Document Type: Commentary


1 PhD,Bevelacqua Resources, 343 Adair Drive, Richland, WA 99352, USA

2 PhD,Medical Physics Department, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran

3 PhD, Diagnostic Imaging Department, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111, USA


The radiation environment in deep space, where astronauts are behind the shelter provided by the Earth’s magnetosphere, is a major health concern. Galactic cosmic rays (GCR) and solar particle events (SPE) are two basic sources of space radiation in the solar system. The health risks of exposure to high levels of space radiation can be observed either as acute and delayed effects. Zhang et al. in their recently published paper entitled “γ-H2AX responds to DNA damage induced by long-term exposure to combined low-dose-rate neutron and γ-ray radiation” have addressed the effects of different cumulative radiation doses on peripheral blood cell, subsets of T cells of peripheral blood lymphocytes and DNA damage repair. These researchers exposed animals to low dose rate 60Co-rays at 0.0167 Gy h−1for 2 h/d and 252Cf neutrons at 0.028 mGy h−1for 20 h/d for 15, 30, or 60 consecutive days. They reported that the mRNA of H2AX increased significantly, and showed a positive correlation with dose. Despite strengths, this paper has several shortcomings such as poor definition of low dose radiation as well as space and reactor radiation environments. Another shortcoming of this paper comes from this point that blood cell studies do not represent the biological effects of ionizing radiation on the total body. Moreover, the effects of the human immune system and DNA repair mechanisms are not included in the study. The role of pre-exposures and induction of adaptive response phenomena in decreasing the risk of radiation in deep space missions are also ignored.


  1. Zhang J, He Y, Shen X, Jiang D, Wang Q, Liu Q, et al. γ-H2AX responds to DNA damage induced by long-term exposure to combined low-dose-rate neutron and γ-ray radiation. Mutation Research/Genetic Toxicology and Environmental Mutagenesis. 2016;795:36-40. doi: 10.1016/j.mrgentox.2015.11.004.
  2. Bevelacqua JJ. Health physics in the 21st century: John Wiley & Sons; 2008.
  3. Bevelacqua JJ. Contemporary health physics: problems and solutions: John Wiley & Sons; 2009.
  4. Bevelacqua JJ. Health physics: radiation-generating devices, characteristics, and hazards: John Wiley & Sons; 2016.
  5. Bevelacqua JJ. Radiation protection consequences of the emerging space tourism industry. JJ Earth Science. 2017;1:1-11.
  6. Bevelacqua JJ. Health physics aspects of generation IV reactors. International Nuclear Safety Journal. 2014;3:13-37.
  7. Mortazavi SM. Space radiobiology and the new era of induced radioresistance: should traditional concepts be moved to science history museums? Technol Health Care. 2013;21:285-9. doi: 10.3233/THC-130732. PubMed PMID: 23949175.
  8. Mortazavi S, Mozdarani H. Deep space missions and the issue of overcoming the problem of space radiation. International Journal of Radiation Research. 2013;11:199-202.
  9. Mortazavi SM, Cameron JR, Niroomand-rad A. Adaptive response studies may help choose astronauts for long-term space travel. Adv Space Res. 2003;31:1543-51. PubMed PMID: 12971409. doi: 10.1016/s0273-1177(03)00089-9.
  10. Bevelacqua JJ, Mortazavi SMJ. Commentary: Human Pathophysiological Adaptations to the Space Environment. Front Physiol. 2017;8:1116. doi: 10.3389/fphys.2017.01116. PubMed PMID: 29358922; PubMed Central PMCID: PMC5766677.
  11. Bevelacqua JJ, Welsh J, Mortazavi SMJ. Comments on ‘An overview of space medicine’. Br J Anaesth. 2018;120:874-6. doi: 10.1016/j.bja.2017.12.015. PubMed PMID: 29576129.
  12. Bevelacqua JJ, Mortazavi SMJ. Commentary: Immune System Dysregulation During Spaceflight: Potential Countermeasures for Deep Space Exploration Missions. Front Immunol. 2018;9:2024. doi: 10.3389/fimmu.2018.02024. PubMed PMID: 30233600; PubMed Central PMCID: PMC6131484.
  13. Huff J, Carnell L, Blattnig S, Chappell L, Kerry G, Lumpkins S, et al. Evidence report: risk of radiation carcinogenesis. 2016.
  14. Cortese F, Klokov D, Osipov A, Stefaniak J, Moskalev A, Schastnaya J, et al. Vive la radioresistance!: converging research in radiobiology and biogerontology to enhance human radioresistance for deep space exploration and colonization. Oncotarget. 2018;9:14692-722. doi: 10.18632/oncotarget.24461. PubMed PMID: 29581875; PubMed Central PMCID: PMC5865701.