New Scatter Correction Strategies on HRRT Studies

Purpose: The aim of this study is to evaluate the impact of different scatter correction strategies on quantification of high-resolution research tomograph (HRRT) data for three tracers covering a wide range in kinetic profiles. Procedures: Healthy subjects received dynamic HRRT scans using either (R)-[C]verapamil (n=5), [C]raclopride (n=5) or [C]flumazenil (n=5). To reduce the effects of patient motion on scatter scaling factors, a margin in the attenuation correction factor (ACF) sinogram was applied prior to 2D or 3D single scatter simulation (SSS). Results: Some (R)-[C]verapamil studies showed prominent artefacts that disappeared with an ACF-margin of 10 mm or more. Use of 3D SSS for (R)-[C]verapamil showed a statistically significant increase in volume of distribution compared with 2D SSS (p<0.05), but not for [C]raclopride and [C]flumazenil studies (p>0.05). Conclusions: When there is a patient motion-induced mismatch between transmission and emission scans, applying an ACF-margin resulted in more reliable scatter scaling factors but did not change (and/or deteriorate) quantification.