Administrative Rules of Montana
Department 37 - PUBLIC HEALTH AND HUMAN SERVICES
Chapter 37.14 - RADIATION CONTROL
Subchapter 37.14.10 - X-Rays in the Healing Arts
Rule 37.14.1006 - FLUOROSCOPIC INSTALLATIONS
Universal Citation: MT Admin Rules 37.14.1006
Current through Register Vol. 18, September 20, 2024
(1) The equipment used in fluoroscopic installation shall be as follows:
(a) The tube housing shall be of a diagnostic
type.
(b) During fluoroscopy and
cinefluorography, the kV and the mA shall be continuously indicated.
(c) The source to skin distance shall not be
less than:
(i) 38 centimeters on stationary
fluoroscopes installed after March 28, 1980.
(ii) 35.5 centimeters on stationary
fluoroscopes which are in operation prior to March 28, 1980;
(iii) 30 centimeters on all mobile
fluoroscopes; and
(iv) 20
centimeters for image intensified fluoroscopes used for specific surgical
application. The users operating manual must provide precautionary measures to
be adhered to during the use of this device.
(d) The total filtration permanently in the
useful beam shall be at least 2.5 millimeters aluminum equivalent.
(e) The equipment shall be so constructed
that, under conditions of normal use, the entire cross section of the useful
beam is attenuated by a primary protective barrier, permanently incorporated
into the equipment and the exposure shall automatically terminate when the
barrier is removed from the useful beam.
(i)
The lead equivalent of the barrier of conventional fluoroscopes shall be at
least 1.5 millimeters for equipment capable of operating up to 100 kVp, at
least 1.8 millimeters for equipment capable of operating between 100 kVp and
125 kVp, and at least 2 millimeters for equipment capable of operating between
125 kVp and 150 kVp.
(ii) With the
fluorescent screen 14 inches (35 cm) from the panel or table top, the exposure
rate 2 inches (5 cm) beyond the viewing surface of the screen shall not exceed
30 mR/hr. for each R per minute at the table top with the screen in the useful
beam without a patient and with the fluoroscope operating at its highest
possible potential.
(iii) A
collimator shall be provided to restrict the size of the useful beam to less
than the area of the barrier. The x-ray tube and collimating system shall be
linked with the fluorescent screen assembly so that the useful beam at the
fluorescent screen is confined within the barrier irrespective of the
panel-screen distance. For all new fluoroscopic units with image intensifiers
sold in Montana after July 1, 1969, the useful beam shall be centered on the
input phosphor and during fluoroscopy or cine recording shall not exceed the
diameter of the input phosphor.
(iv) When the adjustable diaphragm is opened
to its fullest extent, an unilluminated margin shall exist at all edges of the
fluorescent screen when the screen is 14 inches (35 cm) from the panel surface
or table top or at the fixed screen position in equipment such as
orthodiascopes. In equipment used solely for image intensified fluoroscopy, the
shutter shall restrict the useful beam within the diameter of the input
phosphor.
(v) Collimators,
adjustable diaphragms and shutters shall provide the same degree of attenuation
as is required of the tube housing.
(f) The fluoroscopic exposure switch shall be
a dead-man switch type.
(g) A
shielding device of at least 0.25 millimeters lead equivalent for covering the
Bucky slot during fluoroscopy shall be provided on all new units sold in
Montana after July 1, 1969.
(h) A
shield of at least 0.25 millimeters lead equivalent such as overlapping
protective drapes or hinged or sliding panels shall be provided on all new
units sold in Montana after July 1, 1969, to intercept scattered radiation
which would otherwise reach the fluoroscopist and others near the
machine.
(i) A cumulative timing
device activated by the fluoroscope exposure switch shall be provided. It shall
indicate the passage of a predetermined period of irradiation either by an
audible signal or by temporary interruption of the irradiation when the
increment of exposure time reaches a predetermined limit not exceeding 5
minutes.
(j) Image intensification
shall always be provided on mobile fluoroscopic equipment. It shall be
impossible to operate mobile fluoroscopic equipment unless the useful beam is
intercepted by the image intensifier.
(k) Provision shall be made to intercept the
scattered x-rays from the undersurface of the table top and other structures
under the table. The shieldings shall provide the same degree of attenuation as
is required of the tube housing, with the incident angle of the useful beam
taken into consideration.
(l)
Equipment to be operated in areas where explosive gases may be used shall have
the approval of underwriters laboratory for such use.
(2) Ordinarily, only secondary protective barriers shall be required for shielding in fluoroscopic installations except for combined fluoroscopic-radiographic installations.
(3) The operating procedures for fluoroscopic installation areas are as follows:
(a) The
allowable limits for entrance exposure rates are as follows:
(i) The exposure measured at the point where
the center of the useful beam enters the patient shall not exceed 10 roentgens
per minute, except during recording of fluoroscopic images or when provided
with optional high level control.
(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 5
roentgens per minute at the point where the center of the useful beam enters
the patient unless the high level control is activated.
(A) Special means of activation of high level
controls shall be required. The high level control shall only be operable when
continuous manual activation is provided by the operator.
(b) A continuous signal audible to the
fluoroscopist shall indicate that the high level control is being
employed.
(iii) In
addition to the other requirements, equipment which does not incorporate an
automatic exposure control shall not be operable at any combination of tube
potential and current which will result in an exposure rate in excess of 5
roentgens per minute at the point where the center of the beam enters the
patient except during recording of fluoroscopic images or when provided with an
optional high level control.
(iv)
Compliance with the requirements of (a) above shall be determined as follows:
(A) Movable grids and compression devices
shall be removed from the useful beam during the measurement.
(B) If the source is below the table,
exposure rate shall be measured 1 centimeter above the table top or
cradle.
(C) If the source is above
the table, the exposure rate shall be measured at 30 centimeters above the
table top with the end of the beam-limiting device or spacer positioned as
closely as possible to the point of measurement.
(D) In a C-arm type of fluoroscope, the
exposure rate shall be measured 30 centimeters from the input surface of the
fluoroscopic imaging assembly.
(b) The fluoroscopist's eyes shall be
sufficiently dark adapted (20 minutes) for the visual task required before
commencing fluoroscopy.
(c)
Extraneous light that interferes with the fluoroscopic examination shall be
eliminated.
(d) Protective aprons
of at least 0.25 millimeters lead equivalent shall be worn in the fluoroscopy
room by each person except the patient.
(e) Only persons whose presence is necessary
shall be in the fluoroscopy room during x-ray exposures.
(f) Fluoroscopy shall not be used as a
substitute for radiography but shall be reserved for the study of dynamics or
spatial relationships or for guidance in spot-film recording of critical
details.
(g) Special precautions,
consistent with clinical needs, shall be taken to minimize exposure of the
gonads of potentially procreative patients and exposure of the embryo or fetus
in patients known to be or suspected of being pregnant.
(h) Notwithstanding ARM
37.14.721, personnel monitoring is
required for each individual who enters a controlled area.
Sec. 75-3-201 and 75-3-202, MCA; IMP, Sec. 75-3-201 and 75-3-202, MCA;
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