First Total-Body PET Scanner Planned for 2017

The development of world's first total-body positron emission tomography (PET) scanner could change the way cancer and other diseases are diagnosed and treated.

The project, called Explorer, will design and build a PET scanner that images the entire human body simultaneously. To do so, a consortium between the University of California, Davis (UCD; USA), Lawrence Berkeley National Laboratory (LBL; Berkeley, CA, USA), and the University of Pennsylvania (Philadelphia, PA, USA) was formed with the goal of combining the strengths of each contributor to build a scanner that could reduce radiation doses by a factor of 40, and decrease scanning time from 20 minutes today to just 30 seconds.

The LBL contribution is to develop the electronics that will send the data collected by the scanner's detectors to a computer, which will convert it into a three-dimensional (3D) image of the patient. Since the new PET scanner will have half a million such detectors, the task is incredibly complex. UCD will develop a new molecular imaging agent and human-grade radio-labeled peptides for the project, as well as plans and computer simulations for the total-body scanner.

The University of Pennsylvania team, led by Prof. Joel Karp, PhD, will investigate and improve time-of-flight (TOF) PET imaging, and the quality of the reconstructed images, as well as aid in the clinical interpretation of disease. To do so, each major factor affecting system performance, such as the scintillation detector, the calibrations and processing electronics, data correction techniques, and the image reconstruction algorithm, will be studied independently to develop methodologies that are predictive of human ability to identify and quantify activity uptake in lesions.

“We're developing the electronic interface between the detectors and the computer algorithm—and the electronics for this scanner is an order of magnitude more complicated than what's been done before,” said LBL project leader William Moses, PhD, of the molecular biophysics and integrated bioimaging division. “But Berkeley Lab has a long history developing instrumentation for nuclear medical imaging, including PET scanners, and this project is another milestone in our research.”

“The vision of the Explorer project is to solve two fundamental limitations of PET as it is currently practiced. The first is to allow us to see the entire body all at once,” said UC Davis project leader professor of biomedical engineering Simon Cherry, PhD. “The second huge advantage is that we’re collecting almost all of the available signal, which means we can acquire the images much faster or at a much lower radiation dose. That’s going to have some profound implications for how we use PET scanning in medicine and medical science.”

PET scans are widely used to diagnose and track a variety of diseases, including cancer, because they show how organs function in the body, in contrast to MRI or CT scans, which mostly show anatomy. Using radioactive tracers that produce a signal from within the body, PET scanners produce a 3D image that is constructed by computers using sophisticated mathematical techniques. The Explorer project will address shortcomings of the current scanning technology, which requires more time and exposes the patient to more radiation because scans are done in 20 cm segments.

Related Links:
University of California Davis
Lawrence Berkeley National Laboratory
University of Pennsylvania