Intensity-Modulated Radiation Therapy (IMRT)

As part of our mission to offer state-of-the-art therapies, Saint Francis Hospital has been a leader in offering Intensity-Modulated Radiation Therapy (IMRT).

WHAT IS IMRT? 

IMRT represents the next step in the evolution of radiation therapy. IMRT offers the Radiation Oncology Physician the ability to deliver tightly conforming high doses of radiation precisely to the tumor while sparing adjacent tissues, irrespective of the shape of the tumor. Using this technique, we can now treat many tumors safely with higher doses of radiation, which should hopefully result in improved cure rates.

HOW IS IMRT ACHIEVED? 

The precise 3-dimensional shaping of the radiation dose with IMRT is accomplished by using multiple shaped beams focused on the tumor, as in 3-D conformal radiation. With IMRT, each beam has the intensity of the radiation varied, or modulated, to deliver varying amounts of dose. These hundreds of “beamlets” are made possible by using computer-controlled multileaf collimators which are mounted inside the linear accelerator. These move continuously during the treatment to deliver varying doses of radiation within the field. (2 pics of pelvis CT, modulated beams)

 

 

WHAT TYPES OF CANCER IS IMRT USED FOR? 

We are currently using IMRT for types of cancer in which it has been demonstrated to offer significant benefits. This includes prostate cancer, head and neck cancers (which includes tongue, tonsil and throat cancers), brain tumors, and some lung and pancreatic cancers. We are also investigating the use of IMRT for breast, cervix, and uterine cancers.

 

WHAT CAN I EXPECT IF I RECEIVE IMRT? 

Before any IMRT treatments are delivered, an extensive planning process needs to be performed. After your initial consultation with the Radiation Oncologist, you will be scheduled to have a special CT scan performed in the Radiation Oncology department. This is necessary even if you recently had a CT scan elsewhere. This “planning” CT scan will be performed with you in the exact same position that you will be in for each of your radiation treatment.

Many times we will make custom-fabricated molds or casts, which will be used each day for your treatment. The purpose of these is to help ensure that you are in the exact same position each day, to achieve the greatest precision. Following the completion of the scan, you will have three marks placed on the skin, which will be used for alignment for your upcoming treatments.

Your next appointment will be for 5-10 days later. During this time period, the Radiation Oncologist, along with the Medical Physicists and Dosimetrists perform the complex computer planning necessary to develop the optimal IMRT plan. When you return, we will take x-ray pictures to confirm the alignment. The treatments will then start either that day, or the following day. Each treatment will consist of the radiation machine gantry moving around you, for as many as nine different positions. At each gantry position, the radiation beam is turned on, and the multileaf collimators will automatically begin moving inside the machine to deliver the IMRT. Typically each treatment will take 15-20 minutes. You should feel nothing during each treatment. Most courses of IMRT will involve treatments given Monday-Friday, 5 days per week, for a total of 25-43 treatments (5-8 ½ weeks).

DOES INSURANCE COVER IMRT TREATMENTS? 

Most insurance plans, including Medicare, cover the costs for IMRT. As with any medical procedure, it is always a good idea to check with your insurance carrier to confirm that the costs are covered, and that any necessary pre-approval requirements have been met.

IS IMRT RIGHT FOR ME? 

IMRT is not appropriate for all cancers. Types of cancers where IMRT offers the most benefit are ones which are relatively small and localized, which are better able to be targeted with pinpoint precision. Speak to your physician to see if it may be right for you.

IMRT LINKS 

Varian Smart beam: 

ASTRO patient information site: