and examples of its' application in 3D image-based (particularly magnetic resonance imaging [MRI]-based) planning for cervix BT.
Material and methods: Design criteria led to a phantom with sufficient size waterproof box for dosimetry and capability for inserting other components inside the phantom for: (A) Validating dose calculation algorithms in treatment planning systems (TPSs) using a small-volume ionization chamber; (B) Testing volume calculation accuracy in TPSs for bladder, rectum, and sigmoid organs at risk (OARs) constructed by 3D printing; (C) Quantification of MRI distortions using 17 semi-elliptical plates with 4,317 control points to mimic a realistic female's pelvis size; and (D) Quantification of image distortions and artifacts induced by MRI-compatible applicators using a specific radial fiducial marker. The utility of the phantom was tested in various QC procedures.
Results: The phantom was successfully implemented for examples of intended QC procedures. The maximum deviation between the absorbed doses to water assessed with our phantom and those calculated by SagiPlan TPS was 1.7%. The mean discrepancy in volumes of TPS-calculated OARs was 1.1%. The differences between known distances within the phantom on MR imaging were within 0.7 mm compared with computed tomography.
Conclusions: This phantom is a promising useful tool for dosimetric and geometric quality assurance (QA) in MRI-based cervix BT.
期刊介绍:
The “Journal of Contemporary Brachytherapy” is an international and multidisciplinary journal that will publish papers of original research as well as reviews of articles. Main subjects of the journal include: clinical brachytherapy, combined modality treatment, advances in radiobiology, hyperthermia and tumour biology, as well as physical aspects relevant to brachytherapy, particularly in the field of imaging, dosimetry and radiation therapy planning. Original contributions will include experimental studies of combined modality treatment, tumor sensitization and normal tissue protection, molecular radiation biology, and clinical investigations of cancer treatment in brachytherapy. Another field of interest will be the educational part of the journal.