Regional Basic Professional Training Course in Korea

❙ 71 ❙
2. Radiation Protection
of the absorbed dose is deposited in succeeding years. Thus these quantities are not
recommended for estimating health effects or assessing the probability of deleterious
effects. However, they are useful for routine radiation protection purposes such as
assessing compliance with the annual effective dose limits and also in the design of
facilities. The unit of committed equivalent and effective dose remains the sievert. The
above quantities all relate to estimating the biologic effects of absorbed dose in the
individual.
ICRP has defined additional quantities, collective equivalent and effective dose to
estimate biologic effects in exposed groups or populations. This is achieved by
multiplying the average absorbed dose to the exposed group by the number of persons in
the group. If more than one group is involved, the total collective quantity is the sum of
the collective quantities for each group. The unit of these collective quantities is termed
the “man sievert”. These collective quantities should be thought of as representing the
total stochastic consequences to the group, but they should only be applied when the
consequences are truly proportional to both the dosimetric quantity and to the number of
people exposed. ICRP has defined other quantities such as the “dose commitment” to be
used only as a calculational tool, the ambient and direction dose equivalent to be used for
environment and area monitoring and the individual dose equivalent, penetrating and
superficial, to be used for purposes of monitoring individuals. It has also defined
probability coefficients for relating probability of stochastic effects to dosimetric
quantities. All of these are defined to aid in applying the principles of radiation protection
to both those who are occupationally exposed and to the general public. For further
information regarding these units, the reader is referred to ICRP Publications 60 and
103.[1][2]