Annals of the ICRP最新文献

The International Commission on Radiological Protection (ICRP) developed effective dose as a quantity related to risk for occupational and public exposure. There was a need for a similar dose quantity linked to risk for making everyday decisions relating to medical procedures. Coefficients were developed to enable the calculation of doses to organs and tissues, and effective doses for procedures in nuclear medicine and radiology during the 1980s and 1990s. Effective dose has provided a valuable tool that is now used in the establishment of guidelines for patient referral and justification of procedures, choice of appropriate imaging techniques, and providing dose data on potential exposure of volunteers for research studies, all of which require the benefits from the procedure to be weighed against the risks. However, the approximations made in the derivation of effective dose are often forgotten, and the uncertainties in calculations of risks are discussed. An ICRP report on protection dose quantities has been prepared that provides more information on the application of effective dose, and concludes that effective dose can be used as an approximate measure of possible risk. A discussion of the way in which it should be used is given here, with applications for which it is considered suitable. Approaches to the evaluation of risk and methods for conveying information on risk are also discussed.

[Formula: see text]There is a growing desire amongst space-faring nations to venture beyond the Van Allen radiation belts to a variety of intriguing locations in our inner solar system. Mars is the ultimate destination. In two decades, we hope to vicariously share in the adventure of an intrepid crew of international astronauts on the first voyage to the red planet.This will be a daunting mission with an operational profile unlike anything astronauts have flown before. A flight to Mars will be a 50-million-kilometre journey. Interplanetary distances are so great that voice and data communications between mission control on Earth and a base on Mars will feature latencies up to 20 min. Consequently, the ground support team will not have real-time control of the systems aboard the transit spacecraft nor the surface habitat. As cargo resupply from Earth will be impossible, the onboard inventory of equipment and supplies must be planned strategically in advance. Furthermore, the size, amount, and function of onboard equipment will be constrained by limited volume, mass, and power allowances.With less oversight from the ground, all vehicle systems will need to be reliable and robust. They must function autonomously. Astronauts will rely on their own abilities and onboard resources to deal with urgent situations that will inevitably arise.The deep space environment is hazardous. Zero- and reduced-gravity effects will trigger deconditioning of the cardiovascular, musculoskeletal, and other physiological systems. While living for 2.5 years in extreme isolation, Mars crews will experience psychological stressors such as loss of privacy, reduced comforts of living, and distant relationships with family members and friends.Beyond Earth's protective magnetosphere, the fluence of ionising radiation will be higher. Longer exposure of astronauts to galactic cosmic radiation could result in the formation of cataracts, impaired wound healing, and degenerative tissue diseases. Genetic mutations and the onset of cancer later in life are also possible. Acute radiation sickness and even death could ensue from a large and unpredictable solar particle event.There are many technological barriers that prevent us from carrying out a mission to Mars today. Before launching the first crew, we will need to develop processes for in-situ resource utilisation. Rather than bringing along large quantities of oxygen, water, and propellant from Earth, future astronauts will need to produce some of these consumables from local space-based resources.Ion propulsion systems will be needed to reduce travel times to interplanetary destinations, and we will need systems to land larger payloads (up to 40 tonnes of equipment and supplies for a human mission) on planetary surfaces. These and other innovations will be needed before humans venture into deep space.However, it is the delivery of health care that is regarded as one of the most important obstacles to be overcome. Physicians,