Intensity Modulated Radiation Therapy Overview

Radiation therapy uses radiation to kill cancer cells and shrink tumors. Some normal cells will be damaged with radiation. The goal of radiation therapy is to kill as many cancer cells as possible, while limiting damage to healthy cells.

Intensity modulated radiation therapy (IMRT) is a treatment for cancer. It uses radiation beams of different intensities. The beams deliver appropriate doses of radiation to the tumor and reduce the dose to nearby healthy tissue.

Radiation of Tumor © 2009 Nucleus Medical Media, Inc.

Prior to Procedure

Planning for IMRT is complex and generally takes 2-5 days. Planning may include:

• Physical exam
• Coming in one or more times for imaging tests to identify exactly where the radiation beams will be focused; imaging tests used may include:

• X-ray—a test that uses radiation to take a picture of structures inside the body
• CT scan —a type of x-ray that uses a computer to make pictures of structures inside the body
• MRI scan —a test that uses magnetic waves to make pictures of structures inside the body
• PET scan —a test that uses a special camera to view structures inside the body after a radioactive solution is injected into a vein
• CT/PET scan—a simultaneous fusion of both studies that provides increased accuracy over either study alone
• Marking the locations on the skin where the radiation will be focused to guide the therapist
• Being fitted for a localization device (eg, mask, body frame), which can help target accuracy
• Using ultrasound or implanted markers to track the position of the tumor

Description of the Procedure

Using the marks made on your skin as a guide, the radiation therapist will position you on the treatment table. Films or ultrasound may be used to check the accuracy of the treatment setup. The therapist leaves the room to control the movements of the radiation machine. The treatment delivers radiation in a three-dimensional manner. This will help to conform as closely as possible to the shape of the tumor. The healthy tissue receives smaller doses of radiation than the tumor.

You will be asked to remain still during the radiation treatment. You may breathe normally. In general, you will not feel or sense anything during treatment. However, the machine can be stopped if you feel sick or uncomfortable. The therapists will be monitoring you on a TV camera. You will be able to communicate to them should you need to.

Immediately After Procedure

You will be able to leave and resume your normal daily activities. Receiving IMRT does not make you radioactive, and you do not need to avoid being around other people because of the treatment.

How Long Will It Take?

Each session will take 15-30 minutes. Patients are typically scheduled for IMRT five days per week for 4-8 weeks.

How Much Will It Hurt?

Holding one position may become a little uncomfortable, but it is not painful.

Post-procedure Care

During treatment, your doctor will want to see you at least once a week. You may have blood tests or other studies performed.

After your treatment is completed, you will come in for regular visits to monitor for side effects and healing and check for signs of recurrent disease. You may require further testing, medicine or rehabilitative treatment. Be sure to follow your doctor’s instructions.

RESOURCES:

American Cancer Society
http://www.cancer.org/

National Cancer Institute
http://www.cancer.gov/

CANADIAN RESOURCES:

BC Cancer Agency
http://www.bccancer.bc.ca/

BC Health Guide, British Columbia Ministry of Health
http://www.bchealthguide.org/

References:

External radiation therapy. American Cancer Society website. Available at: http://www.cancer.org/docroot/ETO/content/ETO17xexternalradiation_therapy.asp . Accessed November 15, 2005.

IMRT. International Radiosurgery Support Association website. Available at: http://www.irsa.org/imrt.html . Accessed November 15, 2005.

Intensity-modulated radiation therapy (IMRT). American College of Radiology and Radiological Society of North America website. Available at: http://www.radiologyinfo.org/content/therapy/imrt.htm . Accessed November 15, 2005.

Radiation therapy and you. National Cancer Institute website. Available at: http://www.cancer.gov/cancertopics/radiation-therapy-and-you/ . Accessed November 15, 2005.

Radiation therapy for cancer: questions and answers. National Cancer Institute website. Available at: http://www.cancer.gov/cancertopics/factsheet/Therapy/radiation . Accessed November 15, 2005.