Radiotherapy tattoos or skin markings help make sure external radiotherapy treatment is accurate.
During your radiotherapy planning session, your radiographer (sometimes called a radiotherapist) might make between 1 to 5 permanent pin point tattoo marks on your skin. For some types of radiotherapy, for example, electron treatments, you won't have tattoo marks.
Your radiographer uses the tattoos to line up the radiotherapy machine for each treatment. This makes sure that they treat exactly the same area each time.
Your radiographer might also draw marks around the tattoos with permanent ink pen. This helps to highlight the tattoos so they can be seen more easily in the room where you have treatment, which can be dark. Don't try to wash them off.
The pen marks will start to rub off in time. They can rub off on your clothes or when you wash. Tell your radiographer if that happens. They can redraw them the next time you have treatment.
You may want to wear older clothes next to your skin in the treatment area. Or you can ask your radiographer after each treatment to remove the marks with a wipe.