Intensity-Modulated Radiation Therapy (IMRT)
Intensity-modulated radiation therapy (IMRT) is an advanced type of radiation therapy used to treat cancer and noncancerous tumors.
IMRT uses advanced technology to manipulate photon and proton beams of radiation to conform to the shape of a tumor.
IMRT uses multiple small photon or proton beams of varying intensities to precisely irradiate a tumor. The radiation intensity of each beam is controlled, and the beam shape changes throughout each treatment.
The goal of IMRT is to conform the radiation dose to the target and to avoid or reduce exposure of healthy tissue to limit the side effects of treatment.
How is the procedure performed?
IMRT often requires multiple or fractionated treatment sessions. Several factors come into play when determining the total number of IMRT sessions and radiation dose. The oncologist considers the type, location and size of the malignant tumor, doses to critical normal structures, as well as the patient's health. Typically, patients are scheduled for IMRT sessions five days a week for five to eight weeks.
At the beginning of the treatment session, the therapist positions the patient on the treatment table, guided by the marks on the skin defining the treatment area. If molded devices were made, they will be used to help the patient maintain the proper position. The patient may be repositioned during the procedure. Imaging systems on the treatment machine such as x-ray or CT may be used to check positioning and marker location. Treatment sessions usually take between 10 and 30 minutes.