Researchers at the University of Louiseville Kentucky have demonstrated the effectiveness of a new radiotracer,called 2-18F-fluorodeoxysorbitol (18F-FDS), for tracking bacterial infection in lungs. According to the paper, which was published in the January issue of The Journal of Nuclear Medicine, this tracer shows improvement over current imaging methods used for this purpose and is able to differentiate bacterial infection from inflammation.
For the study, mice were inoculated with live Klebsiella pneumoniae or the dead form to induce inflammation. Half of the the mice inoculated with live bacteria were imaged with PET/CT using either 18F-FDS or 18F-FDG, a commonly used radiotracer. The other half were screened using bioluminescent imaging with follow-up PET/CT scans with 18F-FDS for those with visible infection. In the inflammation group, half were imaged using 18F-FDS and half using 18F-FDG from day 1 to day 4 post-inoculation.
Both 18F-FDS and 18F-FDG were able to effectively track the degree of bacterial infection measured by bioluminescent optical imaging, but only 18F-FDS was able to differentiate between lung infection and lung inflammation.
The researchers are hopeful for a straightforward approval pathway for 18F-FDS by the U.S. Food and Drug Administration since it can be made from 18F-FDG with a simple conversion step and sorbitol has already been approved.
Image: Representative PET/CT images of 18F-FDS and 18F-FDG in Inflamed Mice. Mice were inoculated with dead K. pneumoniae (10^8 CFU/mL). Imaging was performed for days 1, 2, 3 and 4 using 18F-FDG and 18F-FDS. CT images showed clear inflammation on day 2 and day 3 with corresponding high 18F-FDG uptake on PET. No significant uptake of 18F-FDS was detected for any of those 4 days. Image courtesy of J Li et al., University of Louisville School of Medicine, Louisville, KY.