PET/CT and PET/MR quantitative imaging applications

Due to its unique physical decay properties, positron emission tomography (PET) was developed,
commercialized and marketed as a quantitative imaging technique. The first commercial scanners sold
in the 1970s targeted the clinical research market, in particular for neurology and cardiology
applications. The 1980s saw the rapid development of a new PET tracer called 18-F fludeoxyglucose
(FDG), which is an effective tracer to quantitatively measure absolute glucose metabolism (e.g. mol of
glucose/min/100 gm of tissue) non-invasively. It was soon shown that FDG PET filled an unmet clinical
need for both the diagnosis and treatment of cancer patients, and the 1990s saw a rapid growth of
clinical PET. PET FDG innovations in the 2000s included whole body PET scans (e.g. moving the
patient bed so patients can be scanned from head to toes), and the hybridization of PET scanners with
CT and MR for better anatomical location. Today, 95% of all clinical PET scans are whole body FDG
oncology scans. However, in order to make the scan time shorter and the analysis and reading faster,
surrogate measures of absolute glucose metabolism were developed. The most popular surrogate is the
standardized uptake value (SUV), and this talk will cover the pros and cons of using the SUV as a
quantitative measure and initiatives driven by PET physicists and clinicians to make it a better universal
and quantitative measure. The latest quantitative PET innovations from industry will also be presented,
including making the measure of absolute glucose metabolism practical in the clinic – effectively bringing
PET full circle and back to its commercial beginnings.