Sr/Y separation by supported liquid membranes based on nuclear track micro filters

Abstract

First results of experiments concerning the preparation of a Y-90 generator are presented. The aim of this work is to prepare a rather cost-effective and easy to maintain Y-90 generator that produces Y-90 solutions of sufficient purity for their subsequent application in radionuclide therapy. Besides the need for high purity of the Y-90 solutions, it has to be taken into account that high activities are involved (up to 2 Ci Sr-90). Consequently, materials with very good radiation stability must be used for the construction of the generator. Nuclear track micro filters (NTMFs) prepared from polyimide foils are renowned for their outstanding radiolytical and chemical stability. In addition to that they have the distinct advantage that pore size and porosity can be chosen and optimized for each application. The NTMFs are used as supported liquid membranes (SLM) after impregnating them with a 1:1 mixture of bis-(2-ethylhexyl)-phosphate (HDEHP) and tributylphosphate (TBP). Y-90 separation from its parent Sr-90 is achieved by its selective transport through the pores of the impregnated NTMF. The Y-90 activity of the prepared solutions is determined by means of Cerenkov-counting, the Sr-90 content is calculated after determining the activity of an internal standard, namely Sr-85, by low-level gamma-spectrometry. It was shown that a separation of Y-90 and Sr-90 using NTMFs impregnated with an appropriate extractant is possible.