Simplified quantitative imaging techniques for analysis of dynamic PET/CT scans in response assessment: A promising approach for routine clinical use

Learning Objectives 1. To understand the limitations of current approaches in cancer therapy response assessment. 2. To be able to describe research PET scan procedures; their advantages; and the barriers to clinical implementation. 3. To understand the meaning of some of the commonly used parameters from an analysis of dynamic PET data. 4. To be able to describe simplifications to research procedures that can lead to clinically feasible extended PET protocols and to understand the effect of such simplifications on deduced physiologic parameters.

PET is a powerful clinical imaging modality in the initial staging of various malignancies and in the assessment of treatment response. In usual clinical practice, single time point imaging is performed without blood sampling yielding a global estimate of tracer uptake, usually expressed as SUV. Much additional data (e.g. dynamic acquisition and arterial blood sampling) can be obtained and analyzed to yield imaging rate-constant parameters reflective of the more complete physiological status of the tissue. Because of their complexity, burden on clinical resources, and tolerability by patients, such acquisitions and analyses are typically reserved for research applications. However, there is increasing interest in adding these quantitative biomarkers to the utility of clinical PET by adapting simplified (i.e. clinically feasible) versions of research procedures to yield an improved understanding of tumor response to therapy. Examples of simplifications include the use of image-based input curves (rather than from arterial blood sampling) and the use of abbreviated shortened dynamic acquisitions (Table shows proposed clinical scheduling of dynamic and standard PET-CT scans) allowing for routine clinical throughput.

Research Support Supported by NIH grant 1U01CA140230 to Dr. Mountz

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Proposed Shortened Clinically Feasible Acquisition times for dynamic PET-CT scans