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Radiation Risks in Perspective - Chapter 5

Mục tiêu của quản lý rủi ro là để giảm thiểu rủi ro. Điều này có thể được thực hiện bằng một trong hai kỹ thuật tránh tiếp xúc hoàn toàn hoặc khởi tố và điều khiển khác để giảm liều cho người lao động và công chúng. Trong thực tế, nó là liều của các đại lý được kiểm soát, không phải là nguy cơ chính nó. Theo đó, các giả định cơ bản trong quản lý rủi ro là giảm liều lượng dẫn đến giảm đồng thời nguy cơ. Thật không may, có rất ít bằng chứng trực. | 5 Zero or Bust The goal of risk management is to reduce risk. This can be done by either avoiding exposure altogether or instituting engineering and other controls to reduce dose to workers and the public. In practice it is the dose of the agent that is controlled not the risk itself. Accordingly the underlying assumption in risk management is that reduction of dose leads to a concomitant reduction in risk. Unfortunately there is little direct evidence to support this assumption for carcinogen exposures in occupational and environmental settings.1 In reality the number of cancers averted for a given diminution in dose cannot be observed directly because risks are very small to begin with. Instead the number of cancer deaths averted is calculated based on a theoretically determined reduction in risk. This chapter explores commonly used strategies to manage risks. Do all risks need to be managed or are some risks so small that they pose little if any health threat and can therefore effectively be ignored This chapter also explores risk characteristics that trigger management decisions. Whatever management decisions need to be made they should be based on considerations of dose rather than risk. As discussed in previous chapters measurements of risk are highly uncertain particularly at levels typically encountered in environmental and occupational settings. However we can measure small doses of radiation particularly from external sources of x- and gamma rays very accurately. Anchoring dose measurements to natural background radiation levels is a meaningful approach to dose management without incorporating risk estimation and its significant uncertainties. Management of radiation risk is complicated by fear of radiation and interestingly by our technological capacity in measuring very small radiation doses. Radiation can be measured at levels that are tiny fractions of natural background radiation levels. The view is that if we can measure very small doses then we .