According to data on Y-90 published by Klett et al. [12], the median absorbed doses to the liver and spleen were 62 and 62 mGy, respectively. Somewhat higher mean doses for the liver, spleen, and kidneys (265, 119, and 671 mGy) were reported by Gratz et al. [1]. The organ doses to the liver and spleen published by Klett et al. [12] are consistent with mean leakage to the blood system of about 2 %. While the spleen doses reported by Gratz et al. [1] are consistent with 2 % leakage, the liver doses are higher requiring 8 % leakage. The high kidney doses are not consistent with the model assumptions.

Reliable measurements of the whole body activity after administration of Er-169 are not available as almost no direct radiation leaves the body. Manil et al. [3] measured the total blood activity after Er-169 therapy of finger joints in 11 patients and found less than 1 % of the administered activity in all but 1 patient with scintigraphic evidence of extra-articular injection. The effective dose was maximal for this patient and was estimated to be 0.045 mSv/MBq. For Er-169 Gratz et al. [1] estimated the radiation dose to the whole body to be 0.11 mGy/MBq.