Total-body PET: Maximizing sensitivity for clinical research and patient care

January 3, 2018, Society of Nuclear Medicine and Molecular Imaging
Photograph of the EXPLORER scanner (left) at UC Davis Medical Center and maximum intensity projection images of two frames from a mini-EXPLORER dynamic total-body imaging study following injection of 8.5 MBq 18F-FDG (1/10th standard activity) in a 4.6 kg rhesus macaque. Credit: Simon Cherry et al., University of California, Davis, Calif.

The new total-body PET/CT scanner could revolutionize our understanding and treatment of disease through analysis of better imaging data from the whole body. In The Journal of Nuclear Medicine (JNM) featured January article, scientists at the University of California, Davis (UC Davis), outline the development and benefits of this innovative diagnostic tool and explain how maximizing PET sensitivity will advance clinical research and patient care.

Positron emission tomography (PET) is widely considered the most sensitive technique available for non-invasively studying physiology, metabolism and molecular pathways in the living human being. However, there have been drawbacks, including low signal-to-noise ratio (SNR) affecting image quality, long imaging times and concerns regarding .

Total-body PET, which encompasses the entire body within the field of view and allows imaging of all the tissues and organs of the body simultaneously, promises to be a game changer.

"It will offer the ability to detect throughout the whole body the location of focal pathologies, including cancer, infection, and inflammation at considerably lower levels of disease activity than is currently possible," explains Terry Jones, DSc, clinical professor of diagnostic radiology at UC Davis.

He points out, "It will also reduce the time taken to scan the whole body by at least a factor of 10, leading to scan times that could be less than one minute. This, for example, will make it far easier to scan infant and pediatric subjects without anesthesia or sedation."

Radiation exposure is reduced as well. Jones notes, "Whole-body PET scans could be performed for a radiation dose roughly equivalent to that received from a round-trip transatlantic flight."

By covering the entire body at once, sensitivity is increased by a factor of ~40 for total-body imaging, or a factor of ~4-5 for imaging a single organ such as the brain or heart. Significant improvements in timing resolution could lead to even further sensitivity gains.

The JNM article states, "Total-body PET offers several opportunities to change the methodological approach to cancer detection and staging, and this same methodology could also be applied to other systemic conditions, including inflammation (e.g. sarcoidosis), vascular disease, sepsis and infectious disease. The increased sensitivity and dynamic range of total-body PET will allow imaging at high SNR at much later times after tracer injection."

Jones adds, "The ability to study the simultaneous interaction of specific molecular/physiological processes between all the tissues/organs of the body—'systems biology' of the human body in health and disease—is especially relevant for functional brain-body, and body-brain interactions that occur in certain psychological, psychiatric, neurological, and inflammatory conditions."

EXPLORER project co-leaders Simon Cherry, PhD, professor of biomedical engineering, and Ramsey Badawi, PhD, professor of radiology, at UC Davis, explain the potential benefits of total-body PET/CT. Credit: University of California, Davis

This new technology is nearing clinical readiness. UC Davis, in collaboration with United Imaging Healthcare, has completed the design of the first prototype total-body PET/CT scanner, called EXPLORER, and components are currently being fabricated and tested. The CT scan is acquired as the patient moves into the PET scanner. A smaller-scale, mini-EXPLORER is for researchers to conduct total-body PET imaging in nonhuman primates.

Total-body PET/CT was initially conceived for clinical research, and it will be a boon for researchers. For example, the ability to determine the pharmacokinetics of new drugs in all the organs and tissues of the body at very low masses and radiation doses has the potential to accelerate the translation of new therapeutic agents to clinical practice.

It has become clear, however, that the new scanner will also impact patient diagnosis and care. "The applications of nuclear medicine will expand considerably across internal medicine at a rate not witnessed to-date, and will become more evenly distributed across the age spectrum," says Jones. "There will be a considerable stimulus/investment to develop new imaging biomarkers especially within immunology and endocrinology."

He anticipates changes in nuclear medicine departments as well, stating, "One total-body PET scanner could take on the work load of three-to-four conventional PET scanners, and being able to receive imaging biomarkers from more distant distribution centers [due to the scanner's increased sensitivity, which gives biomarkers increased shelf life], will minimize the need for costly in-house biomarker production."

Addressing the cost issue, Jones also points out, "As the impact of high-sensitivity, total-body PET scanning becomes apparent, this will provide a major stimulus to physicists, chemists, and engineers to develop lower-cost detectors for total-body surveillance."

In short, Jones sees the development of total-body PET/CT as " coming of age."

Explore further: World's first total-body PET scanner takes a big step forward

More information: Simon R. Cherry et al, Total-Body PET: Maximizing Sensitivity to Create New Opportunities for Clinical Research and Patient Care, Journal of Nuclear Medicine (2017). DOI: 10.2967/jnumed.116.184028

Related Stories

World's first total-body PET scanner takes a big step forward

January 17, 2017
The UC Davis-based EXPLORER consortium, which aims to build a revolutionary total-body PET (positron emission tomography) scanner, has announced the selection of two industry partners to help build the prototype device. They ...

New PET-CT scan improves detection in rare cardiac condition

July 20, 2017
Using a new imaging technique that can diagnose cardiac sarcoidosis much more accurately than traditional tests, researchers from the University of Illinois at Chicago have found that the disease affects other organs in 40 ...

Promising new prostate cancer test developed

October 10, 2017
An easy to produce prostate cancer tracer, a substance vital for the discovery of cancers, has been developed by King's College London PhD student Jennifer Young.

Novel PET tracer identifies most bacterial infections

October 5, 2017
Stanford University medical scientists have developed a novel imaging agent that could be used to identify most bacterial infections. The study is the featured basic science article in The Journal of Nuclear Medicine's October ...

Recommended for you

Function of neutrophils during tumor progression unraveled

October 15, 2018
Researchers at The Wistar Institute have characterized the function of neutrophils, a type of white blood cells, during early stages of tumor progression, showing that they migrate from the bone marrow to distant sites and ...

Delving where few others have gone, leukemia researchers open new path

October 15, 2018
A Wilmot Cancer Institute study uncovers how a single gene could be at fault in acute myeloid leukemia (AML), one of the deadliest cancers. The breakthrough gives researchers renewed hope that a gene-targeted therapy could ...

3-D mammography detected 34% more breast cancers in screening

October 15, 2018
In traditional mammography screening, all breast tissue is captured in a single image. Breast tomosynthesis, on the other hand, is three-dimensional and works according to the same principle as what is known as tomography. ...

More clues revealed in link between normal breast changes and invasive breast cancer

October 15, 2018
A research team, led by investigators from Georgetown Lombardi Comprehensive Cancer Center, details how a natural and dramatic process—changes in mammary glands to accommodate breastfeeding—uses a molecular process believed ...

Cancer stem cells use 'normal' genes in abnormal ways

October 12, 2018
CDK1 is a "normal" protein—its presence drives cells through the cycle of replication. And MHC Class I molecules are "normal" as well—they present bits of proteins on the surfaces of cells for examination by the immune ...

Obesity linked to increased risk of early-onset colorectal cancer

October 12, 2018
Women who are overweight or obese have up to twice the risk of developing colorectal cancer before age 50 as women who have what is considered a normal body mass index (BMI), according to new research led by Washington University ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.