Mortazavi S M J
Medical Physics Department, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
Technol Health Care. 2013;21(4):285-9. doi: 10.3233/THC-130732.
Energetic solar particle events (SPE) which are among the main sources of ionizing radiation can be life threatening to astronauts who are not adequately protected. To date, physical shielding of spacecrafts and inducing radioresistance by using radioprotectors have been proposed by different investigators. Mortazavi et al. have previously reported that screening of the candidates of long-term space missions by conducting Ground-based in vitro adaptive response studies before any mission identifies the individuals who respond well to low levels of ionizing radiation and reveal high magnitudes of radioadaptive response. On the other hand, Mortazavi et al. have recently showed that radiofrequency-induced adaptive response can be used as a method for decreasing the risk of infection caused by immunosuppression during deep space missions. Furthermore, over the past years the radioresistance induced by a wide variety of radioprotectors has been studied. According to classical radiobiology, chemical radioprotective agents must be administered before irradiation or at the time of irradiation, to increase the mean survival rate of the exposed individuals. A revolution in this paradigm was started in 2010, when investigators reported that a diet supplemented with antioxidants administered starting 24 h after total-body irradiation is more effective than if given soon after the exposure (radiation mitigation). This finding along with the above mentioned interventions open new horizons in inducing biological radioresistance against unpredictable high levels of radiation due to solar particle events. This wide time window indeed enables astronauts to firstly evaluate their radiation doses before making any decision on the type of intervention. As major solar particle events last for hours, astronauts will be able to consult distinguished radiation biologists via satellite telecommunication before choosing any medical intervention.
高能太阳粒子事件（SPE）是电离辐射的主要来源之一，对于未得到充分保护的宇航员可能会危及生命。迄今为止，不同的研究人员提出了对航天器进行物理屏蔽以及使用辐射防护剂诱导抗辐射性的方法。莫尔塔扎维等人此前曾报道，在任何任务之前通过开展地面体外适应性反应研究来筛选长期太空任务的候选人，可以识别出对低水平电离辐射反应良好并表现出高幅度辐射适应性反应的个体。另一方面，莫尔塔扎维等人最近表明，射频诱导的适应性反应可作为一种方法，用于降低深空任务期间因免疫抑制引起的感染风险。此外，在过去几年中，人们对多种辐射防护剂诱导的抗辐射性进行了研究。根据经典放射生物学，化学辐射防护剂必须在照射前或照射时给药，以提高受照个体的平均存活率。2010年，这一范式发生了变革，当时研究人员报告称，在全身照射后24小时开始补充抗氧化剂的饮食比在照射后不久给予更有效（辐射缓解）。这一发现以及上述干预措施为诱导针对因太阳粒子事件导致的不可预测的高水平辐射的生物抗辐射性开辟了新的前景。这个较宽的时间窗口确实使宇航员能够在对干预类型做出任何决定之前首先评估他们的辐射剂量。由于主要的太阳粒子事件持续数小时，宇航员将能够在选择任何医疗干预措施之前通过卫星通信咨询杰出的辐射生物学家。
