High‐spin states have been studied in the octupole‐deformed222Th nucleus using the208Pb(18O,4n) reaction. De‐excitation gamma rays were detected using the Euroball‐IV gamma‐ray spectrometer. The large background of gamma rays from prompt fission fragments, which generally hampers the spectroscopy of actinide nuclei in fusion‐evaporation reactions, has been reduced using the Euroball‐IV inner BGO ball as a sum‐energy filter. With the requirement that the summed gamma‐ray energy detected in the reaction is less than 10 MeV, the intensity of222Th gamma‐rays, relative to the prompt fission background is significantly improved. The experiment and data analysis are discussed, and preliminary spectroscopic results are presented. © 2003 American Institute of Physics