Imaging Probe Development
The discovery of new imaging probes is critical to the advancement of disease diagnosis and therapy. Imaging probes allow non-invasive 3D molecular imaging of biochemical processes in living organisms. They consist of two components, one of which targets the biochemical process of interest, and the other which is an imaging component that allows for the external viewing of the probe location within the body. The probes can be small molecules, peptides, antibodies or nanoparticles that can be tailored for various imaging technologies i.e. MRI, CT, optical and nuclear (PET, SPECT).
Novel imaging probes are being developed for specific targeting of receptors present in cancer, for use with SPECT and PET non-invasive imaging. These imaging probes are labelled with the radioisotopes Tc-99m, F-18 or Ga-68.
BIRC scientists based at Lawson Imaging have the following technologies to develop exciting new imaging probes.
PET: PET is the most advanced medical diagnostic imaging technology available today. Due to their short half-lives, PET radionuclides need to be generated in close proximity to the PET scanner. Lawson has a fully qualified GMP facility to support the production of PET imaging probes for both clinical and preclinical studies.
SPECT: Currently, the team is researching solutions to the shortage of nuclear reactor-produced medical isotopes for imaging:
· Lawson and three partner organizations have been awarded $7 million by Natural Resources Canada (NRCan) NISP program to support production of cyclotron-based Technetium-99m (Tc-99m), the world’s most widely-used medical isotope. To date, we have ramped up to full-scale production levels, are working on validating production and quality control methods. The end of 2016, we will have completed a clinical trial, and with Health Canada approvals, develop supply chains to move toward commercialization of this technology.
· Clinical testing is underway on a new patented Tc-99m Cysteine Rhenium Colloid optimized for sentinel lymph node imaging to monitor the spread of breast cancer. This formulation reduces the amount of Tc-99m by up to 90%.
Imaging probes have been developed that target cancer cells and pancreatic beta cells for diabetes imaging (see also Molecular Imaging). FDG and the Avid Amyvid are approved for clinical use. Preclinical PET probes include FEPPA for neuroinflammation imaging, FFMZ for imaging neuroviability and [13N]ammonia for myocardial perfusion imaging Plans include:
· Development of new probes for PET or SPECT imaging of biomarkers, focusing on cancer, diabetes, heart disease and mental illnesses.
· Synthesizing Positron Emitting Radiopharmaceuticals (PERs), optimize their chemistry, and preparing them to GMP specifications for use in humans.
· Validation of probes via in vitro experiments in small animal μPET and μSPECT scanners.
· Verification using large animal imaging on a clinical PET/CT, SPECT/CT or PET/MRI scanner.
· Clinical trials to translate into clinical practice.
Michael Kovacs, PhD, Cyclotron & PET Radiochemistry
Leonard Luyt, PhD, SPECT Radiochemistry and Medicinal Chemistry
Pamela Zabel, MScPhm, Radiopharmacy