Radiotherapy is one of the most common and effective treatments for cancer. Many patients ask:
Here is a simple explanation — no medical jargon — so you can understand exactly how radiotherapy works.
1. Radiotherapy uses high-energy beams to kill cancer cells
A machine called a LINAC (linear accelerator) sends precise beams of energy to a tumor.
These beams damage the DNA of cancer cells so they:
- stop multiplying
- shrink
- eventually die
Healthy cells can repair themselves — cancer cells cannot. This is why radiotherapy works.
2. The radiation does NOT make your body radioactive
Many patients worry they might emit radiation after treatment.
3. Treatment is planned very carefully before it begins
Before radiotherapy starts, you undergo a planning process:
a. CT-simulation
A special CT scan is done to map the exact area that needs treatment.
b. Contouring
Your radiation oncologist outlines:
- the tumor
- nearby organs
- important structures to protect
c. Treatment planning
A medical physicist creates a customized 3D plan to target your tumor precisely while protecting healthy tissue.
d. Machine calibration & safety checks
Every plan goes through safety tests before your first session.
4. During treatment, the machine rotates around you — but never touches you
You lie on the table, and the LINAC moves around you to deliver beams from different angles.
- You must stay still for a few minutes.
- You do NOT feel the radiation.
- You may hear machine sounds — this is normal.
5. Radiotherapy works slowly and safely over time
Most treatments are given daily (Monday–Friday) over several weeks.
Why not give all the radiation in one day?
6. What radiotherapy does NOT do
- It does NOT burn your skin from the inside
- It does NOT cause electric shock
- It does NOT melt or cook organs
- It does NOT stay in your body
7. Why different patients receive different doses
The amount of radiation depends on:
- cancer type
- tumor size
- treatment goal (curative vs palliative)
- nearby organs
Your doctor chooses the safest and most effective dose for your situation.
8. Side effects come from normal tissue healing — not from radiation “inside” the body
Fatigue, skin darkening, or mild soreness happen because healthy cells are recovering from treatment.
9. When radiotherapy is commonly used
- breast cancer
- head & neck cancer
- cervical cancer
- lung cancer
- prostate cancer
- brain tumors
- painful bone metastases
- bleeding tumors
10. Key message
Have more questions?
You can message us anytime for general guidance.
This article is for educational purposes only and does not replace medical consultation.