TY - JOUR T1 - Is <sup>90</sup>Y-PET feasible with systemic injection? JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 205 LP - 205 VL - 52 IS - supplement 1 AU - Thomas Carlier AU - Ludovic Ferrer AU - Etienne Garin AU - Caroline Bodet-Milin AU - Caroline Rousseau AU - Catherine Ansquer AU - Frederic Schoenahl AU - Sophie Laffont AU - Francoise Kraeber-Bodere Y1 - 2011/05/01 UR - http://jnm.snmjournals.org/content/52/supplement_1/205.abstract N2 - 205 Objectives Since the theoretical prediction of the 0+-0+ transition of 90Zr, 90Y-PET has recently renewed interest with the development of radioembolization (RE) of liver tumors (LT). The aim of this study is threefold: 1) determine the minimal detectable activity (MDA) to assess the feasibility of 90Y-PET imaging for systemic injection, 2) evaluate the impact on quantitation, 3) assess the benefit of using TOF information. Methods The study was conducted on the Siemens Biograph® mCT with the extended axial FOV and TOF options. An IEC phantom (IECp) was uniformly filled (200 kBq/mL) with a target-to-background ratio of 40:1. The IECp was imaged 8 times in 14 days over 30 min. Sinograms were reconstructed with OSEM with and without TOF information (from 1 to 6 iterations, 21 or 24 subsets, voxel size: 4 ×4×2 mm3, 2 mm FWHM 3D gaussian post-smoothing). The contrast-to-noise ratio (CNR) was computed based on the Rose criterion accounting for partial volume effects. The impact of TOF and OSEM iterations on quantitation and detectability were investigated. Finally, 4 patients with LT and 4 patients included in different 90Y-based radioimmunotherapy protocols were enrolled. Results The higher detectability was reached with 1 iteration for both TOF and non-TOF reconstruction (nTOF). The MDA was lower for TOF in comparison with nTOF. There was no gain to use TOF in terms of detectability for concentration higher than 2 MBq/mL except for infracentimetric lesions. The use of a single iteration or nTOF was at the expense of recovered activity which can be severe (10-150% less depending on the lesion size). Reconstructed volumes from patients with a RE were interpretable, unlike those of patients who received systemic injections of 90Y. Conclusions If accurate localization of the lesions is preferred, only 1 iteration and TOF are necessary with a MDA of 0.8 MBq/mL. When quantitation is needed, an acceptable recovered activity is reached with 3 iterations, TOF and a MDA of 1 MBq/mL ER -