PET phantom program expands to CV, brain
A prototype clinical PET oncology imaging simulator--or phantom--has been successfully scanned and imaged at four imaging centers, as part of the SNM Clinical Trials Network. The Society of Nuclear Medicine (SNM) said it is also testing a cardiac phantom and plans to develop a brain phantom prototype.

The society plans to deliver and scan the oncology phantom at an additional 20 imaging centers by the end of September.

The Clinical Trials Network evaluates images produced by phantoms to ensure that molecular imaging centers are providing consistent and accurate images. Phantom studies are helpful to determine image quality from a user perspective, as well as from a technology perspective. Imaging consistency among sites is critical for ensuring quality imaging and quantitative data and is essential to meet FDA requirements for investigational clinical trials, according to SNM.

"The community agrees that a lack of uniformity across imaging sites is a primary barrier to using imaging in clinical trials to facilitate drug development," said Michael Graham, PhD, MD, co-chair of SNM's Clinical Trials Network and director of nuclear medicine at the University of Iowa Carver College of Medicine. "When pharmaceutical companies apply to FDA for approval of a new product, they must first demonstrate a certain level of disease detectability as evidenced by some imaging measurement. Many of the denials of new drugs are based on a rejection of data compiled from poor-quality images or images that don't appear to match those from another similar study."

Imaging of the PET phantoms, which contain a known quantity and distribution of radioactivity, will be used to evaluate each site's imaging capabilities both qualitatively and quantitatively and ensure standardization and compliance with defined protocols in order to ensure consistency across multiple centers in a single trial.

The first phantom in use is the oncology phantom, which was scanned at each of four test sites--the University of Utah, University of Iowa, University of Pennsylvania and Mayo Clinic--using a standard imaging protocol. To test the resolution of the imaging equipment at each site, the phantom contained multiple simulated tumors of different sizes. Physicians at each of the four sites were able to evaluate the images and identify all the tumors.

Based on the initial success with the oncology phantom, the network is expanding its phantom imaging program by providing other phantoms to qualified sites in the network's registry. In this regard, a cardiac phantom is beginning testing at the four initial sites, and a brain phantom prototype is being developed and is anticipated to be available by June to assist a pharmaceutical company with site imaging evaluation for an upcoming phase 3 clinical trial.