A new approach to the implementation and operation in Brachytherapy: Comprehensive Analysis for Quality Assurance

Abstract

Relevance: The scientific novelty is 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: The study used gafchromic RTQA2 radiochromic film and a solid polymethylmethacrylate phantom (30x30x1cm3, density 1.05 g/cm³). 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: The experiment results show that the radiochromic film darkens proportionally to the absorbed dose when irradiated, which has the potential to impact the field of brachytherapy significantly. The experimental results demonstrate 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, which efficiently assesses dose distributions around the applicator by combining an Epson Expression 10000XL scanner, a solid phantom with radiochromic film, and ImageJ software, is of significant importance. 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.