Integrin-PET uptake evaluation in patients receiving pulmonary radiotherapy

In this study, the utility of PET imaging with a αvβ6 integrin ligand was evaluated in patients with non-small cell lung cancer following pulmonary RT. Subjects with NSCLC who had received pulmonary RT within 6 months were recruited. PET imaging of the lungs over 60 minutes was performed after administration of a fluorine-18 radiolabelled 20 amino acid αvβ6-specific peptide ligand, [18F]-FBAA20FMDV2 (IMAFIB; Cancer Research Technologies (CRT) patented). PET-CT scans were co-registered with the RT planning (RTP) scans and segmented to regions corresponding to RT doses of > 40 Gy (excluding tumour), 25-40 Gy, 15-25 Gy, 8-15 Gy and < 8 Gy. Time activity curves and the standardised uptake values (SUVs) were calculated and comparisons made between RT dose and PET uptake (SUV). Linear regression between SUV and RT dose was performed for each subject and normalised to an intercept of 1. Six subjects (3M; 3F) aged 51-75 years underwent an IMAFIB-PET scan between 6 - 22 weeks after RT completion and mean IMAFIB radioactivity of 45.4 (range 8.9 - 122) MBq administered. Five subjects received conformal external beam RT, while one subject received stereotactic RT (SBRT). Biological effective doses (BED) using the linear quadratic cell survival radiobiology model [2] were calculated for pneumonitis (α/β = 5) and lung fibrosis (α/β = 3). The averaged normalised SUV across all subjects increased monotonically with RT dose (figure), between 1...
Source: Journal of Nuclear Medicine - Category: Nuclear Medicine Authors: Tags: Outcomes/Infectious Disease/Pulmonary II Source Type: research