Biomaterial Database

Approaches to radiation guidelines for space travel. 1984

R J Fry

Biology Division, Oak Ridge National Laboratory, TN 37831, USA.

There are obvious risks in space travel that have loomed larger than any risk from radiation. Nevertheless, NASA has maintained a radiation program that has involved maintenance of records of radiation exposure, and planning so that the astronauts' exposures are kept as low as possible, and not just within the current guidelines. These guidelines are being reexamined currently by NCRP Committee 75 because new information is available, for example, risk estimates for radiation-induced cancer and about the effects of HZE particles. Furthermore, no estimates of risk or recommendations were made for women in 1970 and must now be considered. The current career limit is 400 rem to the blood forming organs. The appropriateness of this limit and its basis are being examined as well as the limits for specific organs. There is now considerably more information about age-dependency for radiation effects and this will be taken into account. In 1973 a committee of the National Research Council made a separate study of HZE particle effects and it was concluded that the attendant risks did not pose a hazard for low inclination near-earth orbit missions. Since that time work has been carried out on the so-called microlesions caused by HZE particles and on the relative carcinogenic effect of heavy ions, including iron. A remaining question is whether the fluence of HZE particles could reach levels of concern in missions under consideration. Finally, it is the intention of the committee to indicate clearly the areas requiring further research.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008452	Maximum Allowable Concentration	The maximum exposure to a biologically active physical or chemical agent that is allowed during an 8-hour period (a workday) in a population of workers, or during a 24-hour period in the general population, which does not appear to cause appreciable harm, whether immediate or delayed for any period, in the target population. (From Lewis Dictionary of Toxicology, 1st ed)	Maximum Permissible Exposure Level,MPEL,Maximum Permissible Exposure Concentration,Allowable Concentration, Maximum,Allowable Concentrations, Maximum,Concentration, Maximum Allowable,Concentrations, Maximum Allowable,MPELs,Maximum Allowable Concentrations
D009381	Neoplasms, Radiation-Induced	Tumors, cancer or other neoplasms produced by exposure to ionizing or non-ionizing radiation.	Radiation-Induced Cancer,Cancer, Radiation-Induced,Radiation-Induced Neoplasms,Cancer, Radiation Induced,Cancers, Radiation-Induced,Neoplasm, Radiation-Induced,Neoplasms, Radiation Induced,Radiation Induced Cancer,Radiation Induced Neoplasms,Radiation-Induced Cancers,Radiation-Induced Neoplasm
D011829	Radiation Dosage	The amount of radiation energy that is deposited in a unit mass of material, such as tissues of plants or animal. In RADIOTHERAPY, radiation dosage is expressed in gray units (Gy). In RADIOLOGIC HEALTH, the dosage is expressed by the product of absorbed dose (Gy) and quality factor (a function of linear energy transfer), and is called radiation dose equivalent in sievert units (Sv).	Sievert Units,Dosage, Radiation,Gray Units,Gy Radiation,Sv Radiation Dose Equivalent,Dosages, Radiation,Radiation Dosages,Units, Gray,Units, Sievert
D011835	Radiation Protection	Methods and practices adopted to protect against RADIATION.	Protection, Radiation
D012062	Relative Biological Effectiveness	The ratio of radiation dosages required to produce identical change based on a formula comparing other types of radiation with that of gamma or roentgen rays.	Biological Effectiveness, Relative,Effectiveness, Biologic Relative,Effectiveness, Biological Relative,Relative Biologic Effectiveness,Biologic Effectiveness, Relative,Biologic Relative Effectiveness,Biological Relative Effectiveness,Effectiveness, Relative Biologic,Effectiveness, Relative Biological,Relative Effectiveness, Biologic
D003359	Cosmic Radiation	High-energy radiation or particles from extraterrestrial space that strike the earth, its atmosphere, or spacecraft and may create secondary radiation as a result of collisions with the atmosphere or spacecraft.	HZE Particles,Radiation, Cosmic,Cosmic Radiations,HZE Particle,Particle, HZE,Particles, HZE,Radiations, Cosmic
D004307	Dose-Response Relationship, Radiation	The relationship between the dose of administered radiation and the response of the organism or tissue to the radiation.	Dose Response Relationship, Radiation,Dose-Response Relationships, Radiation,Radiation Dose-Response Relationship,Radiation Dose-Response Relationships,Relationship, Radiation Dose-Response,Relationships, Radiation Dose-Response
D005118	Extraterrestrial Environment	The environment outside the earth or its atmosphere. The environment may refer to a closed cabin (such as a space shuttle or space station) or to space itself, the moon, or other planets.	Space (Astronomy),Environment, Extraterrestrial,Environments, Extraterrestrial,Extraterrestrial Environments,Spaces (Astronomy)
D005260	Female		Females