A NEW APPROACH TO THE IMPLEMENTATION AND OPERATION IN BRACHYTHERAPY: COMPREHENSIVE ANALYSIS FOR QUALITY ASSURANCE

Abstract

Relevance: The scientific novelty consists in developing a method for estimating dose distributions around the applicator using Gafchromic RTQA2 radiochromic film and a 1 cm thick solid phantom. This technique minimizes deviations between the actual and planned dose distributions around the source. Radiochromic film and solid phantoms allow for detailed analysis of dose profiles, which can optimize source positioning and improve treatment accuracy, especially in the context of 3D planning in high-dose brachytherapy.
The study aimed to improve the accuracy of dosimetric measurements and the quality of procedure planning in brachytherapy.
Methods: Gafchromic RTQA2 radiochromic film and a solid phantom made of polymethylmethacrylate (30×30×1cm3, density 1.05 g/cm³) were used in the study. The doses chosen for analyzing isodose curves around the applicator were 0.6 Gy, 1 Gy, 1.7 Gy, 2 Gy, 2.5 Gy, 3 Gy, and 4 Gy.
Results: According to the experiment, the radiochromic film darkens proportionally to the absorbed dose when irradiated. The experimental results show deviations of the measured data from the planned system in the range of 4.2-10.6%. The lower deviation on the second film indicates a more accurate and stable dose distribution in its region, which can be explained by its optimal location relative to the source and reduced scattering and absorption effects.
Conclusion: The proposed method efficiently assesses dose distributions around the applicator by combining an Epson Expression 10000XL scanner, a solid phantom with radiochromic film, and ImageJ software. The resulting graphs demonstrate how radiation dose correlates with distance through isodose profiles, with RGB channel changes accurately reflecting radiation density. This approach enhances the visualization and validation of dosimetric calculations, making it crucial for improving source positioning and ensuring reliable quality control in brachytherapy through optimized dose modeling.