IMRT: Frequently Asked Questions

Image-Guided Intensity Modulated Radiation Therapy (IMRT) for Prostate Cancer

Q: My urologist says my biopsies showed prostate cancer.  What do I do now?
A: A wide range of good treatment options exist for prostate cancer.  Talk to your urologist about which treatment options are most suitable for you.

Q: Radiation therapy is an option for treatment of my prostate cancer.  How does it work?
A: Radiation therapy is a time proven treatment for cancer.  Most tumors are more sensitive to radiation than the surrounding normal structures (your bladder and rectum) and thus can be effectively treated.

Q: You have used the term IMRT.  What does it mean?
A: Intensity modulated Radiation Therapy (IMRT) is a technique to improve external delivery of radiation therapy by a linear accelerator.  Instead of maintaining a uniform radiation beam as used in conventional or 3-dimensional radiation, IMRT uses devices within the machine to divide the radiation beam into multiple smaller beams called beamlets that can have different intensities (modulated) within the area being treated.  This allows more precise delivery of radiation doses to the tissues within the target area allowing increased doses to the prostate while sparing the surrounding bladder and rectum.  This is important as several recent medical studies have suggested that higher prostate doses are associated with increased curability.

Q: So what is all the excitement about Image-Guided IMRT and what is it anyway?
A: Image-guided radiotherapy represents one of the most significant technical advances in radiotherapy.  Image-guided radiotherapy improves our ability to give sufficient radiation doses to sterilize tumors while protecting normal structures and thus potentially decreasing the risk of complications.

Q: How do you get set up for IMRT?
A: Several steps are required to set up your therapy.  Prior to beginning your treatment, you will come to our office for imaging.  Generally speaking, a Cat Scan of the pelvis is performed although occasionally additional scans including MRI are obtained.  At the time of the CAT scan, the staff will place you in a treatment position.  A small amount of dye may be introduced into the urethra at this time.  The whole process generally takes about one hour.  During the next few days, the planning process takes place using the images from the CAT scan.  You do not need to be present at this time.  Your IMRT treatment plan is prepared by your physician in conjunction with the medical staff.

Q: How is the x-ray treatment given?
A: Your radiation treatments are administered by a trained therapist.  The treatment is given by a linear accelerator while you lie on a couch.  The arrangement is quite “roomy” unlike that of a CAT scan or MRI.  The actual treatment is painless.  When receiving the treatment, you are monitored by a closet circuit TV ,and you may converse with the staff by intercom.

Q: But what about Image-Guided Therapy?
A: While Intensity Modulated Radiation Therapy (IMRT) is very accurate, it does have its shortcomings.  The entire plan is based on your initial CAT scan image, which fixes the position of the internal organs.  However, the prostate, bladder, rectum and other organs display some movement and there can be a variation in position of the organs relative to the initial CAT scan of several millimeters to as much as a centimeter or two (1 cm = 4/10 inch).  To counter this organ movement, we acquire your image on a frequent basis (often daily).  You are placed on the treatment couch in the treatment room in the usual way.  However, just prior to beginning your treatment, an image is obtained to determine the relative positions of the internal organs.

Q: What do you do with the images obtained before receiving radiation treatment?
A: There are two types of images ,which can be obtained in the treatment room.  The first is similar to the initial CAT scan used to create the treatment plan.  The staff then uses this new image by superimposing it over the original CAT scan.  Notation can be made of any internal organ movement and the treatment position can be adjusted to accommodate and thus increase the accuracy of the treatment.  Increased accuracy over the seven or eight weeks of treatment can be associated with an increased potential for cure with a decreased risk of side effects and complications.
The second form of image-guided therapy requires your urologist to place several insert marker seeds in the prostatic area.  These marker seeds are then visualized just prior to therapy in the treatment room and compared to the initial seed position.  Adjustment can then be made.

Q: This treatment sounds interesting, but can I afford it?
A: The treatment is a Medicare reimbursed therapy and is approved by most private insurance carriers.  Your individual plan may be subject to co-pay and/or a deductible amount.  Our staff will answer any questions, and we will do our best to help you through the process.