OHSU

Intensity-Modulated Radiation

Intensity-modulated radiation therapy, or IMRT, is a type of external beam radiation therapy.

In IMRT, the radiation beam is shaped to match the tumor. This is similar to 3D CRT. Using IMRT also allows your doctor to adjust the amount of radiation delivered to different areas of the tumor. Areas with more cancer cells receive more intense radiation, while areas with less cancer get less intense radiation beams.

With IMRT, your treatment team can control the amount of radiation sent to each part of the tumor. This helps protect healthy tissue. It also makes cancer treatment more effective, because a higher radiation dose can be sent to the areas that need it most. The precise control of IMRT can mean fewer side effects.

 

Calypso® For Prostate Cancer Treatment

Calypso® radiation technology is used during intensity-modulated radiation therapy (IMRT) used to treat prostate cancer. The Calypso® system allows doctors to monitor the tumor continuously during radiation therapy. Using MRI and CT scans of the tumor, your radiation oncologist will prescribe the correct dose of radiation for each area of cancer. Areas with more tumor tissue will receive more radiation. Areas that need less treatment will get a lower dose.  

Because moving or even breathing during treatment can change the tumor’s position, a system that keeps radiation directed at the tumor is important. Before Calypso® treatment, tiny sensors called Beacon® transponders are placed inside the prostate gland. The sensors help the radiation beam track the tumor tissue, avoiding healthy areas nearby.

Currently, Calypso® is used only for prostate cancer treatment. In the future, doctors might use it to treat tumors throughout the body.

 

Cancers Treated Using IMRT