A Quantitative Evaluation of Joint Activity and Attenuation Reconstruction in TOF PET/MR Brain Imaging

• DOI: 10.2967/jnumed.118.220871
• Publication Date: 2019-04-12T22:45:19Z
• Authors: Ahmadreza Rezaei; Georg Schramm; Stefanie M.A. Wil...; Gaspar Delso; Koen Van Laere; Johan Nuyts
• Keywords: Correction for attenuation

Time-of-flight (TOF) PET data provide an effective means for attenuation correction (AC) when no (or incomplete or inaccurate) information is available. Since MR scanners little on photon of different tissue types, AC in hybrid PET/MR has always been challenging. In this contribution, we aim at validating the activity reconstructions maximum-likelihood ordered-subsets and (OSAA) reconstruction algorithm a patient brain set. We present quantitative comparison joint with current clinical gold standard—ordered-subsets expectation maximization—using CT-based PET/CT, as well state art PET/MR, that is, zero time echo (ZTE)–based AC. <b>Methods:</b> The TOF emission were initially used preprocessing stage to estimate crystal maps efficiencies, timing offsets, resolutions. Applying these additional corrections during reconstructions, OSAA, ZTE-based, vendor-provided atlas-based techniques analyzed compared our initial study, expected scatter later ZTE-based OSAA estimates compute contribution reconstructions. all scaling single-scatter simulation was correction. results 86 segmented regions interest Hammers atlas. <b>Results:</b> Our analysis showed that, practice, tracer difference +0.5% (±2.1%) +0.1% (±2.3%) could be state-of-the-art methods, respectively, standard PET/CT. <b>Conclusion:</b> Joint estimation methods can solution challenging problem studies scanners. With accurate TOF-based (timing offsets resolutions) calibration, similar method regional errors are within few percentage points.