Attenuation of radionuclide activity by metal-cup arthroplasties

The half-value layers of stainless steel, bone cement, and polyethylene were measured for 99mTc, 67Ga, 111In, and 201TI to render some insight into the attenuating effects of the metallic cup and other components used in surface-replacement revision arthroplasty. On theoretic consideration, a twofold increase in 99mTc-methylene diphosphonate in bone inside the cup should not be attenuated to the point of escaping detection on the radionuclide images of the hip. 67Ga, using the 184 and 300 keV peaks, and 111In have greater half-value layers than 99mTc and are subject to less attenuation by the metallic cup.