Patient Center

Terminology 

During your treatment, you may hear various medical terminology used when describing radiation 
therapy. Below is a list of common terms that may be related to your care. We hope these descriptions 
help, but if you have any questions understanding your treatment, please let us know. 
 
Bolus 
A tissue-equivalent material used to change the surface distribution of a radiation beam. 
 
Brachytherapy 
The use of radioactive sources placed directly into a tumor bearing area to generate local regions of high 
intensity radiation. 
 
Chemotherapy 
The use of drugs or medications to directly attack cancer at the cellular level by disrupting the cell 
metabolic or reproductive cycle. 
 
Fractionation 
The schedule of fractions of treatment as it is delivered. This is usually expressed as the number of 
fractions or treatment sessions delivered over a specific period of time. 
 
Hyperfractionation 
Any technique of radiation treatment that delivers more than one treatment session per day. 
Hyperfractionation is normally done twice and usually is separated by a period of 4 to 6 hours. 
 
Palliation 
The use of radiation therapy in an attempt to decrease symptoms such as pain, bleeding or other 
dysfunctions. This sometimes results in the prolongation of life, but the main goal is to improve the quality 
of life. 
 
Portal Films 
X-rays taken during the delivery of radiation treatment utilizing the treatment beam of the machine. Portal 
films demonstrate the exact shape, size and area covered by each individual treatment beam during an 
actual treatment. 
 
Treatment planning 
The cognitive process carried out by the physician to determine all of the parameters in a given course of 
radiation therapy.