Louisiana Administrative Code
Title 33 - ENVIRONMENTAL QUALITY
Part XV - Radiation Protection
Chapter 6 - X-Rays in the Healing Arts
Section XV-606 - Radiographic Systems Other Than Fluoroscopic, Dental, or Computed Tomography X-Ray Systems
Universal Citation: LA Admin Code XV-606
Current through Register Vol. 50, No. 3, March 20, 2024
A. Beam Limitation. The useful beam shall be limited to the area of clinical interest. This requirement shall be deemed to have been met if a positive beam-limiting device has been properly used or if evidence of collimation is shown on at least three sides or three corners of the film (for example, projections from the shutters of the collimator, cone cutting at the corners, or borders at the film's edge).
1. General
Purpose Stationary and Mobile X-Ray Systems, Including Veterinary Systems
Installed after February 21, 1991. These systems shall meet the following
requirements:
a. there shall be provided a
means of stepless adjustment of the size of the X-ray field. The minimum field
size at an SID of 100 centimeters shall be equal to or less than 5 centimeters
by 5 centimeters;
b. a method shall
be provided for visually defining the perimeter of the X-ray field. The total
misalignment of the edges of the visually defined field with the respective
edges of the X-ray field along either the length or width of the visually
defined field shall not exceed 2 percent of the distance from the source to the
center of the visually defined field when the surface upon which it appears is
perpendicular to the axis of the X-ray beam;
c. when a light localizer is used to define
the X-ray field, it shall provide an average illumination of not less than 160
lux or 15 footcandles at 100 centimeters or at the maximum SID, whichever is
less. The average illumination shall be based upon measurements made in the
approximate center of each quadrant of the light field. Radiation therapy
simulation systems manufactured on and after May 27, 1980, are exempt from this
requirement;
d. the edge of the
light field at 100 cm or at the maximum SID, whichever is less, shall have a
contrast ratio, corrected for ambient lighting, of not less than 4 in the case
of beam-limiting devices designed for use on stationary equipment, and a
contrast ratio of not less than 3 in the case of beam-limiting devices designed
for use on mobile and portable equipment. The contrast ratio is defined as
I1/I2, where I1 is the illuminance 3 mm from the edge of the light field toward
the center of the field; and I2 is the illuminance 3 mm from the edge of the
light field away from the center of the field. Compliance shall be determined
with a measuring aperture of 1 mm; and
e. the department may grant an exemption on
X-ray systems to LAC 33:XV.606.A.1.a-d provided the registrant makes a written
application for such exemption and in that application:
i. demonstrates that it is impractical to
comply with LAC 33:XV.606.A.1.a-d; and
ii. the purposes of LAC 33:XV.606.A.1.a-d
will be met by other methods.
2. Additional Requirements for Stationary
General Purpose X-Ray Systems, Including Veterinary Systems Installed after
February 21, 1991. In addition to the requirements of LAC 33:XV.606.A.1,
stationary general purpose X-ray systems shall meet the following requirements:
a. a method shall be provided to indicate
when the axis of the X-ray beam is perpendicular to the plane of the image
receptor, to align the center of the X-ray field with respect to the center of
the image receptor to within 2 percent of the SID, and to indicate the SID to
within 2 percent;
b. the
beam-limiting device shall indicate numerically the field size in the plane of
the image receptor to which it is adjusted;
c. indication of the field size dimensions
and SID's shall be specified in inches and/or centimeters, and shall be such
that aperture adjustments result in X-ray field dimensions in the plane of the
image receptor that correspond to those indicated by the beam-limiting device
to within 2 percent of the SID when the beam axis is indicated to be
perpendicular to the plane of the image receptor; and
d. compliance measurements will be made at
discrete SIDs and image receptor dimensions in common clinical use or at any
other specific dimensions at which the beam-limiting device or its associated
diagnostic X-ray system is uniquely designed to operate.
3. X-Ray Systems Designed for One Image
Receptor Size. Radiographic equipment designed for only one image receptor size
at a fixed SID shall be provided with means to limit the field at the plane of
the image receptor to dimensions no greater than those of the image receptor,
and to align the center of the X-ray field with the center of the image
receptor to within 2 percent of the SID, or shall be provided with means to
both size and align the X-ray field such that the X-ray field at the plane of
the image receptor does not extend beyond any edge of the image
receptor.
4. Beam Limitation and
Alignment on Stationary General Purpose X-Ray Systems. For stationary, general
purpose X-ray systems that contain a tube housing assembly, an X-ray control,
and for those systems so equipped, with a table, all certified in accordance
with the USFDA regulations, the following requirements apply.
a. Positive beam limitation (PBL) shall be
provided whenever all the following conditions are met:
i. the image receptor is inserted into a
permanently mounted cassette holder;
ii. the image receptor length and width are
each less than 50 centimeters;
iii.
the X-ray beam axis is within +3 degrees of vertical, and the SID is 90
centimeters to 130 centimeters inclusive, or the X-ray beam axis is within +3
degrees of horizontal, and the SID is 90 centimeters to 205 centimeters
inclusive;
iv. the X-ray beam axis
is perpendicular to the plane of the image receptor to within +3
degrees;
v. neither tomographic nor
stereoscopic radiography is being performed; and
vi. the PBL system has not been intentionally
overridden. This override provision is subject to LAC
33:XV.606.A.4.c.
b.
Positive beam limitation (PBL) shall prevent the production of X-rays when:
i. either the length or width of the X-ray
field in the plane of the image receptor differs, except as permitted by LAC
33:XV.606.A.4.e., from the corresponding image receptor dimensions by more than
3 percent of the SID;
ii. the sum
of the length and width differences as stated in LAC 33:XV.606. A.4.b.i.
without regard to sign exceeds 4 percent of the SID; or
iii. the beam-limiting device is at an SID
for which PBL is not designed for sizing.
c. If a means of overriding the positive beam
limitation (PBL) system exists, that means shall meet the following criteria:
i. the means of overriding the PBL system
shall be designed for use only in the event of PBL system failure or if the
system is being serviced; and
ii.
if in a position that the operator would consider it part of the operational
controls or if it is referenced in the operator's manual or in other materials
intended for the operator, the means for overriding the PBL system shall
require that:
(a). a key be utilized to defeat
the PBL;
(b). the key remain in
place during the entire time the PBL system is overridden; and
(c). the key or key switch be clearly and
durably labeled as follows:
FOR X-RAY FIELD LIMITATION SYSTEM FAILURE
d. Compliance with LAC 33:XV.606. A.4.b.
shall be determined when the equipment indicates that the beam axis is
perpendicular to the plane of the image receptor and the provisions of LAC
33:XV.606. A.4.a. are met. Compliance shall be determined no sooner than five
seconds after insertion of the image receptor.
e. The positive beam limitation system shall
be capable of operation, at the discretion of the operator, such that the size
of the field may be made smaller than the size of the image receptor through
stepless adjustment of the field size. The minimum field size at a SID of 100
centimeters shall be equal to or less than 5 centimeters by 5
centimeters.
f. The positive beam
limitation system shall be designed such that if a change in image receptor
does not cause an automatic return to positive beam limitation function as
described in LAC 33:XV.606.A.5.b, then any change of image receptor size or SID
shall cause the automatic return.
5. X-Ray Systems Other Than Those Described
in LAC 33:XV.606.A.1, 2, 3, and 4, including Veterinary Systems Prior to
February 21, 1991. These systems shall meet the following requirements:
a. a means shall be provided to limit the
X-ray field in the plane of the image receptor so that such field does not
exceed each dimension of the image receptor by more than 2 percent of the SID
when the axis of the X-ray beam is perpendicular to the plane of the image
receptor;
b. a means shall be
provided to align the center of the X-ray field with the center of the image
receptor to within 2 percent of the SID, or means shall be provided to both
size and align the X-ray field such that the X-ray field at the plane of the
image receptor does not extend beyond any edge of the image receptor.
Compliance shall be determined with the axis of the X-ray beam perpendicular to
the plane of the image receptor; and
c. LAC 33:XV.606.A.5.a and b may be met with
a system that meets the requirements for a general purpose X-ray system as
specified in LAC 33:XV.606.A.1 or, when alignment means are also provided, may
be met with either:
i. an assortment of
removable, fixed-aperture, beam-limiting devices sufficient to meet the
requirement for each combination of image receptor size and SID for which the
unit is designed with each such device having clear and permanent markings to
indicate the image receptor size and SID for which it is designed; or
ii. a beam-limiting device having multiple
fixed apertures sufficient to meet the requirement for each combination of
image receptor size and SID for which the unit is designed. Permanent, clearly
legible markings shall indicate the image receptor size and SID for which each
aperture is designed and shall indicate which aperture is in position for
use.
B. Radiation Exposure Control Devices
1. Exposure Initiation. A means shall be
provided to initiate the radiation exposure by a positive action on the part of
the operator, such as the depression of a switch. Radiation exposure shall not
be initiated without such a positive action. In addition, it shall not be
possible to initiate an exposure when the timer is set to a "zero" or "off"
position if either position is provided.
2. Exposure Termination
a. Manual Exposure Control. An X-ray exposure
control shall be incorporated into each X-ray system such that an exposure can
be terminated by the operator at any time ("deadman" switch) except for:
i. exposures of 1/2 second or less;
or
ii. during serial radiography
when means shall be provided to permit completion of any single exposure of the
series in process.
b.
Automatic Exposure Control. When an automatic exposure control is provided:
i. indication shall be made on the control
panel when this mode of operation is selected;
ii. if the X-ray tube potential is equal to
or greater than 50 kVp, the minimum exposure time for field emission equipment
rated for pulsed operation shall be equal to or less than a time interval
equivalent to two pulses;
iii. the
minimum exposure time for all equipment other than that specified in LAC
33:XV.606.B.2.b.ii shall be equal to or less than 1/60 second or a time
interval required to deliver 5 mAs, whichever is greater;
iv. either the product of peak X-ray tube
potential, current, and exposure time shall be limited to not more than 60 kWs
per exposure, or the product of X-ray tube current and exposure time shall be
limited to not more than 600 mAs per exposure, except that when the X-ray tube
potential is less than 50 kVp, the product of X-ray tube current and exposure
time shall be limited to not more than 2,000 mAs per exposure; and
v. a visible signal shall indicate when an
exposure has been terminated at the limits specified in LAC 33:XV.606.B.2.b.iv,
and manual resetting shall be required before further automatically timed
exposures can be made.
3. Exposure Indication. The X-ray exposure
control shall provide visual or audible indication of X-ray production
observable at or from the operator's protected position whenever X-rays are
produced.
4. Exposure Duration
(Timer) Reproducibility. With a timer setting of 0.5 seconds or less, the
difference between the maximum exposure time (Tmax) and
the minimum exposure time (Tmin) shall be less than or
equal to 10 percent of the average exposure time (T), when four timer tests are
performed:
5. Exposure
Control Location. The X-ray exposure control shall be so placed that the
operator can view the patient while making any exposure.
6. Operator Protection Except for Veterinary
Systems and Panoramic Dental Systems. The following requirements shall be met:
a. stationary X-ray systems shall be required
to have the X-ray control, including the exposure switch, permanently mounted
in a protected area so that the operator is required to remain in that
protected area during the entire exposure; and
b. mobile and portable X-ray systems that
are:
i. used continuously for more than one
week in the same location, e.g., a room or suite, shall meet the requirements
of Subparagraph B.6.a of this Section; and
ii. used for less than one week in the same
location shall be provided with either a protective barrier at least 6.5 feet
(2 meters) high for operator protection during exposures, or means shall be
provided to allow the operator to be at least 12 feet (3.7 meters) from the
tube housing assembly during the exposure.
7. Operator Protection for Veterinary Systems
and Panoramic Dental Systems. All stationary, mobile, or portable X-ray systems
used for veterinary work or panoramic dental systems shall be provided with
either a 6.5 feet (2 meters) high protective barrier for operator protection
during exposures, or shall be provided with means to allow the operator to be
at least 12 feet (3.7 meters) from the tube housing assembly during exposures.
Otherwise, in cases where animals are held, the operator and ancillary
personnel shall be protected by a minimum of 0.25 mm lead equivalent from
scatter radiation and 0.5 mm from the useful beam.
8. Multiple Tubes. Where two or more
radiographic tubes are controlled by one exposure switch, the tube or tubes
which have been selected shall be clearly indicated before initiation of the
exposure. This indication shall be both on the X-ray control and at or near the
tube housing assembly which has been selected.
C. Source-to-Skin Distance. All mobile or portable radiographic systems shall be provided with means to limit the source-to-skin distance to be equal to or greater than 30 centimeters, except veterinary equipment.
D. Exposure Reproducibility. When all technique factors are held constant, including control panel selections associated with automatic exposure control (phototiming) systems, the coefficient of variation of exposure for both manual and phototimed systems shall not exceed 0.05. This requirement shall be deemed to have been met if, when 10 exposures are made at identical technique factors, the difference between the maximum exposure (Emax) and the minimum exposure (Emin) shall be less than or equal to 10 percent of the average exposure (E):
E. Radiation from Capacitor Energy Storage Equipment in Standby Status. Radiation emitted from the X-ray tube when the exposure switch or timer is not activated shall not exceed a rate of 2 milliroentgens (0.516 [MICRO]C/kg) per hour at 5 centimeters from any accessible surface of the diagnostic source assembly, with the beam-limiting device fully open, the system fully charged, and the exposure switch, timer, or any discharge mechanism not activated. Compliance shall be determined by measurements averaged over an area of 100 square cm, with no linear dimensions greater than 20 cm.
F. Accuracy. Deviation of technique factors from indicated values shall not exceed the limits specified for that system by its manufacturer. In the absence of manufacturer's specifications, the deviation shall not exceed 10 percent of the indicated value.
G. Linearity. The following requirements apply when the equipment is operated on a power supply as specified by the manufacturer for any fixed X-ray tube potential within the range of 40 percent to 100 percent of the maximum rated.
1. Equipment Having Independent Selection of
X-Ray Tube Current (mA). The average ratios of exposure to the indicated
milliampere-seconds product (C/kg/mAs or mR/mAs) obtained at any two
consecutive tube current settings shall not differ by more than 0.10 times
their sum. This is:
where:
X1 and X2 are the average C/kg/mAs (or mR/mAs) values obtained at any two consecutive mAs selector settings.
2.
Equipment Having a Combined X-Ray Tube Current Exposure Time Product (mAs)
Selector. The average ratios of exposure to the indicated milliampere-seconds
product (C/kg/mAs or mR/mAs) obtained at any two consecutive mAs selector
settings shall not differ by more than 0.10 times their sum. This is:
where:
X1 and X2 are the average C/kg/mAs (or mR/mAs) values obtained at any two consecutive mAs selector settings.
3.
Measuring Compliance. Determination of compliance shall be based on 10
exposures, of no less than 0.05 seconds each, taken within a time period of one
hour, at each of the two settings. These two settings may include any two focal
spot sizes provided that neither focal spot size is equal to or less than 0.45
millimeter, in which case the two settings shall be restricted to the same
focal spot size. For purposes of this requirement, focal spot size is the
nominal focal spot size specified by the X-ray tube manufacturer.
H. Portable Radiographic X-Ray Systems. A tube stand or other mechanical support shall be used for portable X-ray systems except during veterinary field operations where it is impractical to do so.
I. Systems Designed for Mammography. Systems designed for mammography use shall meet all applicable sections of the most current Mammography Quality Standards Act.
AUTHORITY NOTE: Promulgated in accordance with R.S. 30:2001 et seq. and 2104.B.
Disclaimer: These regulations may not be the most recent version. Louisiana may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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