Effects of Tissue Heterogeneities on Dose Estimation in Brachytherapy.

Abstract

This study investigated the impact of tissue heterogeneities on dose estimation during brachytherapy treatments. Variations in tissue densities can significantly influence dose distribution, potentially affecting treatment efficacy and patient outcomes. The research was conducted at the National Radiotherapy Oncology and Nuclear Medicine Centre (NRONMC) at Korle Bu Teaching Hospital, Accra, Ghana. A Perspex phantom was fabricated to replicate the human body, and materials such as NaOH, Frytol vegetable oil, Quartz Total (SAE15W-40) engine oil, and air were used to simulate various human tissues, including liver, muscle, adipose, and lungs (exhaled). The results revealed discrepancies between the dose calculated by the treatment planning system (TPS) and the measured dose, suggesting that the actual dose received by the tumor can be influenced by tissue heterogeneities. The percentage dose differences, which ranges from -34% to 2.10% in summary, highlighted the significant role of tissue density and positioning in shaping dose distribution during brachytherapy. While the study demonstrates the importance of accounting for tissue heterogeneities, the limited range of materials used to mimic human tissues represents a limitation, suggesting the need for further research with a broader variety of tissue-equivalent materials. These findings emphasize the necessity of incorporating tissue density variations into dose calculations for more accurate brachytherapy treatment planning.