Robot-assisted brachytherapy for treating prostate cancer

In the first-of-a-kind clinical trial, a robot will be used to place therapeutic radioactive seeds in prostate cancer patients. The National Cancer Institute-supported study, which will enroll 14 patients, has just opened at Thomas Jefferson University Hospital.

The robot has been designed by Thomas Jefferson University scientists to provide the steadiest and most precise method possible to implant scores of the seeds directly at the site of a cancerous tumor in the prostate gland, eliminating the possibility of human error, says Adam Dicker, MD, PhD, Professor and Chairman of the Department of Radiation Oncology at Jefferson.

This will be the first test in the U.S. and worldwide of robot-assisted brachytherapy for treating prostate cancer, he says. The federal Food and Drug Administration has approved Thomas Jefferson University's application to test the device in patients.

Prostate brachytherapy, which requires accurate insertion of some 60-120 radioactive seeds in very specific places in the prostate, involves a high degree of clinical skill and attention to detail, he says. "When performed with good quality, brachytherapy offers excellent cure rates compared to surgery, external radiation and proton therapy," Dr. Dicker says. "However, poorly placed seeds may lead to urinary and rectal toxicities."

Currently, physicians use a plastic or metal template with holes in which to insert 15-20 needles that contain radioactive seeds into the prostate gland. But because this grid is thin, it is difficult for a person guiding it to push it smoothly and straightly through glandular tissue. "The template forms a pivot point of sort, so the needles, which are unsupported, can twist ever so slightly," he says. "Getting the seeds to the right place is very important because of the side effects that can occur from the radiation they emit."

"With its motorized controls and imaging feedback, the robot can systemically place the seeds in a way we believe is more consistently accurate than a human can be," says Yan Yu, PhD, Professor and Director of the Medical Physics Division in the Department of Radiation Oncology.

Dr. Yu led a team of medical physicists, engineers, radiation oncologists, radiologists and urologists who spent seven years developing the robotic system, which is called EUCLIDIAN. It incorporates high resolution ultrasound image processing, dose planning using genetic algorithms, 3D visualization, smart needle rotation for reducing tissue deformation and prostate displacement, and force feedback from nano-sensors installed at various points on the robot. Needle insertion and seed delivery are fully automatic.

"The robot is controlled by a physician via a handheld controller and a computer interface," he says. "It is capable of reverting to manual needle and seed insertion any time the physician desires."

Dr. Yu says the robot has been described in 30 scientific papers by the Jefferson team, and the intraoperative software that operates the robot has been under development for more than 15 years and has been reported in 20 scientific papers.

"Robotic brachytherapy combines the expertise of a multi-disciplinary clinical team led by radiation oncologists, with the most sophisticated robot technologies available today, to aim for the ultimate goal of delivering the best possible dose distribution each time for every patient, and verifying this before the patient leaves the procedure," said Dr. Dicker, who is the principal investigator of the EUCLIDIAN clinical trial at Jefferson.