GPS for the body
New device helps pinpoint delivery of radiation during prostate therapy
By Kathy Day (Special to the North County Times Advertising Department)
(NCT - July 15, 2012)
If you use a GPS to find your way around town, you probably know it’s a pretty effective invention. But you may not know that there’s now a “GPS for the Body,” and it is being used exclusively in San Diego County by Genesis Healthcare in Escondido to help radiation oncologists treat prostate tumors.
Called Calypso and manufactured by Varian Medical Systems, the device helps guide the delivery of the radiation. Tiny electromagnetic transponders — each smaller than a grain of rice — are placed in the patient’s prostate gland or the post-operative prostatic bed. When the treatment starts, they are activated to emit a radio signal to the system, indicating the location of the target and showing any movement from breathing, coughing or digestion during the treatment.
“The technology is the only real-time image that allows us to track the movement of the organ,” explained Dr. Reza Shirazi, who earned his bachelor’s degree in electrical engineering at Cal State Los Angeles and his master’s in applied physiology and medical degree from The Chicago Medical School at the Rosalind Franklin University of Medicine and Science.
Since he studied satellite communications as an undergraduate, “the world of robotics, engineering and math have come a long way,” he said as he talked about the changes that the Calypso system have brought to prostate cancer care.
“Now we are actually seeing where we are treating,” he said.
In the past, treatments were “like crossing our fingers and closing our eyes and giving the radiation as fast as we could before the prostate moved,” he added.
He cited the example of a gas bubble passing through the digestive system, which can push the prostate 1.5 centimeters up and down. When that happens, the tumor moves out of the path of the radiation beam, possibly exposing noncancerous areas instead.
From day to day, the same patient can have different movements that are affected by such factors as whether he ate a certain type of food, Shirazi said.
Now, when the Calypso System “sees” the bubble coming, the therapists can stop the treatment momentarily and restart it when it has passed.
Shirazi noted the increased accuracy means fewer side effects and less “collateral damage” to surrounding healthy tissue and organs.
That’s significant because side effects like urinary, bowel and sexual dysfunction are possible after radiation for prostate cancer, according to a study in the journal Urology, published in May 2010.
Although the Calypso System is approved only for use in prostate cancer, Shiraz said, other applications are on their way through the Food and Drug Administration pipeline.
In addition to its Escondido radiation oncology office at 701 E. Grand Ave., Suite 200 and its Palomar Urology office at 251 S. Hickory St., Suites 114-116, the medical group has 13 other offices where a full range of health services for treatment of prostate cancer and other cancers and urological conditions.