Dosimetry of four heart-imaging radionuclides: 43K, 81Rb, 129Cs, and 201Ti.

In conjunction with research into the relative clinical suitability of radionuclides for heart imaging, estimates of the radiation dosimetry for 43K, 81Rb, 129Cs, and 201Tl were calculated. Estimates of absorbed radiation dose for the heart, kidneys, liver, lungs, testes, and whole body of the standard man were computed from published distribution data in rats via the MIRD method by assuming that the concentration in each organ per initial mean whole-body concentration is the same in rats and humans. The whole-body absorbed radiation doses from 81Rb, 129Cs, 201Tl, and 43K are 0.08, 0.17, 0.24, and 0.60 rads/mCi administered intravenously. In general, the organ doses from the four radionuclides follow the same order.