Positron emission tomography (PET) is firmly established as a clinical tool for molecular imaging with picomolar specificity, but its spatial resolution is fundamentally limited by the positron range, which amounts to a couple of millimeters. One idea to overcome the resolution limit of PET is to convert the positron emitted from a radiotracer to optical photons by placing a scintillator crystal right next to the specimen, instead of measuring annihilation gamma rays. Only a few methods have demonstrated the ability to visualize it on a single-cell resolution. Radioluminescence microscopy, demonstrated by a group of researchers at Stanford University, records individual positron tracks for monitoring the uptake of radioisotopes at a single-cell level. This new technology has many promising applications. For example, we can test new radiopharmaceuticals at high throughput before moving onto small animal or clinical trials. Further studies in measuring radiotracer kinetics in single cells will have the potential to make a great impact on nuclear medicine research in the future. We are developing 3-D radioluminescence imaging techniques with improved axial resolution and quantitativeness.

Related publications:

• Sung Y, Tétrault M, Takahashi K, Ouyang J, Pratx G, Normandin M, El Fakhri G. (2019). Dependence of fluorodeoxyglucose (FDG) uptake on cell cycle and dry mass: a single-cell study using a multi-modal radiography platform. Preprint at https://www.biorxiv.org/content/10.1101/668392v1.

Collaborators: Dr. Marc Normandin (Massachusetts General Hospital and Harvard Medical School), Dr. Kazue Takahashi (Massachusetts General Hospital and Harvard Medical School), Dr. Guillem Pratx (Stanford University).