Institute Is First In Oregon To Offer Patients The Most Advanced Technology For Prostate Radiation

02/23/11  Portland, Ore.

The new system, Calypso, works like a global positioning system precisely targeting prostate cancer - it's Star Wars technology. The scans allow radiation treatments to zero in on the tumor with millimeter precision.

Mark Graham lays perfectly still on the treatment table in the newly expanded Oregon Health & Science University Radiation Oncology unit. The lower half of Graham's body is snuggled into a customized vacuum-lock cradle, much like a form fitting bean bag. The cradle is specially made to mold around Graham's body and keep him from moving. Three infrared cameras that act like satellites in space are trained on him. Two radiation technicians carefully line up the new Calypso, a global positioning system for the body, readying Graham for  targeted radiation to his cancerous prostate tumor. Then, the linear accelerator, which is about the size of an SUV, unfolds its slab-like arms toward Graham, ready to deliver pinpoint radiation to the prostate cancer cells.

"It's actually kind of fun. It's like being in a Star Wars sequence," said Graham, 62, of Bend, Ore.

Graham is one of the first patients SU to have his prostate cancer treated with the cutting-edge Calypso unit at OHSU. It works much the same as a car's global positioning system (GPS). Three electromagnetic markers, each smaller than a grain of rice, are implanted in the prostate. They emit signals that focus the beams of radiation for treatment. The radiation can then target the cancer cells with supreme accuracy and leave the healthy cells alone. It allows the radiation oncologist to pinpoint a prostate tumor's location with surgical accuracy while continuously monitoring its position during radiation treatment. Because of the higher accuracy, higher doses of radiation can be delivered while simultaneously reducing side effects and offering patients a better chance for a cure.

"In some men, the prostate moves a lot. The beacons report the exact location and the motion patterns inside the body over time. We don't need to treat a large area to compensate for movement.  We can treat only the cancerous prostate. Also, there are potentially fewer side effects and higher cure rates because the Calypso allows the radiation beam to stay focused on the prostate throughout the treatment," said Arthur Hung, M.D., assistant professor of radiation oncology, OHSU School of Medicine; and member of the OHSU Cancer Institute.

Most people don't realize that internal organs move. A mere burp or even digestion can cause the prostate to shift an inch. Previously radiation techniques involved imaging the tumor and prostate using implanted gold markers, and X-rays or ultrasound scans before each radiation session.  But these aren't effective once the treatment starts. The Calypso allows a continuous scan so that if the prostate moves, the linear accelerator will stop until the target is back in the crosshairs.

Radiation therapy is used to treat approximately 1 million cancer patients in the United States each year, and is one of the most effective cancer therapies. Each year, 218,000 men are diagnosed with prostate cancer, according to the American Cancer Society. In prostate cancer treatment the most common side effects arise when the radiation beam misses the prostate but irradiates adjacent healthy organs, causing complications like impotence, urinary incontinence and rectal bleeding. Therefore, doctors must guard against damaging healthy tissues that surround the tumor caused by misalignment and unpredictable tumor motion.

Graham's treatment from start to finish took about 20 minutes. He is almost finished with his radiation treatment.

For now, OHSU radiation oncology is only using the Calypso technology for prostate cancer, but it may eventually be used for other cancers.

This new technology is made by Calypso Medical Technologies Inc. of Seattle.
 

The OHSU Cancer Institute is the only cancer center designated by the National Cancer Institute center between Sacramento and Seattle. It comprises some 120 clinical researchers, basic scientists and population scientists who work together to translate scientific discoveries into longer and better lives for Oregon's cancer patients. In the lab, basic scientists examine cancer cells and normal cells to uncover molecular abnormalities that cause the disease. This basic science informs more than 200 clinical trials conducted at the OHSU Cancer Institute.