EXPLORER, a UC Davis imaging breakthrough, makes a media splash

EXPLORER, a UC Davis imaging breakthrough, makes a media splash


EXPLORER, the world’s first total-body positron emission tomography (PET) scanner that can capture a 3D picture of the whole human body at once, is up and running at UC Davis Health.

Developed by UC Davis scientists, EXPLORER has already captured the attention of radiology experts around the world. It was featured in an article in Nature and its images have drawn hundreds of thousands of views on YouTube.The scanner and its inventors were introduced to local media outlets on Monday.

Image quality a game changer

EXPLORER’s exceptional image quality gives it nearly limitless potential applications for both clinical use and research.

“We are thrilled, after almost 15 years, to finally have brought this concept of total-body imaging to fruition,” said co-inventor Simon Cherry, distinguished professor in the UC Davis Department of Biomedical Engineering. “The first images coming off the EXPLORER scanner have exceeded what we, and I think many others in our field, thought would be possible.”

The EXPLORER scanner, which combines PET and x-ray computed tomography (CT), was installed in May in a specially prepared space on Folsom Boulevard. Built by UC Davis industry partner United Imaging Healthcare (UIH), EXPLORER was shipped in two 40-foot containers to a warehouse in Oakland. From there, the parts arrived by truck in several deliveries.

EXPLORER installation complete

Crews from both UC Davis and the U.S. team at UIH then assembled the scanner – at 11 tons, about the weight of a cruise ship anchor. The parts include a CT gantry (cylinder) and supporting base at more than 6,000 pounds, the PET scanner, with all the rings at 16,000 pounds, and the patient bed at 1,760 pounds.

In addition to the scanner, the space includes a liquid cooling system with insulated piping to keep the machine’s electronics cool night and day. A separate room is used to house the many computers required to run the gantries that contain the scanner’s radiation detectors and the unit that distributes the multi-voltage power supplies.

EXPLORER will scan its first research subjects in the U.S. in late June and will scan its first patients later this summer. The scanner has broad applications for cancer diagnosis, as well as for studies of blood flow, inflammation, immunological and metabolic disorders and infections. The developers also anticipate it will be useful for patients with brain diseases, heart conditions and diseases that involve multiple organs, as well as for children because of its speed and relative safety. 

“We are able to see things we have never seen before,” said co-inventor Ramsey Badawi, chief of Nuclear Medicine at UC Davis Health and vice-chair for research in the Department of Radiology. “I think we are going to be able to make a huge difference in both research and clinical medicine.”

What’s different about EXPLORER?

  • The quality of the images is much better, allowing physicians to see smaller tumors and other diseases earlier.
  • The scanner can be set up to run much faster than conventional PET scanners, which can make it easier and more comfortable for patients. This is particularly good for young children or patients with joint pain.
  • The scanner can alternatively be set up to use much less radiation, which is helpful for children, or research where the same person needs to be scanned many times.
  • The entire body can be imaged at the same time, which means it can track changes in a drug’s distribution throughout the entire body, enabling an understanding of concentration of medicine in every organ and tissue over time.

Badawi and Cherry first conceptualized a total-body scanner 14 years ago. Their idea was kick-started in 2011 with a $1.5 million grant from the National Cancer Institute, which allowed them to establish a wide-ranging consortium of researchers and other collaborators. The project got a giant boost in 2015 with a $15.5 million grant from the NIH.  

The scanner is now commercially available from United Imaging Healthcare, an advanced imaging development company based in Shanghai with subsidiaries throughout China, the U.S. and other parts of the world.