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Prof. SMJ Mortazavi
Ionizing and Non-ionizing Radiation Protection Research Center (INIRPRC), Iran
Title:
How Can Biological Methods Decrease Radiation Risk in Long-Term Manned Space Missions
Abstract:
Exposure to high levels of space radiation is an important concern for astronauts participating in long term space missions. Mortazavi et al have previously reported that screening of the candidates for long-term space missions by conducting Ground-based in vitro adaptive response studies before any mission can identify the individuals who respond well to low levels of ionizing radiation and reveal high magnitudes of radioadaptive response. They hypothesized that in space, chronic exposure to higher than on-Earth levels of radiation can greatly decrease radiation susceptibility of astronauts and help them better cope with the detrimental effects of the exposure to unpredictable sudden solar flares and coronal mass ejections. On the other hand, Mortazavi et al have recently reported that based on their findings on an animal model, radiofrequency-induced adaptive response can be used as a method for decreasing the risk of infection during deep space missions. In long-term deep space missions, astronauts will be exposed to both chronic space radiation and acute high doses of energetic radiation of solar particle events. It is well known that application of radioprotectors in space missions has very basic limitations such as their very short time window because they must be administered before exposure or at the time of exposure, their acute toxicity and considerable side effects. Therefore, Mortazavi et al. have recently shown that vitamin C can be administered 24 h after total-body irradiation to significantly increase the survival rate of the exposed animals. This finding may be a key method in decreasing the risk of high levels of radiation caused by solar particle events in long term space missions. 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. The wide time window (24 h) investigated in our experiment, enables astronauts to firstly evaluate their radiation doses before making any decision on the type of medical interventions. As major solar particle events last for hours, astronauts will be able to consult expert radiation biologists via satellite telecommunication before choosing the dose of vitamin C and any other medical intervention.
Biography:

SMJ Mortazavi currently holds the position of president of the Ionizing and Non-ionizing Radiation Protection Research Center (INIRPRC). He also serves as Professor of Medical Physics in the School of Medicine of Shiraz University of Medical Sciences (SUMS). Mortazavi has authored more than 110 papers in peer reviewed journals in the areas such as non-ionizing radiation, radiation protection, dosimetry, natural radiation, radiation hormesis, radioadaptive response and the possible role of radioadaptive response in radiation protection. He has also published papers on radiation protection in manned space missions. 

Professor SMJ Mortazavi‚Äôs reports on the health effects of exposure to high levels of natural radiation in high background radiation areas of Ramsar have been widely cited (one is cited 114 times in the Web of Science).The radioactivity of the high background radiation areas of Ramsar is due to Ra-226 and its decay products, which have been brought to the surface by the waters of hot springs. There are more than 9 hot springs with different concentrations of radium in Ramsar that are used as spas by both tourists and residents. While it was generally believed that high levels of natural radiation in these areas is harmful for the inhabitants, Mortazavi and his colleagues showed that exposure to extraordinary levels of natural background radiation can induce radioadaptive response in human cells. Lymphocytes of Ramsar residents when subjected to 1.5 Gy of gamma rays showed fewer induced chromosome aberrations compared to residents in a nearby control area whose lymphocytes were subjected to the same radiation dose. Results obtained in their studies were generally consistent with the hypothesis that a threshold possibly separates the health effects of natural radiation from the harm of large doses. This threshold seems to be much higher than the greatest level of natural radiation. 

He has also published papers on the future role of radioadaptation in the long-term stay of humans in space. Mortazavi et al. in 2003 presented this novel concept that after in vitro Ground-based tests and screening of the candidates for selection of the individuals with the highest magnitude of adaptive response, prior radiation exposure to continuous isotropic galactic cosmic radiation (GCR) during any mission might induce an adaptive response in astronauts to better protect them against high levels of radiation in an unpredictable solar particle event (SPE). (This paper is cited 19 times in the Web of Science).

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