¹⁸F-FET PET for planning of thermotherapy using magnetic nanoparticles in recurrent glioblastoma

Abstract

Purpose: Thermotherapy using magnetic nanoparticles (nano cancer therapy) is a new concept of local tumour therapy, which is based on controlled heating of intra-tumoural injected magnetic nanoparticles. The aim of this study was to evaluate the usefulness of PET with a recently introduced amino acid tracer O-(2-[¹⁸F]fluoroethyl)-]L-tyrosine (FET) for targeting the nanoparticles implantation.

Materials and methods: Eleven patients with glioblastoma recurrences underwent MR and FET-PET imaging for planning of the nano cancer therapy. Thereafter, the gross tumour volumes (GTV) were defined, taking into consideration the results of both imaging tools.

Results: The MRI-based mean GTV was 24.3 cm³ (range 2.5–59.7) and the PET-based mean GTV 31.9 cm³ (range 5.2–77.9). On the average the MRI identified an additional 8.9 ± 4.7 cm³ and the FET-PET scan—an additional 16.5 ± 15.2 cm³ outside of the common GTV (15.4 ± 11.0 cm³). The mean final GTV accounted to 33.8 cm³ (range, 5.2–77.9). The additional information of FET-PET led to an increase in GTV by 22–286% in eight patients and to a decrease of 23% and 26%, respectively, in two patients. In one patient, the final GTV was defined on the basis of MRI data only.

Conclusions: FET-PET adds important information on the actual tumour volume in recurrent glioblastomas and is highly valuable for defining the target volume for the nano cancer therapy.

• ¹⁸F-FET
• positron emission topography
• recurrent glioblastoma
• nano cancer therapy