Mock-up of the EXPLORER scanner

World's first whole-body PET scanner gains momentum with new partnerships

January 18, 2017
By Lauren Dubinsky and Gus Iversen

A team of researchers known as the EXPLORER consortium is inking deals bringing it closer to achieving a lofty goal: producing the world's first whole-body (or total-body) PET scanner.

After conducting what was described as "an extensive review," the UC Davis-based team selected UIH America — a North American subsidiary of Shanghai United Imaging Healthcare — to build the first scanner prototype, which is slated for completion in mid-2018.

To design the scanner's detectors, the consortium has enlisted Cork, Ireland-based SensL Technologies.

Unlike conventional PET detectors that use vacuum-based photomultiplier tubes, the whole-body scanner will incorporate solid-state silicon photomultiplier light sensors, a choice that Bryan Campbell, CEO of SensL, believes will provide better resolution for a system of this size.

The EXPLORER scanner will have more than 560,000 detector elements and will be capable of simultaneously capturing all organs. It will also offer a 40-fold increase in effective signal compared to conventional PET technology.

Since the new scanner will provide greater sensitivity, the researchers anticipate that the radiotracers will last longer and the doses can be reduced.

“Early clinical applications will likely be in improved cancer diagnosis and monitoring, but this scanner will also be used for a host of research aimed at developing new diagnostic applications in areas such as inflammatory disease, metabolic disorders, diseases associated with multiple organ systems such as the brain-gut axis, and infectious disease just to name a few,” Dr. Simon Cherry, professor of biomedical engineering at UC Davis and a member of the consortium, told HCB News.

At the World Molecular Imaging Congress conference in September, Cherry said that the EXPLORER scanner will be able to do all of this work in a fraction of the time. It usually takes about 10 minutes to conduct a total body PET scan, but this scanner can cut that down to 15 to 30 seconds.

The EXPLORER consortium — which was formed in 2011 and also includes research groups at the University of Pennsylvania and the Lawrence Berkeley National Laboratory — has had to overcome its fair share of obstacles to reach this point in its project.

The first big challenge they faced was persuading the academic community that despite the high cost of the technology and the unproven benefit, it was worthwhile to develop the system. A PET/CT scanner already costs about $2 million and the whole-body PET scanner will be significantly pricier than that.

Fortunately, the research underway is supported by a five-year, $15.5 million grant by the NIH High-Risk, High Reward Program — one of eight given in the NIH’s transformative research category in 2015.

The team has also faced engineering challenges related to the large number of detectors and channels of electronics, physical size, power consumption, cooling and large amounts of data that the system generates. According to Cherry, those challenges are being resolved and a small-scale prototype for testing all the components will be complete before summer.

Using components donated by Siemens Healthineers, the EXPLORER consortium has already built a small-scale version of the system for primate whole-body imaging.

"We believe we have gathered leaders in the medical imaging field to quickly and cost-effectively bring this technology to reality in an exciting and innovative way," said Ramsey Badawi, professor of radiology at UC Davis and co-leader of the project, in reference to the just-announced partnerships.

Even after the logistical aspect of development is complete, Cherry and his team will still need to define and develop applications for the scanner that will impact patients’ lives. Everything from easing patient claustrophobia, to providing easy access for maintenance and replacement parts, to figuring out exactly how this powerful imaging system is going to help physicians better understand and treat disease.

“Developing the radiotracers, quantitative imaging tools and protocols to exploit the capabilities of this advanced technology will be the most exciting part, which will commence once the full-size scanner is built,” said Cherry. “We already have a long list of studies planned!”