In vivo spatial correlation between ¹⁸F-BPA and ¹⁸F-FDG uptakes in head and neck cancer

Background and purpose Borono-2-¹⁸F-fluoro-phenylalanine (¹⁸F-BPA) has been used to estimate the therapeutic effects of boron neutron capture therapy (BNCT), while ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) is the most commonly used positron emission tomography (PET) radiopharmaceutical in a routine clinical use. The aim of the present study was to evaluate spatial correlation between ¹⁸F-BPA and ¹⁸F-FDG uptakes using a deformable image registration-based technique. Material and methods Ten patients with head and neck cancer were recruited from January 2014 to December 2014. All patients underwent whole-body ¹⁸F-BPA PET/computed tomography (CT) and ¹⁸F-FDG PET/CT within a 2-week period. For each patient, ¹⁸F-BPA PET/CT and ¹⁸F-FDG PET/CT images were aligned based on a deformable image registration framework. The voxel-by-voxel spatial correlation of standardized uptake value (SUV) within the tumor was analyzed. Results Our image processing framework achieved accurate and validated registration results for each PET/CT image. In 9/10 patients, the spatial distribution of SUVs between ¹⁸F-BPA and ¹⁸F-FDG showed a significant, positive correlation in the tumor volume. Conclusions Deformable image registration-based voxel-wise analysis demonstrated a spatial correlation between ¹⁸F-BPA and ¹⁸F-FDG uptakes in the head and neck cancer. A tumor sub-volume with a high ¹⁸F-FDG uptake may predict high accumulation of ¹⁸F-BPA.