Performance Measurements Standards Revisions Published for PET

The new standards are more accurate at measuring scatter fraction and random coincidences than previous versions.

The U.S. National Electrical Manufacturers Association (NEMA; Rosslyn, VA, USA) recently published the revisions, called NEMA NU 2-2007 Performance Measurements of Positron Emission Tomographs. The major change since the last edition addresses an improvement in the inclusion of cameras with intrinsically radioactive components. Affected tests include count losses and randoms, as well as sensitivity. The spatial resolution measurement has been expanded to include the measurement and reporting of source position. Also, appendix A has been deleted.

According to Michael E. Casey, Ph.D., a member of the Coincidence Imaging Task Force chartered by the Nuclear Standards and Regulatory Committee, NEMA NU 2-2007 specifies methods that can be performed on all currently available PET scanners. "These include single and multiple slice, discrete and continuous detector, and time-of-flight instruments, as well as multi-planar and volume reconstruction models, dedicated PETs, and other coincidence-capable imaging systems. Wherever possible, future developments that could be readily anticipated were taken into account.”

The committee has not specified methods that may be especially appropriate for evaluating time-of-flight instruments, pending further evaluation of those instruments by the clinical and scientific communities. Dr. Casey reported that while this standard provides several advantages, it is the patient who gains the most. "A person undergoing a study benefits when a hospital or physician is able to compare tomographs from different manufactures to determine which best meets the needs of the patient,” he said.

When the first standard was developed in the early 1990s, PET was a research modality that focused chiefly on the brain. During the 1990s, the focus shifted to clinical applications with the discovery that PET was an excellent tool for imaging cancer. The revised NEMA NU 2-2007 follows this trend and takes these applications into account. The focus of the standard has changed to highlight whole-body imaging.

The contents and scope of NEMA NU 2-2007 Performance Measurements of Positron Emission Tomographs may be viewed, by visiting NEMA's website.

NEMA is an association geared for the electrical manufacturing industry.


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