Welcome back to Rad Onc Smart Review, the podcast that helps you master the core concepts of radiation oncology and radiobiology. This is Episode 11 part A, Tumor Microenvironment - Hypoxia & Reoxygenation. Today, we're diving deep into the tumor microenvironment, specifically focusing on why some parts of tumors don't get enough oxygen, how this hypoxia affects radiation treatment, and the fascinating reoxygenation process that can occur during fractionated radiotherapy.