Physical characterization of 3He ion beams for radiotherapy and comparison with 4He

There is increasing interest in using helium ions for radiotherapy, complementary to protons and carbon ions. A large number of patients were treated with He-4 ions in the US heavy ion therapy project and novel He-4 ion treatment programs are under preparation, for instance in Germany and Japan. He-3 ions have been proposed as an alternative to He-4 ions because the acceleration of He-3 is technically less difficult than He-4. In particular, beam contaminations have been pointed out as a potential safety issue for He-4 ion beams. This motivated a series of experiments with He-3 ion beams at Gesellschaft fur Schwerionenforschung (GSI), Darmstadt. Measured He-3 Bragg curves and fragmentation data in water are presented in this work. Those experimental data are compared with FLUKA Monte Carlo simulations. The physical characteristics of He-3 ion beams are compared to those of He-4, for which a large set of data became available in recent years from the preparation work at the Heidelberger Ionenstrahl-Therapiezentrum (HIT). The dose distributions (spread out Bragg peaks, lateral profiles) that can be achieved with He-3 ions are found to be competitive to He-4 dose distributions. The effect of beam contaminations on He-4 depth dose distribution is also addressed. It is concluded that He-3 ions can be a viable alternative to He-4, especially for future compact therapy accelerator designs and upgrades of existing ion therapy facilities.

Automated summary

This study explores the application of helium ions, particularly He-3, in radiotherapy and compares it with He-4 ions. It reveals the potential of He-3 as an alternative to He-4, showcasing competitive dose distributions. The findings emphasize the significance of He-3 ions for future compact therapy accelerator designs and upgrades of existing ion therapy facilities.