Every course of radiation therapy is designed to suit the particular needs of the person receiving it, so you will usually be asked to make a preliminary visit to the treatment center to have your course of treatment planned. The radiation oncologist and radiation therapists will do this (in conjunction with x-rays and scans, using a machine called a simulator). Your skin will be marked with colored pens to define where you will have your treatment. In addition, some minute permanent marks will be made using a special dye and a tiny pin prick.
These marks will enable the radiation therapists to identify exactly the right area at every treatment session. If a head shell has been made for you the guidance marks will be put on the shell rather than on your skin.
If you are having radiation therapy to your mouth and/or throat you will need a dental assessment at this stage as you may require some dental treatment before you start your radiation therapy.