The European Union has granted marketing authorization to Axumin, an injectable radioactive agent used to detect prostate cancer that has recurred.

High levels or PSA, or prostate specific antigen in blood, can signal the return of prostate cancer. One way doctors can confirm a recurrence is using positron emission tomography, or PET scans, to try to spot it. Axumin, developed by Blue Earth Diagnostics, helps physicians who perform a scan detect high amino acid levels that can indicate a recurrence.

The U.S. Food and Drug Administration approved Axumin as a PET imaging agent for detecting prostate cancer recurrence in October 2016. Axumin is the first and only PET imaging agent to receive EU approval. It has also been authorized in Iceland, Liechtenstein, and Norway.

“We are delighted by the European Commission’s marketing authorization for Axumin, which is a major milestone for Blue Earth Diagnostics and underlines our commitment to develop innovative molecular imaging agents that inform and guide treatment decisions for physicians and their patients,” Jonathan Allis, Blue Earth’s CEO, said in a press release.

“Axumin is our first approved product in Europe, and we believe that it will benefit men with biochemically recurrent prostate cancer. We are now in discussions with potential manufacturing and distribution associates to make Axumin commercially available across Europe.”

Prostate cancer is of increasing significance worldwide. In the United States and in Europe, it is one of the most common cancers and among the leading causes of cancer deaths.

While most prostate cancer can be treated with success, the disease recurs in up to a third of patients. Recurrence is sometimes detectable only by a rise in PSA levels, but often the recurrence cannot be located by conventional imaging.

Axumin is a synthetic, radiolabeled amino acid that allows researchers to detect the location and extent of prostate cancer recurrence. Cancer cells can convey more amino acids than normal cells, leading to a build-up of Axumin inside prostate cancer cells. Because the compound contains a radioactive molecule, doctors can use a PET scan to detect areas of Axumin accumulation.