Radiotherapy uses high-energy “invisible beams” to damage the DNA of cancer cells so they can’t grow or divide. Think of it as a sniper rifle for medicine—the goal is to hit the target (cancer) while missing the surrounding healthy people (your organs).

Here are the different ways “External Radiotherapy” (radiation from a machine outside your body) is delivered, explained simply:

1. 3D-CRT (The 3D Map)

Doctors use CT or MRI scans to create a 3D model of your tumor. They then shape the radiation beams to match that exact size and shape from different angles. It’s like tailoring a suit to fit perfectly.

2. IMRT (The Precision Beam)

This is an upgrade to 3D-CRT. Instead of one solid beam, it uses many tiny “beamlets” that can change their strength (intensity). This is great for tumors that are near very sensitive organs because it can “curve” the radiation around them.

3. VMAT (The Continuous Arc)

With this method, the machine doesn’t just stop and shoot from one spot; it continuously rotates around you in a circle while giving the treatment. This makes the session much faster while remaining very accurate.

4. Stereotactic Therapy (The “Zap”)

This uses extremely high doses of radiation with pinpoint accuracy. It is often used for very small tumors.

• SRS: Used for the brain (usually just 1 session).

• SRT: Used for brain/spine (over a few sessions).

• SBRT: Used for the body (lungs, liver, etc.).

5. IGRT (The “Check-Before-You-Shoot”)

Since your organs move slightly when you breathe or digest food, IGRT takes a quick scan right before the treatment starts. This confirms the tumor is exactly where the machine thinks it is before the radiation is turned on.

6. SGRT (The “No-Tattoo” Option)

In the past, patients often needed tiny permanent tattoos on their skin to help the machine align correctly. SGRT uses 3D cameras to track your skin surface in real-time, so no tattoos are needed.

When is it used?

• To cure: Destroying the cancer completely.

• To help other treatments: Shrinking a tumor before surgery or killing remaining cells after.

• To help with symptoms: Reducing pain or discomfort if the cancer cannot be fully cured.

What about side effects?

Because radiation can sometimes touch healthy cells, you might feel:

• Tired (fatigue)

• Skin changes (like a mild sunburn)

• Hair loss (only in the area being treated)

• Nausea or loss of appetite

Choosing the right one: Your doctor picks the technique based on where your cancer is located and your general health. Each method is designed to be as safe and effective as possible for your specific situation. For more information about Radiotherapy for Cancer Treatment in Malaysia, please visit https://www.thomsonhospitals.com/articles/what-are-the-types-of-external-radiotherapy-for-cancer-treatment/