I178] EANM/EARL harmonization strategies in PET quantification: From daily practice to multicentre oncological studies

Abstract

Quantitative positron emission tomography (PET-) imaging is essential for staging and tracking subtle processes like pathophysiologic change and therapy response in oncological diseases. The accuracy of PET-quantification decisively depends on the correct system calibration involving all corrections that are implicitly necessary using the full ring PET Detector setting in 3D mode. Basically, these are scatter-, random-, attenuation-, dead-time corrections and detector normalization on a regular basis as a requirement for correct activity quantification, that is, for the true measurement of the activity concentration in a given lesion, focus, organ or phantom. Moreover, activity quantification with PET is influenced by noise and by the method of data analysis/image-reconstruction that determine the contrast recovery and resolution. These requirements and parameters need to be addressed, selected and assessed with particular scrutiny if PET systems are to be used for semi- or fully quantitative outcomes for monitoring disease progression and/or therapy response in patient care and research settings. This is of even more importance if data is pooled across imaging sites and/or advanced methods like invasive or non-invasive pharmacokinetic modeling become increasingly considered for a particular trial. Depending on the intended method of quantification, several metrics are derived from that concentration and/or its course over time in blood and tissue. This talk will focus on the EANM/EARL strategy to harmonize and standardize PET-quantification across centers and, thus, give an insight in practical aspects, outcomes and benefits of an independent regular assessment of the calibration and image quality of hybrid PET systems. Sites and systems that get EARL accredited considerably save time and efforts if it comes to setting up the site and the system for inclusion and PET imaging within a particular trial were quantitative hybrid PET is a major part in reaching the endpoints of the multicenter study. Despite being first and foremost intended for accreditation for research settings, the conduct, design and outcome of the EARL accreditation raises awareness of the centers excellence in the patient care scenario also.