Determinação do perfil da radiação espalhada em mamografia digital utilizando simulações Monte Carlo

Abstract

Mammography is the imaging technique recommended for screening and early diagnosis of breast cancer. In the process of image formation, part of the radiation used is scattered and reaches the receptor, degrading the quality and resolution of the final image, compromising diagnosis. Understanding the profile of scattered radiation distribution is essential for the development and enhancement of post-processing techniques used in mammography image correction. In this study, Monte Carlo simulations were used to map the scatter distribution profile on digital mammography receptors, for breasts with thicknesses ranging from 2 to 8 cm, compositions of 50% glandular and 50% adipose tissue (50-50), 20-80, and 0-100, considering tube potentials ranging from 24 to 32 kV. Based on the simulation results, it was possible to calculate parameters such as the scatter-to-primary ratio (SPR) and mean radial extent (k), which characterize the scattered radiation. The parameters obtained indicate that thicker breasts lead to greater deposi tion of scattered radiation on the receptor, and they exhibit broader scatter profiles and slower decay compared to thinner breasts. SPR and k values showed an increasing be havior with breast thickness, suggesting that among the analyzed factors, thickness most significantly influences changes in scatter radiation distribution, such that thicker breasts are subjected to greater deleterious effects of scatter. These findings can be used in the development of image processing filters aimed at enhancing the accuracy of diagnoses through mammography.