A novel Compton scatter camera design for in-vivo medical imaging of radiopharmaceuticals

A Compton scatter camera design is proposed for imaging radioisotopes used as biotracers. A clinical version may increase sensitivity by a factor of over 100, while maintaining or improving spatial resolution, as compared with existing Anger cameras. This novel approach is based on optimizing the camera design for data acquisition of gamma rays which undergo only one Compton scatter in a low-Z primary detector system followed by total absorption of the Compton scattered photon in a high-Z secondary detector system. By using energy subtraction (ΔE=E₀-E_SC), where E₀, ΔE, and E_SC are the energy of the emitted gamma ray, the energy deposited by the initial Compton scatter, and the energy of the Compton scattered photon to determine the amount of energy deposited in the primary system, the requirement of high energy resolution can be placed on the secondary system instead of the primary system. Requiring primary system high energy resolution has significantly limited previous Compton scatter camera designs for medical imaging applications. The proposed approach allows for close-packing of the primary detectors and a much less complicated detector cooling scheme. Analytical calculations and Monte Carlo simulation results for different detector materials and geometries are presented