A radioactive implant induced X-ray emission (RIXE) technique was examined for the in vivo determination of heavy elements. By the use of67Ga,99mTc,123I,123Xe and201Tl implant excitation sources, the excitation efficiency and X-ray attenuation were measured to reveal the potential pairs of source-heavy element of interest for in vivo elemental analysis by the RIXE technique. Detection limits for the RIXE in vivo analysis were evaluated according to Currie's criterion. Four pairs,99mTc–Pb,201Tl–I,133Xe–Cd and123I–Cd are potential.