Molecular Radiobiology of Protons Compared to Other Low Linear Energy Transfer (LET) Radiation

Dear Colleagues,

Advanced radiation delivery systems offer significant benefits in cancer treatment; however, there is potential for harm to normal tissue. There is strong and growing interest in proton radiation due to its use in cancer treatment, its prominent role in space radiation exposure, and its ability to inflict a substantial portion of the biological damage caused by neutrons. Protons are a type of low linear energy transfer (LET) radiation, such as X-rays or electrons, that covers a wide energy range. However, at low energies near the Bragg peak (<5 MeV), they become high LET. High-energy protons (>50 MeV) generate copious amounts of secondary radiation, including neutrons and high-LET charged particles. In addition, there is growing interest in advanced radiation modalities, including ultra-high dose rate (FLASH) proton irradiation. There is significant overlap in the approaches used to elucidate molecular mechanisms in the areas of radiation cancer treatment as well as the risks in the diagnostic use of radiation and to radiation workers on Earth and in space. Research in these areas has seen substantial progress in recent years, and this Special Issue aims to provide a comprehensive overview of the biomolecular changes caused by proton radiation and comparisons with X-rays and other low LET radiation. We encourage the submission of original full research papers as well as review articles that present novel mechanistic insights, new techniques, experimental models, predictive theoretical models, and datasets.

Topics include, but are not limited to, the following:

• Comparisons of protons to X-rays and electrons of varying energies in cancer therapy and normal tissue damage;
• Initial and persistent DNA and reactive oxygen species (ROS) damage, damage processing, and aberrant signaling in cells and tissue;
• Creation of omics databases of proton effects;
• Use of artificial intelligence and machine learning in describing and comparing protons with other low LET radiation molecular changes related to health risks;
• Immune-proton therapy;
• Molecular changes causative of non-cancer effects such as cognitive impairments, cataracts, and circulatory disease risks following proton radiation exposure;
• FLASH proton irradiation;
• Molecular changes leading to health risks from solar particle events and cosmic rays.

Prof. Dr. Francis Cucinotta
Prof. Dr. Jacob Raber
Topic Editors