Initial Results of a Prototype AWSM-PET Device for Augmented Whole-body PET Imaging

The Augmented Whole-body Scanning via Magnifying PET (AWSM-PET) is a technology designed to enhance the diagnostic accuracy of whole-body (WB) PET/CT imaging for the detection of small lesions. We recently constructed the first prototype AWSM-PET device that consists of two panels of high-resolution time-of-flight (TOF) PET detectors (using ~1mm pitched LSO crystals), integrated with the standard readout electronics and event processing architecture of the Siemens Biograph Vision scanner. The system exhibits excellent spatial, energy and timing resolution, with an average coincidence resolving time of ~183 ps FWHM and an average energy resolution of ~11% FWHM at 511 keV. Custom firmware and software have been developed to encode the large number of detector elements and to enable coincidence detection between the AWSM-PET detectors and the Biograph Vision scanner.Initial tests of the AWSM-PET device show the image resolution of the Biograph Vision scanner is improved from the original >3mm to ~2mm FWHM. A GPU-based list-mode image reconstruction framework has been expanded to incorporate the point-spread function (PSF) of the native scanner and the AWSM-PET detectors to optimize the spatial resolution and improve image quality.Standard step-and-shoot and continuous-bed motion imaging protocols are supported for the AWSM-PET operation and are being evaluated for the reconstructed image resolution and the uniformity of the overall system sensitivity across a long axial FOV. Extensive phantom imaging studies are ongoing to evaluate the system's performance. Initial human imaging studies will be presented in the upcoming 2023 Medical Imaging Conference.