High-throughput multiple-mouse imaging with micro-PET/CT for whole-skeleton assessment

Recent studies have proven that skeleton-wide functional assessment is essential to comprehensively understand physiological aspects of the skeletal system. Therefore, in contrast to regional imaging studies utilizing a multiple-animal holder (mouse hotel), we attempted to develop and characterize a multiple-mouse imaging system with micro-PET/CT for high-throughput whole-skeleton assessment. Using items found in a laboratory, a simple mouse hotel that houses four mice linked with gas anesthesia was constructed. A mouse-simulating phantom was used to measure uniformity in a cross sectional area and flatness (A_max/A_min*100) along the axial, radial and tangential directions, where A_max and A_min are maximum and minimum activity concentration in the profile, respectively. Fourteen mice were used for single- or multiple-micro-PET/CT scans. NaF uptake was measured at eight skeletal sites (skull to tibia). Skeletal ¹⁸F activities measured with mice in the mouse hotel were within 1.6±4% (mean±standard deviation) of those measured with mice in the single-mouse holder. Single-holder scanning yields slightly better uniformity and flatness over the hotel. Compared to use of the single-mouse holder, scanning with the mouse hotel reduced study time (by 65%), decreased the number of scans (four-fold), reduced cost, required less computer storage space (40%), and maximized ¹⁸F usage. The mouse hotel allows high-throughput, quantitatively equivalent scanning compared to the single-mouse holder for micro-PET/CT imaging for whole-skeleton assessment of mice.