WASHINGTON (HealthDay News) -- Positron emission tomography (PET) imaging can identify an aggressive form of kidney cancer and may eliminate the need for biopsy in some patients, U.S. researchers report.

"Patients who have kidney tumors may now be able to have an imaging examination that will enable the physician to determine whether the tumor is aggressive enough to warrant immediate surgery," study lead author Chaitanya Divgi of Memorial Sloan-Kettering Cancer Center and the Ludwig Institute for Cancer Research in New York City said in a prepared statement.

"This should avoid needless surgery in about a quarter of all patients who present with kidney tumors," Divgi said.

In this study, researchers labeled a monoclonal antibody known to bind to the more aggressive "clear cell" subtype of kidney cancer with a PET tracer called iodine-124. Then they assessed absorption of the tracer in kidney masses of 26 patients.

Using this method, the researchers identified 15 of 16 clear-cell carcinomas, while nine of the nine patients with other subtypes didn't absorb the tracer.