The detectors are composed of a Cerenkov radiator, which efficiently absorbs gamma rays and very quickly emits a small number of photons of visible light. An attached microchannel plate photomultiplier tube (MCP-PMT) converts the photons into electrons and increases the number of electrons into a detectable signal that providers can measure. The signal has a timing precision of about 25 picoseconds. Combining the MCP-PMT and Cerenkov radiator allows users to calculate the arrival time of the gamma rays within about 30 nanoseconds, according to Cherry.

Sun II Kwon, a project scientist in the UC Davis department of biomedical engineering, and Ryosuke Ota at Hamamatsu Photonics, performed experimental work with the technique in a variety of tests, including one that used an object to mimic the human brain. Cherry and his colleagues believe that with further development, the approach can be scaled to a level where it can be applied in clinical diagnostics to potentially create higher-quality images at lower radiation doses.


“The ultimate goal would be to have a scanner with the uEXPLORER geometry, but with these ultra-fast detectors,” said Cherry. “That would be an amazing diagnostic imaging device. Just as uEXPLORER was a step change over conventional scanners, this would be another step change over uEXPLORER. But, there is a long way to go before we can scale up from the two detectors in our paper, to the 500,000+ detectors in uEXPLORER.”

He adds that there will be several key developments and innovations including miniaturizing components, developing multichannel devices, developing electronics that can operate at this speed and be scalable and for the development to be cost-effective to use in a diagnostic device. Significant technology improvements are needed before the approach can be used on humans. The researchers hope to begin applying it in small animal imaging in the next two to three years.

Other collaborators included research groups led by professor Yoichi Tamagawa at the University of Fukui, and by professor Tomoyuki Hasegawa at Kitasato University.

The findings were published in Nature Photonics.

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