Uncertainty Analysis in MRI-based Polymer Gel Dosimetry
Journal Title: Journal of Biomedical Physics and Engineering - Year 2017, Vol 7, Issue 3
Abstract
Background: Polymer gel dosimeters combined with magnetic resonance imaging (MRI) can be used for dose verification of advanced radiation therapy techniques. However, the uncertainty of dose map measured by gel dosimeter should be known. The purpose of this study is to investigate the uncertainty related to calibration curve and MRI protocol for MAGIC (Methacrylic and Ascorbic acid in Gelatin Initiated by Copper) gel and finally ways of optimization MRI protocol. Materials and Methods: MAGIC gel was prepared by the Fong et al. instruction. The gels were poured into calibration vials and irradiated by 18 MV photons. 1.5 Tesla MRI was used for reading out information. Finally, uncertainty of measured dose was calculated. Results: Results show that for MAGIC polymer gel dosimeter, at low doses, the estimated uncertainty is high (≈ 18.96% for 1 Gy) but it reduces to approximately 4.17% for 10 Gy. Also, with increasing dose, the uncertainty for the measured dose decreases non-linearly. For low doses, the most significant uncertainties are σ_R0 (uncertainty of intercept) and σ_a (uncertainty of slope) for high doses. MRI protocol parameters influence signal-to-noise ratio (SNR). Conclusion: The most important source of uncertainty is uncertainty of R2. Hence, MRI protocol and parameters therein should be optimized. At low doses, the estimated uncertainty is high and reduces by increasing dose. It is suggested that in relative dosimetry, gels are irradiated by high doses in linear range of given gel dosimeter and then scaled down to the desired dose range.
Authors and Affiliations
M Keshtkar, A Takavar, M H Zahmatkesh, A R Montazerabadi
Keywords
Related Articles
- EP ID EP331811
- DOI -
- Views 102
- Downloads 0
Craniospinal Irradiation in Medulloblastoma using High Energy Medical Linear Accelerator: an Innovative Approach to Planning Technique
Background: Craniospinal irradiation (CSI) of medulloblastoma poses technological challenges due to the involvement of large treatment volume. Commonly, the whole treatment length is covered with two different isocentric...
Effect of Exposure to 900 MHz GSM Mobile Phone Radiofrequency Radiation on Estrogen Receptor Methylation Status in Colon Cells of Male Sprague Dawley Rats
Background: Over the past several years, the rapidly increasing use of mobile phones has raised global concerns about the biological effects of exposure to radiofrequency (RF) radiation. Numerous studies have shown that...
In-silico Evaluation of Rare Codons and their Positions in the Structure of ATP8b1 Gene
Background: Progressive familial intrahepatic cholestases (PFIC) are a spectrum of autosomal progressive liver diseases developing to end-stage liver disease. ATP8B1 deficiency caused by mutations in ATP8B1 gene encoding...
Trunk Kinematic Analysis during Gait in Cerebral Palsy Children with Crouch Gait Pattern
Background: Deficits in upper body movement have received little attention during gait in cerebral palsy (CP) children with crouch gait pattern (CGP). Objective: Purpose of this research is to describe the correlation of...
Enhancement of Toxic Substances Clearance from Blood Equvalent Solution and Human Whole Blood through High Flux Dialyzer by 1 MHz Ultrasound
Background Hemodialysis is a process of removing waste and excess fluid from blood when kidneys cannot function efficiently. It often involves diverting blood to the filter of the dialysis machin to be cleared of toxic s...