Cyclotron production of thallous chloride (201Tl) injection

The production of thallous chloride (201Tl) injection is described. 201Tl was produced via nuclear reaction of 203Tl (p, 3n) 201Pb using natural thallium in a specially designed 2π cooling target system. The separation of Pb-activity from the Tl target was carried out by extraction of Tl(III) with isopropyl ether and purification of Pb(II) with an anion exchanger (201 x 8 resin) column. After a decay time of 32h, during which an optimum growth of 201Tl took place, carrier-free 201Tl was separated from the 203Pb activities by a second similar anion exchanger. Dependences of the percentage extraction of Tl(III) from HCl solution into isopropyl ether on acidity and concentration of Tl(III) in aqueous phase were determined. The thick target yield of 201Tl is 18.8 MBq/μAh. The product possesses a radioisotopic purity of > 99% and a radiochemical purity of > 98%. It is a sterile, isotonic and pyrogen-free solution with a Tl content of 0.27 x 10-7 μg/Bq