Current through Register Vol. 24-18, September 15, 2024
(1) Before construction, the floor plans and
equipment arrangement of medical installations (new or modifications of
existing installations) utilizing X rays for diagnostic or therapeutic purposes
shall be submitted to:
(a) A qualified expert
for determination of shielding requirements using National Council on Radiation
Protection and Measurements (NCRP) Report No. 147, available at the NCRP web
site at https://www.ncrppublications.org, or equivalent; and
(b) The department for subsequent review.
Review shall not imply approval.
(2) The review of such plans shall not
preclude the requirement of additional modifications should a subsequent
analysis of operating conditions indicate the possibility of an individual
receiving a dose in excess of the limits required under WAC
246-221-010,
246-221-050, and
246-221-060.
(3)Diagnostic veterinary, podiatric, and
dental facilities shall be exempt from submitting shielding calculations and
floor plans.
(4)In order for the
department to provide an evaluation, technical advice, and official review of
the shielding requirements for a medical radiation installation, a floor plan
drawn to scale and the following data are required:
(a)The normal location of the X-ray tube,
along with an indication of anode-cathode orientation to the cassette
holders;
(b)The limits of the tube
travel;
(c)The directions in which
the tube is pointed;
(d)Window
locations;
(e)The location of the
control booth or operator's position;
(f)The exposure switch location;
(g)The position of the viewing window, if
any;
(h) The composition and
thickness of the walls;
(i) If more
than one story, the height floor-to-floor;
(j) If more than one story, the composition
and thickness of materials in the ceiling or floor;
(k) The make and model of the X-ray
machine;
(l) The maximum kVp and
mA;
(m) The types of examinations
or treatments (for example, chest, spine, general X-ray, or therapy);
(n) The identification and occupancy of areas
adjacent to the X-ray room;
(o) The
anticipated X-ray workload expressed in number of patients and exposures per
week including:
(i) Technique factors used,
or milliampere-seconds or milliampere-minutes per week; and
(ii) Estimates of the percentage of the
workload expected to occur for a particular beam direction.
(5)For new and modified
installations only, the following are minimum design requirements for medical
X-ray machine operator booths. These requirements do not apply to dental,
podiatry, and veterinary installations. See subsections (6) and (7) of this
section for dental panoramic and cephalo-metric requirements.
(a) The operator shall be allotted 0.7 sq.
meters (7.5 sq. ft.) or more of unobstructed floor space in the X-ray booths.
(i) The 0.7 sq. meters (7.5 sq. ft.) of
minimum space specified under subsection (5)(a) of this section shall be a
geometric configuration where no dimension is less than 61.0 centimeters (2.0
ft.).
(ii) The allotted space shall
exclude an encumbrance by the console, such as an overhang, cables, or other
similar encroachment.
(iii) An
extension of a straight line drawn between any point on the edge of the booth
shielding and the nearest vertical edge of a vertical cassette holder, corner
of the examination table, or any part of the tube housing assembly shall not
impinge on the unobstructed space.
(iv) The booth walls shall be 2.1 meters (7.0
ft.) or more and shall be permanently fixed to the floor or other structure as
may be necessary.
(v) When a door
or moveable panel is used as the integral part of the booth structure, it must
have a permissive device which will prevent an exposure when the door or panel
is not closed.
(b)
Switch placement. The operator's switch for the radiographic machine shall be
fixed within the booth. The switch shall:
(i)
Be at least 102 centimeters (forty inches) inside the protected area;
and
(ii) Allow the operator to use
the available viewing windows.
(c)Viewing system requirements.
(i) Each booth shall have at least one
viewing device which shall:
(A)Be placed so
the operator can view the patient during exposure; and
(B)Be placed so the operator can have full
view of the entries into the room.
(ii) When the viewing system is a window, the
following requirements also apply:
(A)The
window shall have a visible area of 930 square centimeters (1.0 square foot) or
more; and
(B) The glass shall have
the same lead equivalence or more as that required in the booth's wall where
the glass is mounted.
(iii) When the viewing system is by mirrors,
the mirrors shall be located to accomplish the general requirements under
subdivision (i) of this subsection.
(iv) When the viewing system is by electronic
means (for example, TV):
(A)The camera shall
be located to accomplish the general requirements under subdivision (i) of this
subsection; and
(B) There shall be
an alternate viewing system as a backup for electronic failure.
(d)New or modified
facilities shall maintain a copy of the floor plan and shielding calculations
required under subsection (1) of this section.
(6)Dimensions of primary beam shielding shall
exceed the largest possible beam size by 30.5 centimeters (one foot) or more in
every direction. Cephalometric primary beam shielding shall be deemed adequate
if, for a maximum workload of twenty films a week, two-pound lead is installed
(for occupied areas).
(7) A viewing
device shall be present in dental panoramic and cephalometric X-ray
installations, so the requirements of subsection (5)(c) of this section are
met.
Statutory Authority:
RCW
70.98.050. 94-01-073, § 246-225-030,
filed 12/9/93, effective 1/9/94. Statutory Authority:
RCW
70.98.050 and
70.98.080. 91-15-083 (Order 183),
§ 246-225-030, filed 7/23/91, effective 8/23/91. Statutory Authority:
RCW
43.70.040. 91-02-049 (Order 121), recodified
as § 246-225-030, filed 12/27/90, effective 1/31/91. Statutory Authority:
RCW
70.98.080. 87-01-031 (Order 2450), §
402-28-032, filed 12/11/86; 83-19-050 (Order 2026), § 402-28-032, filed
9/16/83; Order 1084, § 402-28-032, filed 1/14/76. Formerly WAC 402-28-030
(part).
