Basic Radiotherapy Physics And Biology -

Radiotherapy primarily uses high-energy , such as X-rays, gamma rays, protons, and electrons. Unlike visible light, this radiation carries enough energy to knock electrons out of atoms, a process called ionization .

: At the energies used in treatment, photons (X-rays) typically interact via Compton scattering , where they bounce off electrons and transfer energy to them. Direct vs. Indirect Ionization : Direct : The radiation beam itself breaks DNA strands. Basic Radiotherapy Physics and Biology

Not all radiation is created equal. The describes how much energy a particle deposits as it travels through tissue: Radiotherapy primarily uses high-energy , such as X-rays,

: Modern techniques like IMRT (Intensity Modulated Radiotherapy) and Proton Therapy allow physicists to conform the dose strictly to the tumor, sparing nearby healthy organs like the salivary glands or the liver. 2. The Biology: The "5 R’s" of Radiotherapy Direct vs

For those looking to master these concepts, the textbook Basic Radiotherapy Physics and Biology by and colleagues is a widely used resource for residents and medical professionals. It provides a concise review of these topics, including the linear-quadratic (LQ) model used to predict cell survival. David Chang, MD - Ochsner Health

: Different tissues have inherent differences in how they respond to radiation. For example, lymphocytes and bone marrow are highly sensitive, while muscle and nerve tissues are more resistant. 3. High-LET vs. Low-LET Radiation

: These deposit energy sparsely. Most of their damage is indirect and easily repairable by healthy cells.