What Is Intensity Modulated Radiation Therapy (IMRT)? Thumbnail

What Is Intensity Modulated Radiation Therapy (IMRT)?

Intensity Modulated Radiation Therapy (IMRT) is a type of external beam radiation therapy. With IMRT your doctor uses a computer to plan the exact dose (or amount) of radiation that is aimed at your prostate cancer. It is one of the most precise forms of radiation therapy available and has proven very successful for the treatment of prostate cancer. The computer uses information about the size, shape, and location of your prostate cancer to figure out how much radiation is needed to kill your prostate cancer cells. IMRT uses high doses (or amounts) of radiation to kill your prostate cancer cells while protecting the healthy cells that surround your prostate cancer.

The Procedure

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.

The Role Of IMRT In Treating Prostate Cancer

IMRT is standard treatment now for treating localized prostate cancers and is often also used after an operation where the surgery (radical prostatectomy) has not removed all the cancer cells. IMRT allows higher doses to the prostate with a higher chance of controlling the cancer (cure). It also means that the lymph nodes can be more easily treated with reduced side effects. The main organ close to the prostate that sometimes limited the dose that could safely be delivered is the rectum (lower bowel). IMRT allows the amount of radiation in the high dose area to be minimized. This means short and long-term side effects have become significantly less common.

Side Effects

There are several side effects that you may have during or after your IMRT treatments. They are urinary problems, bowel problems, erectile dysfunction or impotence (difficulty in getting or keeping an erection of the penis), skin problems, loss of appetite and tiredness. Remember, that IMRT treatments are focused on your prostate cancer. This protects the healthy cells around your prostate, which means you may have fewer side effects and that the side effects you do have won’t be as severe.

Following Treatment

You will be able to leave and return to your normal daily activities following each treatment. IMRT will not make you radioactive and you don’t have to stay away from other people because of your treatment. However, you should contact your doctor if you experience any side effects you may have during or after your treatment. In many cases your doctor can prescribe medications or suggest treatments that can help to alleviate any complications.

Dr. David Samadi | Robotic Prostate Surgeon


ProstateCancer911.com is a resource created by Dr. David Samadi in order to raise awareness and get more men to receive prostate cancer treatment. The information is strictly general and you should always discuss with your doctor issues concerning your health.


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