Operating Manual

19
Radiation hazards, measuring-
and recording instruments
19.1 The effects of radiation on the human body
The human body is constantly exposed to natural radiation (e.g. from space, the soil and
buildings), also known as background radiation. All ionising radiation, whether electro-
magnetic (gamma-γ) or corpuscular (particles in the form of alpha-α or beta-β), and neu-
trons, are harmful to the human body. The unit “absorbed dose” (D) defines the effect of
radiation on various substances. D is the absorbed dose in J/kg or Gray (Gy).
The biological damage done by the various types of ionising radiation, α, β, γ or fast neu-
trons, differs and depends on the quality factor (Q). The unit to which the damage quality
factor is applied is the equivalent dose H.
The equivalent dose is the product of absorbed dose (D) and quality factor (Q), so the equi-
valent dose is calculated as H = D
.
Q [Sv], (Sv = Sievert).
The Q factors for various types of radiation are indicated in table 1-19.
19.2 Responsibilities
The client
It is the client’s responsibility to consider possible alternatives before utilising ionising radi-
ation. Considering its purpose, the decision to use ionising radiation can only be justified
when the radiation hazard remains at an acceptable level.
The radiographer
It is primarily the radiographer’s responsibility to protect himself and others from exposure
to radiation.
Type of radiation Quality factor (Q)
X and gamma radiation (γ)1
Beta radiation (β)1
Alpha radiation (α)20
Fast neutrons 10
Table 1-19. Q-factors for various types of radiation
On stream image of insulated pipe CR-image of a weld
see acknowledgements*
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