This is Episode 21, Part B: Advanced Modalities - IMRT & FLASH.In our previous episode, we explored the exciting world of particle therapy, looking at how protons and heavy ions like carbon aim to improve treatment by precisely targeting tumors. Today, we continue our journey into advanced radiotherapy modalities, but we’ll shift our focus back to photon-based treatments and a very novel high-dose-rate concept. First, we'll discuss Intensity-Modulated Radiation Therapy, or IMRT, a cornerstone of modern radiotherapy, and examine some of its important radiobiological considerations, particularly regarding integral dose and the risk of secondary cancers. Then, we'll jump to the cutting edge with FLASH radiotherapy, a technique delivering ultra-high dose rates with the tantalizing promise of significantly sparing normal tissues while maintaining tumor control.