Doctors across the United States are beginning to use an alternative method to help detect breast cancer that a mammogram may have missed.

The screening technique injects radioactive liquid into a patient, ABC News said. After the liquid passes through the body, any cancerous cells can be detected because they absorb more of the radioactive material than surrounding, healthy cells.

Doctors said radioactive imaging is an alternative if women have dense breasts that could obscure cancer in a mammogram, ABC News said. They said the method, offered at 33 hospitals in the United States, does not replace a traditional mammogram.

Separately, researchers at University of Missouri-Columbia said preliminary findings indicate a 30-minute blood test could enable doctors to detect melanoma as it travels through the blood, WebMD.com said.

Melanoma is the deadliest type of skin cancer.

For their experiment, researchers drew blood from a patient with melanoma that had spread. The scientists aimed a laser at the sample to produce sound from any melanin, indicative of melanoma cells, present in the blood, WebMD.com said.

Copyright 2006 by United Press International