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. umol 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 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.