BETTER DETECTORS
Revolutionary Radiation Detection System Could Improve Medicine, National Security

Pinpointing cancer tumors in the human body is challenging, especially when the tumors are tiny or scattered. Locating the exact geographic site of a covert nuclear test is also difficult.

OSU health physics professors Abi Farsoni and David Hamby are working with a team of graduate students to develop a new digital radiation detector that could improve nuclear test ban compliance, cancer treatment, radioactive waste management, worker safety, and more.

Unlike other detectors, this one can simultaneously detect and measure both gamma and beta radiation, and uses digital technology and radiation spectroscopy in ways that enable identification of the source. Other detectors can measure either beta or gamma radiation, but they cannot distinguish the two and must be carefully calibrated and used in ways to compensate for interference or “crosstalk” from naturally occurring background radiation.

“This is more than detection,” Farsoni says. “We designed the detector, as well as the digital processor and the algorithms, so we can discriminate between radiation types.”

Measuring two types of radiation at the same time makes this detector very unique and very useful, he says. Other systems use bulky, analog systems that were developed in the 1960s or 70s.

The new system can also reject or eliminate background sources of radiation. “So we can detect ultra-low activity,” Farsoni adds.

Using the OSU developed detector system, the precise geographic location of covert nuclear tests could be pinpointed from hundreds of miles away based on the radiation found in Xenon gas, which is released during nuclear explosions and drifts in the atmosphere.

The detector technology could also be incorporated into surgical probes used by surgeons removing cancerous tumors. A patient is injected with a solution containing low-level radiopharmaceuticals so the probes can “see” the patterns of concentration, helping pinpoint tumors. Probes in use today, however, have difficulty separating background gamma radiation from the beta radiation on the tumor.

“Physicians want to detect only the radiation that has been injected,” says Hamby. “That is much more easily done with this new system.”

Current probes also have a slight delay, which makes pinpointing precise locations of very small tumors a challenge. The new digital detector generates real-time signals without any delay, and can be calibrated to “ignore” background radiation.

Much of the radiation detection technology in use today is quite outdated, Farsoni says. But with the recent resurgence of interest in nuclear power and a broader use of low-level radiation in medical applications, new tech­nology is under development and research funding is on the rise.

Farsoni and Hamby have received two grants to date totalling $1.6 million, supporting more than seven graduate students. The OSU researchers hope to take their invention from prototype stage to commercial product, and they believe the demand for such a system will be large.

Photo: OSU professors of health physics Abi Farsoni (right) and David Hamby work with electrical engineering graduate student Siavash Yousefi on a prototype of a groundbreaking nuclear radiation detector.