Glossary of Radiation Types

Health Monitor Staff
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Radiation therapy involves destroying cancer cells by targeting them with high-energy radiation (such as X-rays or gamma rays)—a painless procedure. There are many different types of radiation therapy available. Talk to your radiation oncologist about which is right for you.

3-dimensional conformal radiation therapy (3D-CRT):
Three-dimensional images of the prostate and surrounding areas are taken prior to treatment to determine their locations. Computer software is then used to identify the best angles at which the beams of radiation should be aimed so that it can conform to the shape of the area being treated.

Accelerated radiation:
A radiation schedule in which the total dose is given over a shorter period of time. Compare to hyperfractionated radiation.

Adjuvant therapy: "Add-on" treatment aimed at killing stray cancer cells. Radiation therapy often is used as an adjuvant to surgery.

Radioactive seeds are implanted into the prostate itself; low-dose seeds may be left within the prostate, while higher dose seeds are typically left there for only a short time. Also called internal radiation therapy.

Cyber knife:
Beams of high-dose radiation are delivered to the tumor from almost any direction. The system is able to track the tumor’s position and automatically adjust if needed.

Gamma rays:
High-energy rays that come from a radioactive element such as cobalt-60 or radium.

Helical TomoTherapy
: A newer form of intensity modulated radiation therapy (IMRT) in which the radiation is directed from a doughnut-shaped machine that spirals around the body.

High-dose-rate (HDR) brachytherapy:
A type of internal radiation in which the radioactive source is in place for only a short time and then removed. This may be repeated several times over a few days to weeks. See brachytherapy.

Hyperfractionated radiation:
A radiation schedule in which the radiation is given in smaller doses and more than once a day, but the overall length of treatment is the same. Compare to accelerated radiation.

Intensity modulated radiation therapy (IMRT):
An advanced method of conformal radiation therapy in which photon (X-ray) beams are aimed from many directions and the intensity (strength) of the beams is controlled by computers. This allows more radiation to treat the tumor, while reducing the radiation to healthy tissues.

Image-guided radiation therapy (IGRT):
Tumors can move because of breathing or other bodily movement; IGRT helps locate and target the tumor’s exact location at the time of treatment to ensure precise delivery of radiation.

Proton beam therapy:
Similar to IMRT in that it delivers precise radiation, but instead of photons, protons (charged particles found in an atom’s nucleus) are used to treat the cancer.

TomoTherapy: Scanning technology is used to determine the tumor’s shape and location, and while you're lying on your back, rotating radiation beams are aimed at tumors so that treatment can be delivered continuously. These are typically daily treatments that last about 20 minutes each.

May 2013