SU‐FF‐I‐148: Performance Comparison of An In‐House and a Commercially Available Amplitude Gating Device for PET Imaging

Abstract

Objective: To compare the performance characteristics of an in‐house amplitude gating device to the Anzai respiratory gating system in PET imaging. Methods: A MLT‐1132 respiration transducer was coupled to a cDAQ‐9172 data‐acquisition device to digitize the respiratory signal. A Labview® program was designed to inject triggers into PET List streams whenever the respiration amplitude crossed the edges of a user‐set amplitude‐range (gate) and stop the scan when the accumulated gated scan‐duration reached a user‐set interval. To test its performance, a phantom containing one stationary (33mm) and 2 moving spheres (33&17mm) was imaged in 3D mode on a GE‐DRX PET/CT scanner (SBR=5.1). The two moving spheres were attached to a moving platform (2cm‐pp‐sinusoid, 5sec‐cycle) while the MLT‐1132 and Anzai transducers were secured to the platform simultaneously. Respiration signals from the two transducers were synchronized using triggers from the Anzai device. The gated amplitude‐range and scan‐duration were 80–100% of the motion amplitude and 3min respectively which resulted in 10min of total scan‐duration. The List data was first filtered by only keeping data within the gate and then reconstructed (3D‐IR) to generate a MLT‐1132‐gated image. Furthermore, the same list data was retrospectively gated based on the Anzai respiratory signal and an Anzai‐gated image was also reconstructed. In addition, two ungated images (10&3min) were unlisted and reconstructed from the same list data. All images were compared using line profiles, contrast, max and mean activity concentration (AC) for all spheres. Results: The respiratory waveforms recorded by the two devices and their respective Fourier transforms were identical and had a correlation coefficient of 0.97 & 0.99 respectively. The two gated images showed similar contrast (<3% difference) and AC (<2% difference) and exhibited similar improvement in contrast & AC when compared to ungated images. Conclusion: Our in‐house amplitude‐gating device has similar performances compared to the Anzai equipment