Current through Register Vol. 39, No. 6, September 16, 2024
(a) In addition
to the provisions of Rules.0603 and.0605 of this Section, the requirements of
this Rule apply to x-ray equipment and associated facilities used for dental
radiography. Criteria for extraoral dental radiographic systems are covered in
Rule.0606 of this Section.
(b)
X-ray systems designed for use with an intraoral image receptor shall be
provided with means to limit source-skin distance to not less than:
(1) 18 centimeters, if operated above 50
kilovolts peak; or
(2) ten
centimeters, if operated at or below 50 kilovolts peak.
(c) The size of the direct radiation beam
shall be limited in accordance with the following rules:
(1) Radiographic systems designed for use
with an intraoral image receptor shall be provided with means to limit the
x-ray beam such that:
(A) If the source-skin
distance (SSD) is 18 centimeters or more, the x-ray field at the SSD shall be
containable in a circle having a diameter of no more than seven centimeters;
and
(B) If the SSD is less than 18
centimeters, the x-ray field at the SSD shall be containable in a circle having
a diameter of no more than six centimeters.
(2) Effective February 1, 1981, equipment
manufactured prior to August 1974 shall be equipped with a lead line open
position indicating device with at least 0.79 mm lead.
(d) The timing device shall comply with the
following requirements:
(1) Termination of the
exposure after a preset interval;
(2) Termination of exposure shall cause
automatic resetting of the timer to its initial setting or to zero;
(3) It shall not be possible to make an
exposure when the timer is set to a zero or "off" position if either position
is provided; and
(4) When four
timer tests are performed at identical timer settings equal to five seconds or
less, the average time period (T) shall be greater than five times the
difference between the maximum period (Tmax) and the minimum period (Tmin) in
accordance with the formula:
T > 5(Tmax- Tmin)
(5) Effective February 1, 1983, intraoral
dental radiographic systems shall be equipped with an electronic
timer.
(6) Timer accuracy
(A) For indicated values of 0.10 seconds and
above, the measured value shall be within plus or minus 15 percent of the
indicated values for equipment manufactured before August 1, 1974.
(B) For equipment manufactured after August
1, 1974, the deviation of measured values from indicated values shall not
exceed the limits specified for that system by its manufacturer.
(e) The exposure switch
shall comply with the following requirements:
(1) A control shall be incorporated into each
x-ray system such that an exposure can be terminated at any time, except for
exposures of one-half second or less.
(2) Each x-ray control shall be located in
such a way as to meet the following criteria:
(A) For stationary x-ray systems installed
after the effective date of this Rule, the exposure switch shall be permanently
mounted in a protected area (e.g., corridor outside the room) so that the
operator is required to remain in that protected area during the entire
exposure.
(B) For stationary x-ray
systems without a protected area and installed before the effective date of
this Rule, the exposure switch shall be such that the operator shall stand at
least six feet away from the tube and out of the direct beam.
(C) For mobile and portable x-ray systems the
switch shall meet the requirements of Part (e)(2)(B) of this Rule.
(3) For equipment manufactured
after August 1, 1974, the x-ray control shall provide visual indication
observable at or from the operator's protected position whenever x-rays are
produced. In addition, a signal audible to the operator shall indicate that the
exposure has terminated.
(f) The exposure produced shall be
reproducible to within the following criteria:
When all technique factors are held constant, the coefficient
of variation shall not exceed 0.10. This shall be deemed to be met if, when
four exposures at identical technique factors are made, the value of the
average exposure (E) is greater than five times the difference between the
maximum exposure (Emax) and the minimum exposure (Emin) in accordance with the
formula:
E > 5(Emax- Emin)
(g) Patient and film holding devices shall be
used when the techniques permit.
(h) Neither the tube housing nor the position
indicating device shall be hand-held during an exposure.
(i) Dental fluoroscopy without image
intensification shall not be used.
(j) Structural shielding
(1) All wall, floor and ceiling areas shall
have protective barriers sufficient to meet the requirements of Rules.1604 and
.1611 of this Chapter.
(2) When
intraoral x-ray systems are installed in adjacent rooms or areas, protective
barriers as specified in Subparagraph (j)(1) of this Rule shall be provided
between the rooms or areas.
Authority
G.S.
104E-7;
Eff. February 1,
1980;
Amended Eff. January 1, 1994; October 1, 1980;
Transferred and Recodified from
15A NCAC
11 .0607 Eff. February 1,
2015.
