Current through Register Vol. 39, No. 6, September 16, 2024
All fluoroscopic x-ray systems shall meet the following
requirements:
(1) Limitation of useful
beam
(a) The fluoroscopic tube shall not
produce x-rays unless the primary protective barrier is in position to
intercept the entire useful beam at all times.
(b) The entire cross section of the useful
beam shall be intercepted by the primary protective barrier of the fluoroscopic
image assembly at any SID.
(c)
Limitation to the Imaging Surface
(i) The
x-ray field produced by fluoroscopic equipment without image intensification
shall not extend beyond the entire visible area of the image receptor. This
requirement applies to field size during both fluoroscopic procedures and
spot-filming procedures.
(ii)
Image-intensified fluoroscopy and spot-filming shall comply with the following:
(A) During fluoroscopic or spot-filming
procedures, neither the length nor the width of the x-ray field in the plane of
the image receptor shall exceed the visible area of the image receptor by more
than three percent of the SID. The sum of the excess length and the excess
width shall be no greater than four percent of the SID.
(B) Compliance shall be determined with the
beam axis perpendicular to the image receptor. For rectangular x-ray fields
used with circular image reception, the error in alignment shall be determined
along the length and width dimensions of the x-ray field which pass through the
center of the visible area of the image receptor.
(iii) In addition to other requirements of
this Rule, equipment manufactured after the effective date of these Rules shall
comply with the following:
(A) Means shall be
provided between the source and the patient for adjustment of the x-ray field
size in the plane of the film to the size of that portion of the film which has
been selected on the spot-film selector. This adjustment shall be automatically
accomplished except when the x-ray field size in the plane of the film is
smaller than that of the selected portion of the film.
(B) It shall be possible to adjust the x-ray
field size in the plane of the film to a size smaller than the selected portion
of the film. The minimum field size at the greatest SID, shall be equal to or
less than five centimeters by five centimeters.
(C) The center of the x-ray field in the
plane of the film shall be aligned with the center of the selected portion of
the film to within two percent of the SID.
(2) X-ray production in the
fluoroscopic mode shall be controlled by a device which requires continuous
pressure by the fluoroscopist for the entire time of any exposure. When
recording serial fluoroscopic images, the fluoroscopist shall be able to
terminate the x-ray exposure(s) at any time, but means may be provided to
permit completion of any single exposure of the series in process.
(3) Entrance exposure rates shall be limited
as required in the following:
(a) Fluoroscopic
equipment shall not be operated at any combination of tube potential and
current which will result in an exposure rate in excess of ten roentgens per
minute at the point where the center of the useful beam enters the patient,
except:
(i) during recording of fluoroscopic
images; or
(ii) when provided with
optional high level control, the equipment shall not be operable at any
combination of tube potential and current which will result in an exposure rate
in excess of five roentgens per minute at the point where the center of the
beam enters the patient unless the high level control is activated. Special
means of activation of high level controls, such as additional pressure applied
continuously by the operator, shall be required to avoid accidental use. A
continuous signal audible to the fluoroscopist shall indicate that the high
level control is being employed.
(b) In addition to the other requirements of
this Rule equipment manufactured after August, 1974, which does not incorporate
an automatic exposure control (e.g., automatic brightness control or ionization
chamber control) shall not be operated at any combination of tube potential and
current which will result in an exposure rate in excess of five roentgens per
minute at the point where the center of the useful beam enters the patient
except during the recording of fluoroscopic images or when provided with an
optional high level control.
(c)
Compliance with the provisions of Item (3) of this Rule shall be determined as
follows:
(i) Movable grids and compression
devices shall be removed from the useful beam during the measurement.
(ii) If the source is below the table, the
exposure rate shall be measured one centimeter above the tabletop or
cradle.
(iii) If the source is
above the table, the exposure rate shall be measured at 30 centimeters above
the tabletop with the end of the beam-limiting device or spacer positioned as
closely as possible to the point of measurement.
(iv) In a C-arm type fluoroscope, the
exposure rate shall be measured 30 centimeters from the input surface of the
fluoroscopic imaging assembly.
(d) Periodic measurement of entrance exposure
rate limits shall comply with the following:
(i) Such measurements shall be made every two
years or after any maintenance of the system which might affect the exposure
rate.
(ii) Results of these
measurements shall be available or posted where any fluoroscopist may have
ready access to them and shall be in the record required in Rule.0603(a)(2)(B)
of this Section. Results of the measurements shall include the exposure rate,
as well as the physical factors used to determine all data; the name of the
person approved by the agency performing the measurements and the date the
measurements were performed.
(iii)
Entrance exposure rate shall be determined with the attenuation block in Rule
.0602(a) in the primary beam.
(4) Radiation transmitted through the primary
protective barrier of the fluoroscopic imaging assembly shall comply with the
following requirements:
(a) The exposure rate
resulting from transmission through the primary protective barrier with the
attenuation block in the useful beam, combined with radiation from the image
intensifier, if provided, shall not exceed two milliroentgens per hour at ten
centimeters from any accessible surface of the fluoroscopic imaging assembly
beyond the plane of the image receptor for each roentgen per minute of entrance
exposure rate.
(b) Measurements to
determine compliance with Sub-item (4)(a) of this Rule shall be in accordance
with the following:
(i) The exposure rate
resulting from transmission through the primary protective barrier combined
with radiation from the image intensifier shall be determined by measurements
averaged over an area of 100 square centimeters with no linear dimension
greater than 20 centimeters;
(ii)
If the source is below the tabletop, the measurement shall be made with the
input surface of the fluoroscopic imaging assembly, positioned 30 centimeters
above the tabletop.
(iii) If the
source is above the tabletop and the SID is variable, the measurement shall be
made with the end of the beam-limiting device or spacer as close to the
tabletop as it can be placed, provided that it shall not be closer than 30
centimeters;
(iv) Movable grids and
compression devices shall be removed from the useful beam during the
measurement;
(v) The attenuation
block shall be positioned in the useful beam ten centimeters from the point of
measurement of entrance exposure rate and between this point and the input
surface of the fluoroscopic imaging assembly.
(5) During fluoroscopy and cinefluorography,
x-ray tube potential and current shall be continuously indicated.
(6) The source-skin distance shall not be
less than:
(a) 38 centimeters on stationary
fluoroscopes,
(b) 30 centimeters on
all mobile fluoroscopes, or
(c) 20
centimeters for image intensified fluoroscopes during surgical
application.
(7)
Fluoroscopic timers shall meet the following requirements:
(a) Means shall be provided to preset the
cumulative on-time of the fluoroscopic tube. The maximum cumulative time of the
timing device shall not exceed five minutes without resetting.
(b) A signal audible to the fluoroscopist
shall indicate the completion of any preset cumulative on-time. Such signal
shall continue to sound while x-rays are produced until the timing device is
reset.
(8) Mobile
fluoroscopes, in addition to the other requirements of this Rule, shall provide
image intensification.
(9)
Scattered radiation shall be controlled in accordance with the following
requirements:
(a) A shielding device of at
least 0.25 mm lead equivalent for covering the Bucky slot during fluoroscopy
shall be provided.
(b) A shield of
at least 0.25 mm lead equivalent, such as overlapping protective drapes or
hinged or sliding panels, shall be provided to intercept scattered radiation
which would otherwise reach the fluoroscopist and others near the
machine.
(c) Upon application to
the agency with adequate justification, exceptions from Sub-items (9)(a) or
(9)(b) of this Rule may be made in some special procedures where a sterile
field will not permit the use of the normal protective barriers or where the
protective barriers would interfere with the procedures.
Authority
G.S.
104E-7;
Eff. February 1,
1980;
Amended Eff. May 1, 1993; May 1, 1992; October 1,
1980;
Transferred and Recodified from
15A NCAC
11.0605 Eff. February 1,
2015.