| (i) Each registrant shall conduct operations so that:
(I) the total effective dose equivalent to individual
members of the public from exposure to radiation from radiation machines
does not exceed 0.5 rem (5 millisieverts) in a year, exclusive of
the dose contribution from background radiation, exposure of patients
to radiation for medical diagnosis or therapy, or to voluntary participation
in medical research programs; and
(II) the dose in any unrestricted area from external
sources does not exceed 0.002 rem (0.02 millisieverts) 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.
(C) Occupational doses from other sources of radiation.
Individuals who receive occupational doses from sources of radiation
other than dental radiation machines may be required to comply with
the requirements of §289.231(n) and (q) - (s) of this title.
(D) Instructions to workers. The registrant shall provide
instructions to radiation workers before beginning initial work in
restricted areas. These instructions shall include the following:
(i) precautions or procedures to minimize exposure;
(ii) the applicable provisions of agency requirements
and certificates of registration for the protection of personnel from
exposures to radiation occurring in such areas; and
(iii) the radiation worker's responsibility to report
promptly to the registrant any condition that may constitute, lead
to, or cause a violation of agency requirements or certificate of
registration conditions, or unnecessary exposure to radiation.
(4) Facility requirements.
(A) Caution signs. Unless otherwise authorized by the
agency, the standard radiation symbol prescribed shall use the colors
magenta, purple or black on yellow background. The standard radiation
symbol prescribed is the three-bladed design as follows:
Attached Graphic
(i) the cross-hatched area of the symbol is to be magenta,
purple, or black; and
(ii) the background of the symbol is to be yellow.
(B) Posting of notices to workers.
(i) Each registrant shall post current copies of the
following documents:
(I) RC Form 232-1, "Notice to Employees," or an equivalent
document containing at least the same wording as RC Form 232-1; and
Attached Graphic
(II) a notice that describes the following documents
and states where the documents may be examined:
(-a-) a copy of this section;
(-b-) the certificate of registration and conditions
or documents incorporated into the certificate of registration by
reference and amendments thereto;
(-c-) the operating procedures applicable to work under
the certificate of registration; and
(-d-) any notice of violation, if applicable, involving
radiological working conditions, or order issued in accordance with
subsections (b) and (l)(3) of this section and documentation of the
corrections of any violations.
(ii) Documents, notices, or forms posted in accordance
with this subsection shall:
(I) appear in an area visible to all workers to permit
individuals engaged in work under the certificate of registration
to observe the documents on the way to or from any particular work
location to which the document applies;
(II) be conspicuous; and
(III) be replaced if defaced or altered.
(C) Posting requirements. The registrant shall post
each radiation area with a conspicuous sign or signs bearing the radiation
symbol and the words "CAUTION, RADIATION AREA."
(D) Exceptions to posting requirements. Registrants
are exempt from the posting of the radiation area requirements in
subparagraph (C) of this paragraph if the operator has continuous
surveillance and access control of the radiation area.
(E) Security and control of radiation machines.
(i) The registrant shall establish a protocol to ensure
radiation machines are secure from unauthorized removal.
(ii) The registrant shall use devices and administrative
procedures to prevent unauthorized use of radiation machines.
(iii) Any person using hand-held dental radiation machines
shall ensure proper storage of the unit to include:
(I) securing the unit against theft or unauthorized
use; and
(II) storing the unit in locked cabinets, storage rooms
or work areas when not under immediate supervision of authorized users.
(5) Radiation machine requirements.
(A) Technique chart.
(i) A technique chart relevant to the particular radiation
machine shall be provided or electronically displayed near the control
panel and used by all operators.
(ii) Technique and exposure indicators.
(I) The technique factors to be used during an exposure
shall be indicated before the exposure begins except:
(-a-) when automatic exposure controls are used, in
which case the technique factors that are set before the exposure
shall be indicated; or
(-b-) unless prevented by the design of the certified
radiation machine.
(II) On radiation machines having fixed technique factors,
the requirement of subclause (I) of this clause may be met by permanent
markings.
(III) The x-ray control shall provide visual indication
of the production of x-rays. In addition, a signal audible to the
operator shall indicate that the exposure has terminated.
(IV) The indicated technique factors shall be accurate
to within manufacturer's specifications. If these specifications are
not available from the manufacturer, the factors shall be accurate
to within plus or minus 10% of the indicated setting.
(B) Labeling radiation machines. Each registrant shall
ensure that each radiation machine is labeled in a conspicuous manner
that cautions individuals that radiation is produced when it is energized.
This label shall be affixed in a clearly visible location on the face
of the radiation machine.
(C) Mechanical support of tube head. The tube housing
assembly shall be adjusted to remain stable during an exposure unless
tube housing movement is a designed function of the radiation machine.
(D) Battery charge indicator. On battery-powered x-ray
generators, visual means shall be provided on the control panel to
indicate whether the battery is in a state of charge adequate for
proper operation.
(E) Beam quality. The following requirements apply
to beam quality.
(i) Half-value layer.
(I) The half-value layer of the useful beam for a given
x-ray tube potential shall not be less than the values shown in the
following table. If it is necessary to determine such half-value layer
at an x-ray tube potential that is not listed in the table, linear
interpolation may be made.
Attached Graphic
(II) For capacitor energy storage equipment, compliance
with the requirements of this subparagraph shall be determined with
the maximum quantity of charge per exposure.
(ii) Filtration controls.
(I) For radiation machines that have variable kilovolt
peak and variable filtration for the useful beam, a device shall link
the kilovolt peak selector with the filters and shall prevent an exposure
unless the minimum amount of filtration required by clause (i) of
this subparagraph is in the useful beam for the given kilovolt peak
that has been selected.
(II) Any other radiation machine having removable filters
shall be required to have the minimum amount of filtration as required
by clause (i)(I) of this subparagraph permanently located in the useful
beam during each exposure.
(F) Multiple tubes. Where two or more radiographic
tubes are controlled by one exposure switch, the tube or tubes that
have been selected shall be clearly indicated before initiation of
the exposure. This indication shall be both on the x-ray control panel
and at or near the tube housing assembly that has been selected.
(G) X-ray control. An x-ray control shall be incorporated
into each radiation machine such that an exposure can be terminated
by the operator at any time, except for exposures of 0.5 second or
less. The exposure switch shall be of the continuous pressure type.
Cont'd... |
