By Efe Onodjae

A Nigerian nuclear physicist, Dr. Samuel Ajayi, has cautioned against the unsafe handling and disposal of Lutetium-177, a radioactive isotope increasingly used in the treatment of prostate cancer and neuroendocrine tumours, warning that improper management could pose long-term radiation and environmental risks.

Delivering a presentation titled “How Nuclear Structure Affects the Use and Handling of Lutetium-177,” during the fall meeting of the Florida chapter of Health Physics Society, Ajayi explained that while the radionuclide has proven effective for both therapeutic and diagnostic purposes, its nuclear structure presents long-term challenges for waste management and radiation monitoring.

According to him, Lutetium-177 emits beta particles that destroy cancer cells and low-energy gamma rays that allow doctors to track the treatment process through imaging. However, the radionuclide also contains a meta-stable state (Lu-177m) that remains radioactive for an extended period.

“The ground state of Lutetium-177 decays in about 6.6 days, but the meta state has a half-life of 160.4 days,” he said. “This means that unused Lu-177 remains active for years, posing additional storage and safety concerns.”

Dr. Ajayi, who based his findings on recent nuclear structure studies, warned that such prolonged activity could complicate hospital waste management systems. He noted that international regulations typically allow radionuclides with half-lives shorter than 120 days to decay in storage before disposal, making Lu-177m particularly problematic.

He further explained that the 414 keV gamma rays emitted by Lu-177m are similar to those released by plutonium-239, a key component of nuclear weapons, which can trigger false radiation alarms during screening.

“Because of these similar signatures, radiation detectors might mistake treated patients or medical waste for dangerous nuclear materials,” he added.

Dr. Ajayi also highlighted the need for careful consideration in the production process of Lutetium-177, noting that the method used, either direct or indirect nuclear reaction, determines the isotope’s purity and the level of contamination from the meta-stable state.

While acknowledging the growing success of Lutetium-177 in targeted radiotherapy, he called for stronger interdisciplinary collaboration between nuclear scientists and medical practitioners to enhance safety standards and improve monitoring procedures.

“We must ensure that the medical benefits of this radionuclide are not undermined by lapses in handling, regulation, or waste control,” he said.
Dr. Ajayi’s presentation also referenced the 2023 Long-Range Plan for Nuclear Science, which seeks to address how atomic nuclei behave and how nuclear processes can be applied safely in medicine, energy, and other critical sectors.

He urged government agencies, hospital administrators, and regulatory bodies to adopt stricter protocols for the transport, use, and disposal of radiopharmaceutical materials to protect both medical workers and the public.