The Mirion ACT-LC Ge Detector was designed specifically for the detection of internally deposited actinides, particularly uranium, plutonium and americium. Because of the low gamma-ray abundance from uranium, and the low energy of the x rays from plutonium, which emits few gammas, this application demands a very specialized detector system. To achieve desired sensitivities, two large area Broad Energy Germanium (BEGe™) detectors are placed in virtual contact with the subject in close proximity to the lungs. The measurement must be carried out in a shielded room. For optimum results, the detectors must be closely spaced, the detector background must be low, the resolution must be good, and the sensitivity of the detector must be high over the energy range of interest (13-20 keV for Pu, 60 keV for Am, and 140-190 keV for U). The ACT-LC Ge Detector from Mirion provides all this performance and more.