Applied Radiation and Isotopes 64 (2006) 422–430 Improved separation methods for the recovery of 82 Sr from irradiated targets P. Sylvester 1 , T. Mo¨ller à , T.W. Adams Lynntech, Inc., 7610 Eastmark Drive, College Station, TX 77840, USA Received 15 November 2004; received in revised form 28 June 2005; accepted 16 August 2005 Abstract 82 Rb is a short-lived positron-emitting isotope (T 1=2 ¼ 75 s) that is increasingly being used in PET to study blood flow through the heart and brain. This isotope is supplied to physicians in the form of a generator where the parent isotope, 82 Sr, is immobilized onto an ion exchange column allowing the 82 Rb to be eluted with isotonic saline as required. 82 Sr is manufactured by the proton irradiation of molybdenum, rubidium chloride or rubidium metal targets followed by complex separations to recover the 82 Sr. A number of inorganic ion exchange materials were evaluated for their ability to remove 82 Sr from simulated target solutions and compared with currently used organic ion exchange resins. Sodium nonatitanate was identified as a replacement for current resins as a potential material that would simplify target processing and improve the yield of 82 Sr from each target. r 2005 Elsevier Ltd. All rights reserved. Keywords: 82 Sr; 82 Rb; Targets; Ion exchange; Sodium nonatitanate; PET 1. Introduction 82 Sr is the parent of 82 Rb, a short-lived radioisotope that is finding increasing use in Positron Emission Tomography (PET). The 82 Rb is supplied to physicians in the form of a generator where the 82 Sr is loaded onto an absorbent and the 82 Rb eluted when required. The current generators are manufactured by Bracco Diagnostics Inc., and distributed under the trade name CardioGen-82 s . As the use of 82 Rb increases, the demand for 82 Sr will also increase. 82 Sr is manufactured by the proton irradiation of rubidium, rubidium chloride or molybdenum targets followed by dissolution and processing to isolate the 82 Sr. The demand for 82 Rb generators has grown so great in recent years that Los Alamos National Laboratory (LANL) has resorted to importing irradiated target materials from the former Soviet Union and South Africa for processing in order to produce sufficient 82 Sr (Phillips et al., 2000). Consequently, ways to reduce processing times and to increase the yield of 82 Sr from processed targets are actively being sought. One method of improving the supply of 82 Sr is to improve the techniques used to extract 82 Sr from irradiated targets. Current methods utilize organic ion exchange or chelating resins to extract low concentrations of 82 Sr from dissolved targets contain- ing molar concentrations of inert ions. However, a satisfactory separation of 82 Sr from the target materials, and other radioisotopes generated during the irradiation procedure, requires multiple treatment steps due to the relatively low affinity and low selectivity of current organic ion exchange resins for 82 Sr. By utilizing a highly strontium-selective ion exchange material, the number of processing steps can be reduced, thus leading to a decrease in target processing times and a reduction in the cost of the 82 Sr product. In recent years, a number of strontium-selective inor- ganic ion exchange materials have been developed for the removal of 90 Sr from nuclear wastes (Sylvester and Clearfield, 1998, 1999; Anthony et al., 2000; Lehto et al., 1999). These materials are far superior to previously used hydrous oxides, such as ZrO 2 , SnO 2 , Al 2 O 3 and MnO 2 , and have high selectivities for strontium over alkali and other alkaline earth metals. Consequently, they are ideally suited ARTICLE IN PRESS www.elsevier.com/locate/apradiso 0969-8043/$ - see front matter r 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.apradiso.2005.08.014 à Corresponding author. Tel.: +1 508 393 5115; fax: +1 508 393 1795. E-mail address: Tmoller@solmetex.com (T. Mo¨ller). 1 Current address: SolmeteX, 50 Bearfoot Road, Northborough, MA 01532, USA.