Standardized Uptake Value in High Uptake Area on Positron Emission Tomography with 18F-FRP170 as a Hypoxic Cell Tracer Correlates with Intratumoral Oxygen Pressure in Glioblastoma

Abstract

The aim of this study was to clarify the reliability of positron emission tomography (PET) using a new hypoxic cell tracer, 1-(2-[(18)F]fluoro-1-[hydroxymethyl]ethoxy)methyl-2-nitroimidazole ((18)F-FRP170). Twelve patients with glioblastoma underwent (18)F-FRP170 PET before tumor resection. Mean standardized uptake value (SUV) and normalized SUV were calculated at regions within a tumor showing high (high-uptake area) and relatively low (low-uptake area) accumulations of (18)F-FRP170. In these areas, intratumoral oxygen pressure (tpO2) was measured using microelectrodes during tumor resection. Mean tpO2 was significantly lower in the high-uptake area than in the low-uptake area. A significant negative correlation was evident between normalized SUV and tpO2 in the high-uptake area. The present findings suggest that high accumulation on (18)F-FRP170 PET represents viable hypoxic tissues in glioblastoma.