I122] Quantitative molecular imaging: Can we trust the SUV?

Abstract

Metabolic activity can be measured using FDG PET/CT. Quantification of FDG PET/CT studies is often based on so-called standardised uptake values (SUV). SUVs or other metabolic parameters, such as metabolic volume and total lesion glycolysis can be used for metabolic phenotyping of the tumor. These quantitative metrics are affected by various sources of bias [1] . Factor influencing tracer uptake can be described as technical, imaging physics related or biological uncertainties. Effects of the above mentioned factors on SUV should be mitigated and/or harmonized as much as possible [2] . Harmonization of PET/CT examinations aims at making SUV reads as exchangeable (comparable) and reproducible as possible by harmonizing imaging procedures, image quality and quantitation and harmonizing data analysis methods and interpretation. The main challenge of harmonisation arises from differences in PET/CT imaging procedures and in technology across multiple sites and users. To this end the European Association of Nuclear Medicine published FDG PET/CT imaging guidelines [2] and started a multicentre accreditation program. Moreover, continuous monitoring of the FDG PET/CT data quality is warranted [3] . In this lecture the principles of metabolic imaging with PET, the mechanism of FDG uptake, various factors affecting FDG PET/CT tracer uptake and its quantification by SUV will be discussed. Moreover, the need for validation of simplified uptake metrics, such as SUV, against full kinetic analysis and use of FDG PET as quantitative metabolic imaging biomarker will be addressed. Finally, it will be shown that by standardisation of imaging procedures and by ongoing quality control of the PET/CT systems, FDG uptake can be reliably quantified.