Objectives: The authors present the first use of the novel positron emission tomography (PET) apoptosis tracer (18)F-labeled 2-(5-fluoro-pentyl)-2-methyl-malonic acid ((18)F-ML-10) for early-therapy response assessment of a newly diagnosed glioblastoma multiforme (GBM) patient.
Case report: A 71-year-old male with a newly diagnosed GBM received (18)F-ML-10 PET scans prior to therapy initiation (baseline) and after completing 3 weeks of whole-brain radiation therapy with concomitant temozolomide chemotherapy (early-therapy assessment, ETA). The baseline (18)F-ML-10 PET scan showed increased tracer uptake at the site of the GBM, with highest activity toward the central portion of the tumor. At the ETA time point, a new distribution of tracer uptake was observed compared to baseline. Normalized pixel-by-pixel subtraction of baseline from ETA was used to quantify change in tracer distribution between (18)F-ML-10 PET imaging time points. Results of this analysis showed reduction in (18)F-ML-10 uptake at the site of greatest baseline uptake, but increased uptake around the periphery of the tumor at the early-therapy time point.
Conclusion: The changing patterns of (18)F-ML-10 uptake between baseline and ETA are suggestive for therapy-induced tumor cellular apoptosis.
Keywords: 18F-ML-10; early-therapy response assessment; glioblastoma multiforme; positron emission tomography.