Validation of a Computational Model for Light Dosimetry in Lung Therapies: Tailoring Energy-Efficient Monte Carlo Simulations to Thoracic Anatomy and Tissue Optics

External irradiation for photonic therapies in internal organs, such as lungs, faces challenges due to varying patient anatomy. Conditions like pneumonia and COVID-19 demand precise light delivery through the thoracic wall to the lungs. We employed in-house Monte Carlo simulations to model light dosimetry in the lungs. Anatomical 3D models derived from human CT scans included 12 tissue types and lung regions (normal, collapsed infiltrate, blood vessels). Wavelength specific optical properties were based on literature data. Simulations revealed energy deposition and fluence distribution patterns for distinct lung lobes and pathologies (focal/diffuse pneumonia, COVID-19 inflammation) under varied light configurations. This study highlights the need for detailed anatomical and optical modeling to optimize light-based therapies enabling personalized and effective treatment strategies for lung diseases.