Author: Ana Laura Burin, Ilca Marli Moitinho Amaral Medeiros, Priscila Santos Rodrigues, Maria Elisa Chuery Martins Rostelato, Sabrina Spigaroli Sgrignoli, Ana Catarina Koka de Souza Silva, Carla Daruich Souza, Cristhian Ferreira Talacimon, Lara El Hajj Teodoro, Carlos Alberto Zeituni 👨🔬
Affiliation: IPEN - USP, IPEN - Instituto de Pesquisas Energéticas e Nucleares 🌍
Purpose: The uniform distribution of phosphorus-32 (32P) in beta sources is essential to ensure the accuracy of radiotherapy treatments, such as those for paravertebral cancer. This study evaluated the homogeneity of a polymeric source containing 32P, using computational tools and Monte Carlo simulations (MCNP6.2). The objective was to identify variations that could compromise precise dose delivery to the target tissue, aiming to improve quality control in the manufacturing of these sources
Methods: Based on simulated data, a matrix representing the distribution of 32P was created. A Python algorithm was developed to compute uniformity statistics, including mean, standard deviation, coefficient of variation, and regional percentage differences. Heatmaps were generated to visualize the distribution and identify irregularities. MCNP6.2 simulations were conducted to correlate the radionuclide distribution with absorbed dose in a homogeneous phantom, considering geometries typical of clinical applications.
Results: The results showed significant variations in the 32P distribution, with a coefficient of variation of 8.5% and percentage differences reaching up to 20% relative to the mean. These variations indicate areas with higher 32P concentrations, which could impact the dose absorbed by the simulated tissues. However, the analysis demonstrated that these differences can be identified and corrected, contributing to the improvement of uniformity in source production, which is crucial for treatment accuracy.
Conclusion: The developed algorithm proved effective in evaluating the uniformity of beta sources. Its integration with Monte Carlo simulations highlights the importance of a homogeneous distribution to ensure safety and efficacy in treatments. This method contributes to the optimization of the manufacturing process and the development of more reliable sources for medical applications.