A Compton Camera System for Whole-Body Targeted Alpha Therapy Imaging

We simulate a novel Compton camera imaging device designed for whole-body imaging and targeted radionuclide therapy, addressing a major limitation in targeted alpha therapy: the low administered doses and the insufficient gamma photon yield for conventional SPECT imaging. The proposed system features a fixed and a zooming scatterer-absorber detector pair, providing a field of view (FOV) suitable for whole-body applications while maintaining high sensitivity and clinically relevant resolution within a practical scan time. Imaging performance was evaluated using the GATE Monte Carlo simulation toolkit with point sources of 99mTc, 177Lu, and 225Ac, representing diagnostic, beta-emitting, and alpha-emitting radionuclides, respectively. Image reconstruction was performed using a NEMA IQ phantom of human torso size filled with 99mTc and 225Ac at clinically relevant doses, including full decay chain simulation. Results indicate that the proposed Compton camera enables effective imaging of the alpha-emitter 225Ac at activity levels as low as 5.7 MBq in a water-equivalent background, highlighting its potential for advancing clinical alpha therapy imaging.