Radiation Therapy Tattoos

Author: Courtney Misher, MPH, BS R.T.(T)
Content Contributor: Allyson Distel, MPH
Last Reviewed: March 13, 2024

Before radiation treatments begin, you will go through a treatment planning process called "simulation." During this process, your radiation treatment team will measure your body and place marks on your skin.  These marks are permanent (won’t go away) and are called tattoos. The therapists use these tattoos to line you up for treatment every day.

In some cases, such as breast radiation, tattoos may be used to outline the treatment field and be placed in each corner of the field. Other times they are used with lasers to make sure your body is straight on the treatment table. In this case, the tattoo placement will not be related to where the treatment is being given.

What do the tattoos look like?

The tattoos are small dots, the size of a pinpoint or freckle. They are made using India ink (blue or black) or black light responsive ink (pink). The black light ink tattoos may appear pink on the skin but can be seen better using special UV flashlights. Often, the tattoos are placed in areas on the body that won’t be seen by others.

How are the tattoos done?

The tattoos are made by placing a small drop of ink on the skin and pricking the skin with a needle. The needle prick may feel like a pinch or a mosquito bite. It may be uncomfortable, but the feeling will go away. The needle does not go all the way into the skin, just through the first few layers of skin.

How many tattoos will I get?

You will get about 1 to 4 tattoos, but sometimes more are needed. In some cases, a second set of tattoos may be needed. This is often true if more than one area of the body is going to be treated or if your treatment plan changes.

Why are the tattoos permanent?

These tattoos are needed to make sure your treatment is given correctly. Since the tattoos are permanent, you won’t have to worry about them washing off when you bathe or shower. Also, if more radiation therapy is needed in the future, the tattoos are a permanent record of past treatments.

Can I get treatment without getting tattoos?

In some cases, because of cultural or religious beliefs, or psychosocial impacts, tattoos will not be used. Talk to your healthcare provider to see what choices you have. Rarely, tattoos will not be used.

Pictures of the tattoo process.

While on the CT simulation machine, laser beams are used to mark the treatment area with a marker.

Supplies for tattooing. The area is first cleaned with alcohol.

A drop of ink is placed on the mark.

A needle is used to prick the top layers of the skin, getting the ink under the skin and creating the tattoo.

The small bluish dot in the center of this image is the tattoo.


Related Blog Posts

December 12, 2023

Holiday Lights Are My Favorite Thing

by Courtney Misher, MPH, BSRT(T)

April 19, 2023

Happy Occupational Therapy Month

by OncoLink Team

June 9, 2022

Five Questions With…Michele.

by OncoLink Team