3D conformal radiation therapy is a cancer treatment that shapes the radiation beams to match the shape of the tumor.

In the past, radiation beams only matched the height and width of the tumor — exposing healthy tissue to radiation. Advances in imaging technology have made it possible to locate and treat the tumor more precisely.

Conformal radiation therapy uses the targeting information to focus precisely on the tumor, while avoiding the healthy surrounding tissue.

This exact targeting makes it possible to use higher levels of radiation in treatment. More radiation is more effective in shrinking and killing tumors. 3D conformal therapy is — in many ways — like intensity-modulated radiation therapy (IMRT). They both target cancer while sparing healthy tissue.

The radiation oncologist will decide which therapy is best for you, based on your tumor’s shape and location.

How Do You Deliver 3D Conformal Radiation Therapy?

Before treatment, you will have a radiation planning (or simulation) session, where a therapist will make a custom-fit mold.

The radiologist will take a 3D image of your tumor, often using one of the following imaging methods:

• CT (computed tomography) scan
• MRI (magnetic resonance imaging)
• PET (positron emission tomography) scan
• PET-CT scan

Then, a computer program analyzes the 3D image and designs radiation beams that conform to the shape of the tumor.

3D Conformal Radiation Treatment: What to Expect

A 3D conformal radiation treatment session takes about 30 minutes total.

The therapist sets up the treatment according to the 3D images of the tumor and the info from the simulation.

• You lie in the mold on the x-ray table
• During treatment, beams from several directions precisely match the tumor’s height, width, and depth
• The linear accelerator moves in a circular fashion around the tumor area
• The actual treatment lasts only a few minutes

Your oncologist will decide your treatment schedule, including how many times per week you will need to repeat radiation treatment.

What Are the Benefits of 3D Conformal Radiation Therapy?

A number of cancer types have seen improved outcomes from 3D conformal radiation therapy, including:

• Brain cancer
• Head and neck cancer
• Liver cancer
• Lung cancer
• Prostate cancer