Understanding radiation therapy
How it works and what a typical course looks like
The short version
Radiation therapy uses high-energy beams to damage cancer cells in a specific area. It's usually given in short daily sessions over several weeks, starting with a planning appointment called a simulation.
Radiation therapy directs high-energy beams at a specific area to damage cancer cells and slow or stop their growth. For breast cancer, it's often given after surgery to reduce the chance of the cancer returning in that area.
The simulation appointment
Before treatment starts, most people have a planning session called a simulation, where the team maps out exactly where the radiation needs to go and may make small, permanent marks on the skin to line things up precisely for each session.
What sessions are usually like
Individual treatment sessions are often quick — the appointment may take 15–30 minutes, but the radiation itself typically lasts only a few minutes. Most courses run five days a week for several weeks, though this varies by treatment plan.
Questions you may want to ask
How many sessions are planned, and how long is each one?
What skin care routine do you recommend during treatment?
What fatigue or other side effects are common with this plan?