TY - JOUR T1 - Clinical evaluation of a prototype time-of-flight PET/CT system JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 1513 LP - 1513 VL - 50 IS - supplement 2 AU - Brad Kemp AU - Mark Nathan AU - Eric Rohren AU - Patrick Peller AU - Robert Murphy AU - Val Lowe Y1 - 2009/05/01 UR - http://jnm.snmjournals.org/content/50/supplement_2/1513.abstract N2 - 1513 Objectives A clinical evaluation of the image quality of 3D whole body PET/CT scans acquired on a GE prototype time-of-flight (TOF) PET/CT system was undertaken. Methods The study population included 40 patients with an average weight of 84.2 ± 13.3 kg and BMI of 27.4 ± 4.5 kg/cm2. Images of 3 and 5 min/bed duration were reconstructed using a fully-3D OSEM algorithm with and without timing information (TOF and nonTOF); otherwise the same reconstruction parameters were used for all images. Four blinded physicians rated noise, lung boundary resolution and overall image quality on scale from 0 (poor) to 3 (excellent). Also, the conspicuity of predetermined lesions was assessed by rating the uptake in the lesions with respect to uptake in the mediastinum. Finally, the relative image quality of the four image series for each patient were ranked on a scale from 1 (best) to 4 (worst). Results The mean physician ratings for 25 patient studies are shown in the table below. The rank order of these results is consistent across all BMI groups. The subjective evaluation shows an increase in noise in the liver with an increase in BMI for both TOF and nonTOF images, while resolution of the lung boundary is consistent across BMI groups only for TOF images. Lesion conspicuity shows a small yet insignificant increase in the apparent uptake for the TOF images, in those lesions with an uptake greater than or equal to the mediastinal blood pool for all locations of lesions. Conclusions Generally the TOF images possessed greater contrast and delineation of activity, at the expense of slight increase in noise, which can be attributed to different convergence rates for the TOF and nonTOF reconstructions. ER -