PHILADELPHIA, Feb. 13 (UPI) -- U.S. medical scientists have started an 18-month study of a new liver cancer treatment that involves the use of millions of tiny, radioactive beads.

The Thomas Jefferson University Hospital researchers said the technique, called radioembolization, is being used for the first time in patients with hepatocellular carcinoma, or primary liver cancer.

Dr. Brian Carr, an oncology professor at the university's medical college, said the trial also includes patients from the University of Texas' M.D. Anderson Cancer Center in Houston and the University of Pittsburgh.

Carr said the tiny beads, or "microspheres," containing the radioactive isotope Yttrium-90 are injected into the liver's hepatic artery. The microspheres, in addition to blocking blood flow to the tumor, emit radiation directly to the cancer, sparing healthy tissue.

Although the treatment doesn't cure the cancer, it can shrink tumors and help patients live longer.

"Ideally, if the radioembolization trial is successful, many of these patients would have their liver tumors shrunken to the point where surgery is possible," said Carr. "It would be a significant contribution to the field if we could downstage the tumors so we could do more transplants, which is the only cure."