Quantification Tool Designed for Oncology Treatment Evaluation

In an effort to promote further the utility of positron emission tomography/computed tomography (PET/CT) imaging in assessing the effectiveness of oncology treatments, a new quantification tool to support PERCIST (PET response criteria in solid tumors) has been designed. The tool provides standard uptake value (SUV)-based metrics to define response criteria designed to complement the standard Response Evaluation Criteria in Solid Tumors (RECIST) criteria.

PERCIST was developed by Siemens Healthcare Molecular Imaging (Erlangen, Germany) and was presented in November 2010 at the American Society for Therapeutic Radiology and Oncology meeting in San Diego, CA, USA. Since the introduction of PERCIST, Siemens created a PET/CT quantification tool to aid in the adoption of PERCIST evaluation criteria. Using a consistent PET protocol, and fixed small region of interest, Siemens' quantification tool assesses the most active region of metabolically active tumor to minimize statistical variability and provide the most consistent results. Siemens supports industry initiatives with this software tool that will make PERCIST data available and reproducible for every patient so that these criteria will be clinically adopted and used in the field.

"Because Siemens believes in the power of molecular imaging, we have created a PERCIST quantification tool to support the adoption of PERCIST as standard of care,” said Britta Fuenfstueck, CEO, molecular imaging, Siemens Healthcare. "An industry-wide adoption of PERCIST criteria for oncology treatment evaluation will further prove the benefit of earlier and more precise detection using the predictive value of PET, and allow physicians to offer more targeted and individualized treatment for patients.”

RECIST is a well-established set of rules for determining response to therapy for patients. These criteria were formed on the basis of measuring anatomic changes in tumors using CT imaging. Because PET/CT imaging can detect changes to the tumor at the molecular level, thought leaders in the molecular imaging field introduced PERCIST criteria to use together with RECIST.

While RECIST criteria offer quantifiable data in terms of tumor size, the PERCIST quantification tool creates reproducible, objective results based on metabolic data for tumor trending over time to determine the effectiveness of treatment. PERCIST criteria allow treatment response to be measured in the absence of anatomic change through the assessment of metabolic activity; and frequently even before anatomic changes take place. The PERCIST quantification tool evaluates and delineates metabolic information from the tumor. The tool uses an algorithm that automatically identifies peak SUV within a volume of interest, instead of the common single pixel measure of SUVmax. The PERCIST quantification tool offers a stronger metric that is less susceptible to statistical variation and noise.

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