Radiation Dosimetry Of Yb-169 DTPA In Cisternography

Abstract

SUMMARY Equilibrium absorbed dose contributions for radiations emitted by 169Yb have been derived and utilized in the calculation of doses to the spinal cord and nerve roots from intrathecally administered 169Yb‐DTPA. Mean doses to the whole body and gonads have also been determined and compared with doses calculated for 131I‐HSA and 99mTc‐HSA. The spinal cord pia mater surface dose from 169Yb‐DTPA is comparable to that from 131I‐HSA, while the dose at the base of the pia mater is about half that from 131I‐HSA. For an injected activity of 1 mCi the dose to the pial surface from 169Yb‐DTPA is about 70 ±30 rads and that to the base of the pia about 17 ±8 rads.