Dr. Maria Kelly uses an ultrasound to pinpoint the location of the prostate. Because the gland can move within the body, knowing its exact location allows doctors to give dosages of cancer-treating radiation without damaging surrounding tissue.

November 20, 2002 -- For patients with prostate cancer, a new imaging technique is helping them get just the right dose of radiation delivered to the tumor. This accurate delivery helps to spare healthy tissue surrounding the tissue from the effects of radiation.

The prostate gland can move each day in the body by as much as 1-2 centimeters. For this reason, radiation oncologists at the University of Virginia are using B-mode acquisition and targeting (BAT) to pinpoint the precise location of the gland before delivering cancer-killing radiation.

BAT ULTRASOUND

"BAT, which is an ultrasound technology, is a painless method that does not use any radiation as we determine the daily position of the prostate gland," says Dr. Mari Kelly, chair of the U.Va. Department of Radiation Oncology. "With the BAT imaging technology, we can make sure the tumor gets the full dose of radiation while we keep the radiation field as small as possible to avoid healthy tissue." U.Va. is the first hospital in Virginia to offer this technology.

A typical schedule for radiation treatment of prostate cancer might be a daily dose of radiation for up to 35 or 40 days, Dr. Kelly says. Thus, delivering the least amount of radiation possible is an important goal.

LOCATING THE PROSTATE

BAT is used first to find the exact location of the prostate, and then the radiation treatment is given. Each day the patient receives radiation, the day’s BAT image is superimposed on the original planning images, which are made using computed tomography (CT), often with magnetic resonance imaging (MRI). This planning image maps a patient’s tumor and surrounding physical structures to make a computer-generated, 3-D reconstruction to be used in treatment planning.

Each treatment day, the radiation equipment is readjusted so that the BAT image aligns perfectly over the planning image. Images and equipment are rechecked for accuracy before radiation is delivered at the dosage needed for the patient. This way the patient receives personalized, up-to-the-minute imaging and treatment.

BAT AND IMRT IMAGING

At U.Va., BAT is being used in combination with intensity-modulated radiation therapy (IMRT) for prostate cancer patients. IMRT is an extremely precise form of radiation treatment that can vary dose intensity to the tumor and envelop the tumor with a precisely delivered dose of radiation while shaping the beam to carefully avoid healthy tissue. IMRT allows radiation oncologists to deliver a higher dose of radiation than traditional radiation therapy techniques.

Using BAT with IMRT helps to reduce the rate of complications in normal tissue and improve the patient's quality of life after treatment ends.

"IMRT in combination with BAT offers an alternative method of high-dose delivery to the prostate in patients who are not candidates for other treatment methods and may improve their outcome," Dr. Kelly says. "These technologies benefit prostate cancer patients, just as we have seen them provide tremendous benefits to patients with cases of head and neck cancer."For more information, contact Dr. Maria Kelly, chair of the U.Va. Department of Radiation Oncology, at 434-982-0777.