[en] The feasibility of producing high-purity ¹⁶⁷Tm by spallation for use in nuclear medicine was investigated. Lutetium-oxide powder and hafnium, tantalum and tungsten foils were irradiated with 590-MeV protons. Cross sections for the formation of ¹⁶⁷Tm and contaminating ¹⁶⁸ Tm were determined; the best target material was tungsten with cross sections averaging 49 and 0.39 mbarns for ¹⁶⁷Tm and ¹⁶⁸Tm, respectively. The average amount of ¹⁶⁸Tm from the tungsten target was 0.09% of the ¹⁶⁷Tm activity and this equals the lowest contamination achieved with low-energy proton and ⁴He-ion-induced reactions. (author)