Current through Register Vol. 24-18, September 15, 2024
(1) The use of a
special purpose X-ray machine designed and used solely for mammography is
required. Exempted from this requirement shall be X-ray equipment using
xerography for evaluation of breast implant integrity.
(2) All mammographic calibration, evaluation,
service, and quality control actions shall be documented in writing and
maintained at the facility for a three-year period. Records must be easily
accessible to operators of these X-ray units.
(3) All tests requiring the use of a breast
phantom shall employ a phantom similar to or identical to the one required by
the American College of Radiology for its mammography accreditation
program.
(4) Machine requirements:
(a) Mammography X-ray machines must be
evaluated upon any major component change and on a yearly basis by a qualified
medical physicist. Evaluation shall document (but is not limited to) half-value
layer (HVL), kVP accuracy, reproducibility, timer accuracy, resolution achieved
with film in use at the facility, focal spot size, mA linearity, light versus
X-ray field alignment, and patient exposures (glandular tissue dose) following
the measurement protocol in NCRP Report No. 85 (using a breast phantom). This
requirement shall include initial acceptance testing upon the X-ray system's
installation prior to human use.
(b) The half-value layer (HVL) for
film/screen mammography shall be between the values of measured kVp/100 and
measured kVp/100 + 0.1 millimeters aluminum. The half-value layer for
xerography shall be at least 1.2 mm but no greater than 1.6 mm of aluminum as
measured at 50 kVP. The HVL shall include the contribution to filtration made
by the compression device.
(c)
Exposure reproducibility: Manual techniques. See WAC
246-225-090.
(d) Exposure reproducibility: Photo-timed
techniques. Mammographic systems in the AEC mode shall be able to maintain
constant film density to within an optical density of ± 0.3 of the
average optical density over the range of clinically used kVps, using BR-12 or
other breast equivalent material phantom thicknesses of 2 centimeters to 6
centimeters. If the facility has established a technique chart that utilizes
varying technical factors for different breast thicknesses, those adjustments
in technique may be used when complying with this requirement.
(e) Radiographic timers. See WAC
246-225-070.
(f) kVP accuracy: The kVP accuracy published
by the X-ray machine manufacturer shall be maintained at the specified level.
For determination of actual versus indicated kVP, the manufacturer's
recommendations for testing shall be followed.
(g) mA linearity. See WAC
246-225-040(10).
(h) All special purpose X-ray machines
designed solely for mammography and installed after January 1, 1992, shall be
equipped with a milli-ampere-second (mAs) read-out device, registering after
each phototimed exposure. Alternatively, a means of determining mAs after each
exposure shall be provided.
(i)
Beam limitation:
(i) Mammographic systems
shall be provided with means to limit the useful beam such that the X-ray field
at the plane of the image receptor does not extend beyond any edge of the image
receptor at any designed SID except the edge of the image receptor designed to
be adjacent to the chest wall where the X-ray field may not extend beyond such
edge by more than two percent of the SID.
(ii) Beam limiting devices consisting of an
assortment of fixed, removable cones sufficient to meet the requirement for
each combination of image receptor size and SID for which the unit is designed
shall have clear and permanent markings to indicate the image receptor size and
SID for which it is designed.
(iii)
When the beam limiting device and image receptor support device are designed to
be used to immobilize the breast during a mammographic procedure and the SID
may vary, the SID indication specified in WAC
246-225-060(4)(c)(i) and
(ii) shall be the maximum SID for which the
beam limiting device or aperture is designed.
(iv) In the absence of a visually defined
X-ray field each image receptor support shall have clear and permanent markings
to indicate the maximum image receptor size for which it is designed.
(j) The combination of
source-to-image distance, magnification, and focal spot size shall result in a
radiographic resolution of at least 12 line pairs per millimeter. This standard
applies to the mammographic, single emulsion film being used at the
facility.
(k) The X-ray machine
shall be equipped with a means of immobilizing and compressing the breast with
a force of at least twenty-five pounds but no greater than forty
pounds.
(l) Dedicated mammographic
X-ray units are exempted from the requirements of WAC
246-225-030(5)(b)(i) provided that appropriate operator shielding
is employed (as defined by NCRP Report 49).
(m)
Transmission limit for image
receptor supporting devices used for mammography. For X-ray systems
manufactured after September 5, 1978, which are designed only for mammography,
the transmission of the primary beam through any image receptor support
provided with the system shall be limited such that the exposure 5 centimeters
from any accessible surface beyond the plane of the image receptor supporting
device does not exceed 25.8 nanocoulombs per kilogram (0.1 milliroentgen) for
each activation of the tube. Exposure shall be measured with the system
operated at the minimum SID for which it is designed. Compliance shall be
determined at the maximum rated peak tube potential for the system and at the
maximum rated product of tube current and exposure time (mAs) for that peak
tube potential. Compliance shall be determined by measurements averaged over an
area of 100 square centimeters with no linear dimension greater than 20
centimeters.
(n) Maximum glandular
doses. Glandular tissue dose for a cranio-caudal view of a 4.5 cm compressed
breast using dose calculation methods found in NCRP Report # 85 shall not
exceed the following:
(5) A quality
control program shall be written and implemented for all mammographic
facilities. This shall include (but shall not be limited to) tests performed,
testing frequency, testing protocol, control limits for each test, corrective
actions taken, and equipment maintenance/service. Program requirements include:
(a) Daily tests:
Film processor control charts using a
sensitometric/densitometric based measurement system shall be required for each
day the mammographic machine is in operation. Single emulsion mammographic film
shall be used for this evaluation. The sensitometer shall be one with a 21-step
optical attenuator.
Parameters in daily film processor tests shall
include:
(i) Speed index
(mid-density):
Control limits ± 0.15 optical density
(ii) Contrast index (density
difference):
Control limits ± 0.15 optical density
(iii) Base + fog:
Maximum density shall not exceed 0.20 optical density.
(iv) Solution temperatures, using
a digital thermometer that reads out in tenths of a degree and that is accurate
to within ± 0.5°F.
Control limits ± 1.0 F
(b) Monthly tests:
(i) Chemical replenishment rates.
(ii) Image quality evaluation. The
mammographic system shall be capable of providing an image of a 0.75 mm fiber,
0.32 mm speck group, and a 0.75 mm mass from an ACR, or equivalent, phantom on
the standard mammographic image receptor system in use at the facility.
Mammograms shall not be taken on patients if this minimum is not met. Any
fibers, speck groups or masses larger than those specified shall also be
imaged.
(c) Quarterly
tests:
(i) Film/screen contact for all
cassettes, using a 40-mesh copper screen.
(ii) Analyses of reject/repeat
films.
(iii) Fixer retention in
processed film.
(d)
Semi-annual tests:
(i) Darkroom
fog.
(ii) Compression device
force.
(e) Yearly tests:
See WAC 246-225-160(4)(a).
(f) Cassette screens must be cleaned at least
weekly.
(g) Records shall be
maintained for quality control test equipment which requires calibration, and
such calibrations shall be performed in accordance with recommendations of the
manufacturer of the test equipment.
(h) Film processing. See WAC
246-225-150. A film processor
that cannot be consistently made to operate within the control limits specified
in (a) of this subsection shall not be used to process mammographic
films.
(6) Operator
competency:
(a) A mammographic machine
operator shall be licensed, certified, or registered by the department as
either:
(i) A health care practitioner,
licensed under
Title
18 RCW, if performing
mammography is within the person's authorized scope of practice; or
(ii) A diagnostic radiologic technologist
certified in accordance with
chapter
18.84 RCW; or
(iii) An X-ray technician registered in
accordance with
chapter
18.84 RCW, with two or
more years' experience in performing mammography and satisfactory completion of
at least sixteen hours of training in mammographic positioning, mammographic
quality assurance, and/or other related areas subject to approval by the
department.
(b) A
mammographic machine operator shall complete the equivalent of at least eight
hours of training every twelve months covering such areas as mammographic
positioning, mammographic quality assurance and other related areas subject to
approval by the department.
(c) A
mammographic machine operator shall meet the requirements of WAC
246-225-020(2)(b) and
246-225-99920.
(7) Masking devices shall be made
available to block extraneous light from the viewer's eye when the illuminated
surface of the viewbox is larger than the exposed area on the film.
(8) Additional requirement for mobile
mammography services:
The daily film processor performance testing required in
subsection (5)(a) of this section shall apply to all film processors used by
the mobile service. No processor shall be used unless it meets the control
limits specified by subsection (5)(a)(i) through (iv) of this
section.
Statutory Authority:
RCW
70.98.050. 94-01-073, § 246-225-160,
filed 12/9/93, effective 1/9/94; 92-05-011 (Order 240), § 246-225-160,
filed 2/7/92, effective 3/9/92.
