Simulation of ITV and GTV doses in SBRT treatment of lung cancer

Background: Stereo-tactic body radiation therapy (SBRT) has emerged as a highly effective treatment for early-stage non-small cell lung cancer (NSCLC) and metastatic lung tumors. Its ability to deliver high doses of radiation precisely to the tumor while sparing surrounding healthy tissue makes it a preferred option for inoperable cases. Accurate dose distribution assessment is critical for optimizing treatment plans and minimizing toxicity risks. Objective: This study aims to analyze the dose distribution of SBRT in lung cancer treatment using Monte Carlo simulations and experimental verification. By evaluating dose accuracy and its impact on surrounding tissues, the study seeks to improve treatment precision and patient safety. Methods: We employed Monte Carlo-based simulations to model radiation dose distributions for lung tumors treated with SBRT. The simulated dose distributions were compared with experimental measurements using ionization chambers and film dosimetry in a lung-equivalent phantom. Key parameters, including dose heterogeneity, tumor coverage, and organ-at-risk (OAR) exposure, were analyzed to validate the treatment planning system (TPS). Results: Preliminary findings indicate that Monte Carlo simulations provide higher accuracy in predicting lung dose distributions compared to conventional algorithms. Differences in calculated vs. measured doses highlight the need for improved heterogeneity corrections in TPS. Conclusion: Monte Carlo simulations offer a reliable approach for evaluating SBRT dose distributions in lung cancer patients. Their integration into clinical workflows could enhance treatment planning accuracy, ultimately improving therapeutic outcomes while minimizing toxicity risks.