| (-c-) The dose equivalent to an embryo/fetus shall
be taken as the dose equivalent that is most representative of the
dose equivalent to the embryo/fetus from external radiation, that
is, in the mother's lower torso region.
(-d-) If multiple measurements have been made, assignment
of the deep dose equivalent for the declared pregnant woman from the
individual monitoring device that is most representative of the dose
equivalent to the embryo/fetus shall be the dose equivalent to the
embryo/fetus. Assignment of the highest dose equivalent for the declared
pregnant woman to the embryo/fetus is not required unless that dose
is also the most representative dose equivalent for the region of
the embryo/fetus.
(-e-) If multiple measurements have not been made,
assignment of the highest dose equivalent for the declared pregnant
woman shall be the to the embryo/fetus.
(ii) The assigned dose equivalent shall be for the
portion of the body receiving the highest exposure. The assigned shallow
dose equivalent shall be the dose averaged over the contiguous 10
cm2 of skin receiving the highest exposure.
(iii) When a protective apron is worn while working
with fluoroscopic radiation machines used for clinical diagnostic
or research purposes, the effective dose equivalent for external radiation
shall be determined as follows:
(I) 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
(EDE) for external radiation; or
(II) 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 percent of the limit specified
in clause (i) of this subparagraph, the reported deep dose equivalent
value multiplied by 0.3 shall be the EDE for external radiation; or
(III) when individual monitoring devices are worn,
both under the protective apron at the waist and outside the protective
apron at the neck (collar), the EDE 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 (collar)
outside the protective apron multiplied by 0.04.
(iv) The deep dose equivalent, lens dose equivalent,
and shallow dose equivalent may be assessed from surveys or 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.
(v) The registrant shall reduce the dose that an individual
may be allowed to receive in the current year by the amount of occupational
dose received from radiation machines or radioactive materials while
employed by any other person. See subparagraph (F)(iv) of this paragraph.
(B) Conditions requiring individual monitoring of occupational
dose. Each registrant shall monitor exposures from radiation machines
at levels sufficient to demonstrate compliance with the occupational
dose limits of this section. As a minimum, each registrant shall monitor
occupational exposure to radiation from radiation machines and shall
supply and require the use of individual monitoring devices by:
(i) adults likely to receive, in one year from sources
external to the body, a dose in excess of 10 percent of the limits
in subparagraph (A)(i) of this paragraph;
(ii) minors likely to receive, in one year from radiation
machines external to the body, a deep dose equivalent in excess of
0.1 rem (1 mSv), a lens dose equivalent in excess of 0.15 rem (1.5
mSv), or a shallow dose equivalent to the skin of the whole body or
to the skin of any extremities in excess of 0.5 rem (5 mSv);
(iii) declared pregnant women likely to receive during
the entire pregnancy, from radiation machines external to the body,
a deep dose equivalent in excess of 0.1 rem (1 mSv); and
(iv) individuals entering a high or very high radiation
area.
(C) Dose limits for individual members of the public.
(i) Each registrant shall conduct operations so that:
(I) the TEDE to individual members of the public from
exposure to radiation from radiation machines does not exceed 0.5
rem (5 mSv) in a year, exclusive of the dose contribution from background
radiation, exposure of animals to radiation for the purpose of medical
diagnosis or therapy, or to voluntary participation in medical research
programs; and
(II) the dose in any unrestricted area from registered
external sources does not exceed 0.002 rem (0.02 mSv) in any one hour.
(ii) If the registrant permits members of the public
to have access to restricted areas, the limits for members of the
public continue to apply to those individuals.
(iii) The agency may impose additional restrictions
on radiation levels in unrestricted areas in order to restrict the
collective dose.
(iv) The registrant shall ensure that in facilities
utilizing both radiation producing machines and radioactive materials,
the TEDE to an individual member of the public shall not exceed 0.1
rem (1 mSv) in one year.
(D) Compliance with dose limits for individual members
of the public.
(i) The registrant shall make or cause to be made surveys
of radiation levels in unrestricted areas to demonstrate compliance
with the dose limits for individual members of the public as required
in subparagraph (C) of this paragraph.
(ii) A registrant shall show compliance with the annual
dose limit in subparagraph (C) of this paragraph by demonstrating
by measurement or calculation that the TEDE to the individual likely
to receive the highest dose from the registered operation does not
exceed the annual dose limit.
(iii) Registrants exempt from individual monitoring
requirements in accordance with subparagraph (B) of this paragraph
are exempt from the requirements of clauses (i) and (ii) of this subparagraph.
(E) Location and use of individual monitoring devices.
(i) Each registrant shall ensure that individuals who
are required to monitor occupational doses in accordance with subparagraph
(B) of this paragraph wear and use individual monitoring devices as
follows.
(I) An individual monitoring device shall be assigned
to and worn by only one individual.
(II) An individual monitoring device used for monitoring
the dose to the whole body shall be worn at the unshielded location
of the whole body likely to receive the highest exposure. When a protective
apron is worn, the location of the individual monitoring device shall
be worn outside of the protective apron.
(III) If an additional individual monitoring device
is used for monitoring the dose to an embryo/fetus of a declared pregnant
woman, in accordance with subparagraph (B)(iii) of this paragraph,
it shall be located at the waist under any protective apron being
worn by the woman.
(IV) An individual monitoring device used for monitoring
the lens dose equivalent, to demonstrate compliance with subparagraph
(A)(i)(II)(-a-) of this paragraph, shall be located at the neck (collar)
or at a location closer to the eye, outside any protective apron being
worn by the monitored individual.
(V) An individual monitoring device used for monitoring
the dose to the extremities, to demonstrate compliance with subparagraph
(A)(i)(II)(-b-) of this paragraph, shall be worn on the extremity
likely to receive the highest exposure. Each individual monitoring
device, to the extent practicable, shall be oriented to measure the
highest dose to the extremity being monitored.
(ii) Each registrant shall ensure that individual monitoring
devices are returned to the dosimetry processor for proper processing.
(iii) Each registrant shall ensure that adequate precautions
are taken to prevent a deceptive exposure of an individual monitoring
device.
(F) Determination of occupational dose for the current
year.
(i) For each individual who is likely to receive, in
a year, an occupational dose requiring monitoring in accordance with
subparagraph (B) of this paragraph, the registrant shall determine
the occupational radiation dose received during the current year.
Occupational dose includes doses received from exposure to registered/licensed
or unregistered/unlicensed sources of radiation as defined in subsection
(d) of this section.
(ii) In complying with the requirements of clause (i)
of this subparagraph, a registrant may:
Cont'd... |
