Current through Register 1531, September 27, 2024
(A) The
licensee or registrant shall control the occupational dose to individual
adults, except for planned special exposures pursuant to
105 CMR
120.216, to the following dose limits:
(1) An annual limit, which is the more
limiting of
(a) the total effective dose
equivalent being equal to .05 sievert (five rems); or
(b) the sum of the deep dose equivalent and
the committed dose equivalent to any individual organ or tissue other than the
lens of the eye being equal to 0.5 sievert (50 rems).
(2) The annual limits to the lens of the eye,
to the skin, and to the extremities which are:
(a) a lens dose equivalent of 0.15 sievert
(15 rems); and
(b) a shallow dose
equivalent of 0.5 sievert (50 rems) to the skin of the whole body or to the
skin of any extremity.
(B) Doses received in excess of the annual
limits, including doses received during accidents, emergencies, and planned
special exposures, shall be subtracted from the limits for planned special
exposures that the individual may receive during the current year and during
the individual's lifetime. See
105 CMR 120.216(E)(1)
and (2).
(C)
(1) When
the external exposure is determined by measurement with an external personal
monitoring device, the deep-dose equivalent must be used in place of the
effective dose equivalent, unless the effective dose equivalent is determined
by a dosimetry method approved by the Agency. The assigned deep-dose equivalent
must be for the part of the body receiving the highest exposure. The assigned
shallow-dose equivalent must be the dose averaged over the contiguous ten
square centimeters of skin receiving the highest exposure. The deep-dose
equivalent, lens-dose equivalent, and shallow-dose equivalent may be assessed
from surveys or other radiation measurements for the purpose of demonstrating
compliance with the occupational dose limits, if the individual monitoring
device was not in the region of highest potential exposure, or the results of
individual monitoring are unavailable;
(2) When a protective apron is worn while
working medical fluoroscopic equipment and monitoring is conducted as specified
in
105
CMR 120.226(A)(5), the
effective dose equivalent for external radiation shall be determined as
follows:
(a) When only one individual
monitoring device is used and it is located at the neck (collar) outside the
protective apron, the reported deep dose equivalent shall be the effective dose
equivalent for external radiation; or
(b) When only one individual monitoring
device is used and it is located at the neck (collar) outside the protective
apron, and the reported dose exceeds 25% of the limit specified in 105 CMR
120.211(A), the reported deep dose equivalent value multiplied by 0.3 shall be
the effective dose equivalent for external radiation; or
(c) When individual monitoring devices are
worn, both under the protective apron at the waist and outside the protective
apron at the neck, the effective dose equivalent for external radiation shall
be assigned the value of the sum of the deep dose equivalent reported for the
individual monitoring device located at the waist under the protective apron
multiplied by 1.5 and the deep dose equivalent reported for the individual
monitoring device located at the neck outside the protective apron multiplied
by 0.04.
(D)
Derived air concentration (DAC) and annual limit on intake (ALI) values are
specified in
105
CMR 120.296: Appendix B,
Table I and may be used to determine the individual's dose and to demonstrate
compliance with the occupational dose limits. See
105 CMR
120.267.
(E) In addition to the annual dose limits,
the licensee shall limit the soluble uranium intake by an individual to ten
milligrams in a week in consideration of chemical toxicity.
See footnote 3 of
105
CMR 120.296: Appendix
B.
(F) The licensee or
registrant shall reduce the dose that an individual may be allowed to receive
in the current year by the amount of occupational dose received while employed
by any other person during the current year. See
105 CMR
120.265(E).
