Basic Radiotherapy Physics And Biology Apr 2026

Not all radiation is created equal. The describes how much energy a particle deposits as it travels through tissue:

: Normal cells are often better at repairing sublethal DNA damage than cancer cells. Basic Radiotherapy Physics and Biology

: Oxygenated cells are about three times more sensitive to radiation than hypoxic (oxygen-poor) ones. As a tumor shrinks, previously hidden hypoxic areas get better blood flow and become easier to kill. Not all radiation is created equal

Radiotherapy is a cornerstone of modern cancer treatment, utilized by approximately 50% of all cancer patients. But how does a beam of energy actually "cure" a disease? The answer lies at the intersection of —the science of how energy interacts with matter—and radiation biology —the study of how living cells respond to that energy. 1. The Physics: Interaction of Radiation with Matter As a tumor shrinks, previously hidden hypoxic areas

: The radiation hits water molecules in the cell, creating reactive oxygen species (free radicals) that then attack the DNA.