Combined PET, X-ray CT offers ability to scan body in 3-D

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A medical imaging scanner that combines positron emission tomography and X-ray computed tomography is able to capture a 3-D image of the human body.

The combined technology has produced images far more quickly than currently used technology, according to those developing it at UC Davis.

Called Explorer, the machine captures radiation far more efficiently than other scanners, producing an image in as little as one second. In addition, over time, it can be used to produce movies that can track specially tagged drugs as they move around the entire body.

Developers say the technology has the potential to be used in countless applications, ranging from improving diagnostics, to tracking disease progression, to researching new drug therapies. The scanner has been developed in partnership with Shanghai-based United Imaging Healthcare, which built the system based on its latest technology platform; executives from the company say they eventually will manufacture the devices for the broader healthcare market.

The first images from scans of humans using the new device will be shown at the annual meeting of the Radiological Society of North America, running from November 25 to 30 in Chicago.

The total-body scanner was first conceptualized 13 years ago by UC Davis scientists Simon Cherry and Ramsey Badawi. Their idea was aided in 2011 with a $1.5 million grant from the National Cancer Institute, which enabled them to establish a wide-ranging consortium of researchers and other collaborators. It also got support in 2015 through a $15.5 million grant from the National Institutes of Health—that funding enabled them to team up with a commercial partner and get the first scanner built.

“While I had imagined what the images would look like for years, nothing prepared me for the incredible detail we could see on that first scan,” said Cherry, distinguished professor in the UC Davis Department of Biomedical Engineering.

Cherry said he was dumbfounded when he saw the first images, which were acquired in collaboration with UIH and the Department of Nuclear Medicine at the Zhongshan Hospital in Shanghai.

“The level of detail was astonishing, especially once we got the reconstruction method a bit more optimized,” says Badawi, chief of Nuclear Medicine at UC Davis Health and vice chair for research in the Department of Radiology. “We could see features that you just don’t see on regular PET scans. And the dynamic sequence showing the radiotracer moving around the body in three dimensions over time was mind-blowing.”

Cherry said he expects Explorer will have a profound impact on clinical research and patient care because it produces higher quality diagnostic PET scans than have ever been possible. The technology also scans as much as 40 times faster than current PET scans and can produce a diagnostic scan of the whole body in as little as 20 to 30 seconds.

Alternatively, Explorer can scan with a radiation dose that’s 40 times less than a current PET scan, opening new avenues of research and making it feasible to conduct many repeated studies in an individual, or dramatically reduce the dose in pediatric studies, where controlling cumulative radiation dose is particularly important.

For the first time, an imaging scanner will be able to evaluate what is happening in all the organs and tissues of the body simultaneously. For example, it could quantitatively measure blood flow or how the body takes up glucose everywhere in the body. Researchers envision using the scanner to study cancer that has spread beyond a single tumor site, inflammation, infection, immunological or metabolic disorders and many other diseases.

UC Davis is working closely with UIH to get the first system delivered and installed in Sacramento, and the researchers hope to begin projects and imaging patients using the technology as soon as next June.

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