Physical Performance of Synchropet ArterialPET^TM, a Human Wrist PET Prototype Scanner for Noninvasive Arterial Input Function Evaluation

Arterial blood sampling (ABS) is considered the gold-standard method for evaluating the arterial input function in dynamic PET studies. However, ABS is invasive and associated with a high complexity and risks. Alternatively, image-derived input function (IDIF) methods can be employed to simplify protocols and enhance adoption of dynamic PET in research and clinical practice. However IDIF methods require scanning for longer periods at the scanner bed, can be limited by the short axial field-of-view (FOV) of the vast majority of modern clinical PET systems and are susceptible to noise and partial volume effects due to the large ring diameter and large detector elements size of modern clinical PET systems. In this work we are evaluating the physical performance of the SynchroPET ArterialPET^TM scanner (Stony Brook, NY, USA), a human wrist standalone cylindrical PET prototype system of 9 cm diameter ring and 1.73 cm axial FOV, capable of 4D PET imaging of the human wrist to enhance existing IDIF methods. The NEMA NU4-2008 performance evaluation protocol was selected to assess spatial resolution. system sensitivity and image quality. All PET data were acquired in list-mode, later sorted into 3D sinograms and reconstructed with an open-source 3D-OSEM algorithm with all data corrections included (decay, randoms, normalization, attenuation and scatter) when applicable. The average of radial and transaxial resolution was 1.49mm and 2.78mm FWHM at 5mm and 25mm radial distance from the center, respectively, while the respective axial resolution was 2.84mm and 4.69mm FWHM. The system sensitivity was 3.54 kcps/MBq. In terms of image quality, all hot rod sources were distinguishable with recovery coefficients of 21.71% and 96.21% for the 1mm and 5mm rod sources, respectively. ArterialPET can be utilized to extract IDIF data from human arteries in the wrist where a 2-5mm diameter is expected. Further clinical studies are needed to assess potential enhancement of IDIF methods.