Monitoring response to radiotherapy in human squamous cell cancer bearing nude mice: Comparison of 2′-deoxy-2′-[18F]fluoro-d- glucose (FDG) and 3′-[18F]fluoro-3′-deoxythymidine (FLT)

Abstract

Objective: The uptake of 3′-[18F]fluoro-3′- deoxythymidine (FLT), a proliferation marker, was measured before and during fractionated radiotherapy to evaluate the potential of FLT-positron emission tomography (PET) imaging as an indicator of tumor response compared to 2′-deoxy-2′-[18F]fluoro-d-glucose (FDG). Materials and Methods: Nude mice bearing established human head and neck xenografts (HNX-OE; nu/nu mice) were locally irradiated (three fractions/week; 22 Gy) using a 150-kVp unit. Multiple FDG- and FLT-PET scans were acquired during treatment. Tumor volume was determined regularly, and tissue was analyzed for biomarkers involved in tracer uptake. Results: Both groups revealed a significant decline in tumor volume (P∈