The Reading Room Podcast: Current Challenges and Emerging Directions in Glioma Imaging

Is it recurrent tumor?

Is it residual tumor?

Is it post-treatment granulation tissue and inflammation?

These are common questions that arise when reviewing post-op MRIs after patients have undergone surgery or radiation treatment for brain tumors as these findings can look similar, noted Thomas Hope, MD, in a new Reading Room podcast episode.

“The biggest conundrum in glioma imaging is to distinguish between residual tumor and treatment-related effects,” noted Dr. Hope, the director of theranostics and vice chair of clinical operations and strategy in the Department of Radiology at the University of California, San Francisco (UCSF).

Dr. Hope is bullish aboutthe potential of the PET amino acid radiotracer floretyrosine F18 (¹⁸F-FET), which recently became the first PET radiopharmaceutical to garner FDA approval for the evaluation of glioblastoma multiforme (GBM). While noting that future studies will provide increased clarity on the use of ¹⁸F-FET (Pixclara, Telix Pharmaceuticals), Dr. Hope suggested the PET radiotracer will “ … improve dramatically molecular imaging of brain tumors moving forward.”

In the podcast, Dr. Hope pointed out that¹⁸F-FET offers key advantages in comparison to other PET imaging agents employed in cancer imaging and neuroimaging. For example, he noted that while fluorodeoxyglucose (FDG) PET is commonly utilized for cancer assessment, the high amount of glucose in the brain leads to a high uptake of FDG PET in normal brain. While the PET radiopharmaceutical fluorodopa ((¹⁸F)-DOPA), which is indicated for imaging of patients with Parkinson’s disease, has been utilized off-label for glioma imaging, Dr. Hope said the agent’s uptake in the basal ganglia hinders differentiation between residual tumor and normal brain structures.

“ … FET does not have those limitations,” maintained Dr. Hope.

Dr. Hope always suggested the potential utility of ¹⁸F-FET in serial PET imaging to differentiate between residual tumor and the effects of glioma treatment.

“It's that change over time that's going to become much more important and more accurate in distinguishing these very important clinical factors,” emphasized Dr. Hope.

For more insights from Dr. Hope, listen below or subscribe on your favorite podcast platform.

(Editor’s note: This podcast was originally published as an episode of our Molecular Imaging in Focus series at the following link: https://www.diagnosticimaging.com/view/molecular-imaging-in-focus-newly-fda-approved-pet-agent-floretyrosine-f18-glioma-imaging- .)