Editorial: Charged Particles in Oncology

High-energy charged particles represent a cutting-edge technique in radiation oncology (1). Protons and carbon ions are used in several centers all over the world for the treatment of different solid tumors. Typical indications are ocular malignancies, tumors of the base of the skull, hepatocellular carcinomas, and various sarcomas (2). The physical characteristics of the charged particles (Bragg peak) allow sparing of much more normal tissues than it is possible using conventional X-rays (3), and for this reason, all pediatric tumors are considered eligible for proton therapy (4). Ions heavier than protons also display special radiobiological characteristics, which make them effective against radioresistant and hypoxic tumors (5). Protons and ions with high charge (Z) and energy (HZE particles) represent a major risk for human space exploration (6, 7). The main late effect of radiation exposure is cancer induction (8), and at the moment the dose limits for astronauts are based on lifetime cancer mortality risk (9, 10). The Mars Science Laboratory measured the dose on the route to Mars (11) and on the planet’s surface (12), supporting predictions that a human exploration mission to Mars will exceed the radiation risk limits (7, 13). Notwithstanding many studies on carcinogenesis induced by protons and heavy ions, the risk uncertainty remains high with important risk assessment questions to non-targeted effects (13) and the “quality” of HZE particle-induced tumors compared to spontaneous and photon-induced tumors (8). In this research topic, we invited scientists studying high-energy charged particles either for cancer treatment or for space radiation protection. We believe that space radiation protection and particle therapy share many common problems, and this research topic can be an inspiration to find applications and answers from fields that are apparently far away. Physics, biology, and medical contributions in this field will be found in the volume, owing to the fact that the field of charged particles in oncology is highly interdisciplinary. The research topics accepted 59 articles including a total of 351 authors, demonstrating the high interest in this field. It is in the top five most viewed research topics of this journal. The articles can be divided into the following topics.