The quest for quantitative PET

PET imaging, for all its promise, is plagued by a few shortcomings. Molecular imaging’s superstar has not yet realized its potential in terms of quantification of patients’ response to treatment. Nor have providers universally delivered optimal reports to clinicians. Both are barriers to further dissemination and both may be on the verge of change.

PET performance and interpretation is prone to variation, which makes it difficult to compare datasets. The PET Response Criteria in Solid Tumors (PERCIST), which provide a framework for standard acquisition and measurement of patient response, address the issue.

“F-18 FDG PET/CT examination is today recommended for preoperative staging and detection of recurrence, and there is growing research attention to expanding the use of F-18 FDG PET/CT in evaluating the response of metastatic disease,” wrote Kristin Skougaard, MD, from the department of oncology at Copenhagen University Hospital Herlev in Herlev, Denmark, and colleagues in a review published in the April issue of The Journal of Nuclear Medicine.

“To create the reproducibility that is needed for comparison of response rates between trials, the use of F-18 FDG PET/CT in the setting of metastatic disease requires a fundamental standardization and consensus on response quantification methodology. Otherwise, the potential benefit for patients and for anticancer drug development could be lost,” the researchers continued.

Skougaard and colleagues compared PERCIST with the European Organization for Research and Treatment of Cancer (EORTC) criteria for quantifying response to anticancer treatment using PET/CT and reported PERCIST may provide a clearer protocol conducive for widespread adoption.

In a comprehensive review published in the May issue of The Journal of Nuclear Medicine, Ryan D. Niederkohr, MD, senior physician at Kaiser Permanente Medical Center in Santa Clara, Calif., and colleagues, urged nuclear medicine physicians to rethink how they handle PET/CT reporting.

The authors noted that essential information—study indication, time of tracer injection, patient treatment history and comparative detail regarding past imaging studies—was missing from more than 40 percent of reports.

Niederkohr et al offered a detailed protocol for creating optimal reports in the review.

How is your practice improving PET acquisition and reporting? Please let us know.

Lisa Fratt, editor