TY - JOUR T1 - Use of Activity Concentration Rate of Change Images to Enhance PET/CT Image Analysis JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1715 LP - 1715 VL - 59 IS - supplement 1 AU - Dustin Osborne AU - Shelley Acuff Y1 - 2018/05/01 UR - http://jnm.snmjournals.org/content/59/supplement_1/1715.abstract N2 - 1715Introduction: The standard uptake value (SUV) has been the standard clinical representation of PET data since the early days of the technology. This value provides a relatively simplified metric for assessing overall uptake, however, the fact that SUV is typically determined from a static snapshot of the PET tracer uptake limits its ability to stratify certain physiological characteristics. For example, a site of infiltration usually appears on a static SUV image as a bright area of uptake, when in fact, the area was slowly decreasing in activity throughout the uptake and imaging times. In this work we examine the use of whole-body continuous bed motion to create parametric maps of activity concentration rates of change (slope images) for the purpose of enhancing static SUV assessments and to provide additional information about the underlying rates of uptake that are not readily apparent in static images. Materials & Methods: Six patients were recruited under the auspices of a University of Tennessee Graduate School of Medicine IRB approved protocol. Patients were imaged at 45 minutes post-injection using a multi-pass whole-body continuous bed motion acquisition with 6 passes in approximately 15 minutes. Each pass was reconstructed into individual image volumes and compiled into a single dynamic image volume consisting of 6 time points with voxel data indicating activity concentration. Slope images were created by taking each voxel from the 6 time point volumes and calculating the slope in that voxel using the standard multi-point slope methodology: N∑XY−∑X∑Y/N∑X2−(∑X)2. Slope volumes were then compared to standard static FDG PET images. Results: Use of slope images complement standard FDG PET imaging. Slope images appear to assist in reducing the visual confusion of negative slope areas, such as areas of infiltration and regions involved with typical biological excretion. Sites of infiltration that show as bright areas on standard imaging are clearly visible as dark regions indicating decreasing activity concentrations over time (Figure 1). Visualization of rates of change also provide highlighting of areas within regions of uptake that are particularly increased compared to other areas in the volume. This may be important in radiation oncology where delineation of inhomogenous tumor areas can be critical to successful radiation therapy planning. Conclusions: Use of activity concentration slope images may provide useful and complementary information to standard static FDG PET imaging. ER -