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IMPACT ON PEOPLE AND THE ENVIRONMENT
Dose

DEFINITIONS OF THE LEVELS

 

As we look at the criteria you will see that, as well as depending on the size of the dose, the definitions of the levels also depend on:

who
what
how many

who gets the dose

Workers

any person who works, whether full time, part time, or temporarily, for an employer and who has recognized rights and duties in relation to occupational radiation protection.

Public

members of the public—in a general sense, any individual in the population except, for protection and safety purposes, when subject to occupational or medical exposure.

what are the effects of the exposure?

Deterministic:

  • Usually the result of high doses received in a short time
  • Damage depends on absorbed dose
  • Threshold exists
  • Many cells die or have function altered

examples:
cataract, erythema, infertility

Stochastic:

  • Probability of occurrence, not severity, depends on absorbed dose
  • Threshold assumed not to exist

examples:
radiation-induced cancers, hereditary effects

N.B. Smaller doses only cause stochastic effects

how many people are exposed?

Define a minimum rating appropriate to a single person receiving a defined dose level:

Then increase it by 1 or 2 levels depending on how many people are exposed.

We’ll go into more detail shortly...