Quick and painless, external-beam radiation has long been used to destroy cancer cells. The latest methods—Intensity Modulated Radiation Therapy (IMRT) and Image-Guided Radiation Therapy (IGRT)—provide the most advanced technology for fighting cancer. Used alone or together, these therapies allow higher doses of radiation to be delivered with greater precision and accuracy without destroying surrounding, healthy tissue. For colorectal cancers this precision may reduce the incidence of side effects such as frequent bowel movements, diarrhea, abdominal cramping, pressure or discomfort in the rectal area, more frequent urination and burning with urination.
For patients, IMRT/IGRT means:
IMRT is a specialized radiation therapy that uses powerful treatment planning software to calculate precise beam angles, shapes and exposure times tailored to each tumor. The radiation beam can be broken up into many smaller beams and the intensity of each small beam can be adjusted individually. This may allow a higher dose of radiation to be delivered to the tumor with less risk to nearby healthy tissue, potentially decreasing the duration of treatment and increasing the chance of a cure.
Tumors can move during a course of treatment. IGRT combines imaging and treatment capabilities on a single machine. This way, tumors can be tracked between, as well as during, treatments, allowing radiation to be focused more precisely. Images captured before each radiation session are compared to previous sessions so that clinicians know the exact location of the tumor each time. IGRT software also accounts for breathing and motion during treatment, ensuring the radiation stays focused on the tumor.