Steven Meikle (M’96-SM-‘00) is Professor of Medical Imaging Physics at the University of Sydney, Head of the Imaging Physics Laboratory at the Brain and Mind Centre (BMC) and Deputy Director of Sydney Imaging Core Research Facility. He received his Ph.D. from the Graduate School of Biomedical Engineering, University of New South Wales in 1995. He was a medical physicist at Royal Prince Alfred Hospital in Sydney from 1987-2004, a visiting research associate at the Division of Nuclear Medicine and Biophysics, UCLA School of Medicine from 1991-2 and a postdoctoral research scientist at the MRC Cyclotron Unit in London from 1995-6, before joining the University of Sydney in 2004. He is best known for his contributions to the development of quantitative PET and SPECT methodology and technology for imaging awake small animals. He has published more than 200 research papers which have attracted over 7,000 citations (h-index 45). He is currently the Nominations Chair and Past President of the Nuclear and Plasma Sciences Society (NPSS). He served as Vice President (2019-20) and President (2021-22) of NPSS and as the NMISC elected representative on AdCom (2015-18). He is a Senior Member of the IEEE, Fellow of the Australian Institute of Physics and Fellow of the Australian Society of Molecular Imaging.
Abstract Prof. Meikle Lectures:
Introduction to Kinetic Modelling: When we introduce a radio-labelled biomolecule (i.e. a radiopharmaceutical) into the human body, it is subject to the same physiological and biological processes as the unlabelled molecule would have undergone had it been administered instead. This is called the tracer principle and, provided it meets certain criteria, we can consider the radiopharmaceutical to be a “tracer” for its unlabelled counterpart. The processes that determine the concentration of the tracer in tissue and blood at any point in time include regional blood flow, extraction from the blood into the interstitial space, cellular (surface or intracellular) uptake and clearance, and metabolism. The cellular components of uptake and clearance are controlled by enzymatic activity and/or cell surface receptors. For many diagnostic applications of nuclear medicine we don’t need to measure each of these processes or indeed any of them. We simply wait a pre-determined time following tracer administration when we expect the target to background ratio of the tracer to be sufficiently high, take a static image and quantify the regional uptake (e.g. standardized uptake value, SUV) in the target region(s). However, sometimes it is very useful to quantify these physiological parameters. For this we require kinetic models and, depending on the model and tracer, we also often require dynamic scanning. In this lecture we will discuss the foundational principles of tracer kinetic modelling, some typical models for various PET tracers and their underlying assumptions, and the most common methods used to estimate the model parameters. We will also discuss some of the more common clinical and research applications of tracer kinetic modelling.
