Current through Register Vol. 42, No. 11, August 30, 2024
(1)
Scope. Rule
420-3-26-.03 establishes
standards for use of x-rays in the healing arts including but not limited to
medicine, dentistry, osteopathy, chiropractic, podiatry, and veterinary
medicine or servicers of x-ray equipment. The provisions of this Rule are
written in addition to, and not in substitution for, other applicable
provisions of these regulations. Periodic inspections will be performed of all
registrants. The inspection frequency will depend upon available personnel and
work load, but every x-ray unit ideally should be inspected not less than once
every two years.
(2) Definitions.
(a) "Agency" means the State Board of
Health.
(b) "ARCR" means the
Alabama Regulations for Control of Radiation.
(c) "Aluminum Equivalent" means the thickness
of aluminum affording the same attenuation, under specified conditions, as the
material in question.
(d) "Dead Man
Switch" means a switch so constructed that a circuit closing contact can only
be maintained by continuous pressure by the operator.
(e) "Diagnostic Tube Housing" means an x-ray
tube housing so constructed that the leakage radiation with the port closed at
a distance of one (1) meter in any direction from the target cannot exceed one
hundred (100) milliroentgens in one (1) hour when the tube is operated at any
of its specified ratings.
(f)
"Filter" means material placed in the useful beam to absorb preferentially the
less penetrating radiations.
(g)
"Half-Value Layer (hvl)" means the thickness of absorber required to reduce a
beam of radiation to one-half (1/2) its incident exposure rate.
(h) "High Radiation Area" means any area in
which there exists radiation or such levels that a major portion of the body
could receive in any one (1) hour a dose in excess of 100 millirems.
(i) "Inherent Filtration" means the
filtration in the useful beam due to the window of the x-ray tube and any
permanent tube enclosure.
(j)
"Interlock" means a device for precluding access to an area of radiation hazard
either by preventing entry or by automatically removing the hazard.
(k) "Kilovolts Peak (kVp)" means the crest
value in kilovolts of the potential of a pulsating potential generator.
(l) "Lead Equivalent" means the
thickness of lead affording the same attenuation under specified conditions as
the material in question.
(m)
"Leakage Radiation" means all radiation coming from within the tube housing
except the useful beam.
(n) "Mobile
X-Ray Unit" means a unit that is not permanently fixed to a definite location
in a building or vehicle.
(o)
"Personnel Monitoring Equipment" means devices designed to be worn or carried
by an individual for the purpose of measuring the dose received (film badges,
pocket dosimeters).
(p) "Primary
Protective Barrier" means a barrier sufficient to attenuate the useful beam to
the required degree.
(q)
"Protective Apron" means a barrier of attenuating materials, used to reduce
radiation exposure.
(r) "Protective
Barrier" means a barrier of attenuating materials, used to reduce radiation
exposure.
(s) "Protective Glove"
means a glove made of attenuating materials used to reduce radiation
exposure.
(t) "Radiation." The word
radiation shall mean ionizing radiation, that is any electromagnetic or
particulate radiation capable of producing ions directly or indirectly in its
passage through matter.
(u)
"Radiation Area" means any area in which there exists radiation at such levels
that a major portion of the body could receive in any one (1) hour a dose in
excess of 5 millirems, or in any five (5) consecutive days a dose in excess of
100 millirems.
(v) "Restricted
Area" means any area to which access is controlled by the registrant for
purposes of protection of individuals from exposure to radiation. "Restricted
area" shall not include any areas used for residential quarters, although upon
authorization by the Agency a separate room or rooms in a residential building
may be set apart as a restricted area.
(w) "Scatter Radiation" means secondary
radiation or radiation that, during passage through matter has been deviated in
direction.
(x) "Secondary
Protective Barrier" means a barrier sufficient to attenuate stray radiation to
the required degree.
(y) "Shutter"
means a device, generally of lead, fixed to an x-ray housing to intercept the
useful beam.
(z) "Stray Radiation"
means radiation not serving any useful purpose. It includes leakage and
scattered radiation.
(aa)
"Therapeutic Type Tube Housing" means an x-ray tube housing so constructed that
the leakage radiation with the port closed at a distance of one (1) meter in
any direction from the target cannot exceed one (1) roentgen in one (1) hour
and at a distance of five (5) centimeters from any point of the surface of the
housing accessible to the patient, cannot exceed thirty (30) roentgens in one
(1) hour when the tube is operated at any of its specified ratings.
(bb) "Useful Beam" means that part of the
radiation which passes through the window, aperture, cone, or other collimating
device of the tube housing.
(cc)
"Services" means the installation, calibrating, repairing, maintaining or
performing a radiation protection survey of an x-ray producing machine or
associated x-ray component.
(dd)
"Healing Arts" means the practice of medicine, dentistry, osteopathy,
chiropractic, podiatry, and for nonhumans, veterinary medicine.
(ee) "Portable" means x-ray equipment
designed to be hand-carried.
(ff)
"Stationary" means x-ray equipment which is installed in a fixed
location.
(gg) "Gonad Shield" means
a primary protective barrier for the testes or ovaries.
(hh) "Image Receptor" means any device, such
as a fluorescent screen or radiographic film, which transforms incident x-ray
photons either into a visible image or into another form which can be made into
a visible image by further electronic or chemical transformations.
(3) General Safety Provisions.
(a) The Agency may waiver compliance with the
specific requirements of this Rule by an existing machine or installation if
(1) such compliance would require replacement or substantial modification of
the machine or installation and (2) the registrant demonstrates, to the
Agency's satisfaction, achievement through other means of radiation protection
equivalent to that required by these rules.
(b) Persons shall not be exposed to the
useful beam except for healing arts purposes, each exposure of which shall be
authorized by:
1. A licensed practitioner of
the healing arts; or
2. A licensed
physician's assistant, a certified registered nurse practitioner, or a
certified nurse midwife subject to the rules of his/her licensure
board.
(c) A written
order for each exposure shall be prepared by the licensed practitioner of the
healing arts, certified registered nurse practitioner or certified nurse
midwife and provided to the individual administering the radiation. This order
shall, at a minimum, include the following information:
1. Patient's name;
2. Date of birth;
3. Examination(s) requested;
4. Related diagnosis;
5. Name of the individual ordering the
exposure; and
6. Date of the
order.
(d) These rules
specifically prohibit deliberate exposure for the following purposes:
1. Exposure of an individual for training,
demonstration, or other purposes unless (a) there are also healing arts
requirements and proper prescription has been provided, (b) the radiographs are
made for the student's own training, (c) the radiographs are made only once
with no more than two retakes and if only a small tissue volume (e.g. less than
a skull) is exposed per radiograph, and (d) the images are properly interpreted
and are made a part of the dental or medical record.
2. Exposure of an individual for the purpose
of healing arts screening without prior written approval of the Agency.
(Screening means an exposure of a person without prior examination or a
determination of a specific individual need by a licensed
practitioner).
(e)
Personnel Monitoring. Each registrant shall provide personnel monitoring
devices which shall be used by:
1. Each
individual who receives, or is likely to receive, whole body dose in excess of
25 milliroentgens per week;
2. Each
individual who enters a high radiation area;
3. Each individual who operates mobile x-ray
equipment;
4. Each individual who
operates fluoroscopic equipment;
5.
Each individual while he services an operable x-ray producing
machine.
(f) Use.
1. The registrant shall be responsible for
assuring that all requirements of Rule
420-3-26-.03 are met.
2. The registrant shall assure that all x-ray
equipment under his control is operated only by individuals adequately
instructed in safe operating procedures and competent in safe use of the
equipment.
3. After October 1,
1974, no registrant who services x-ray producing equipment shall permit any
person to service such equipment, when operable, until such person has been
appropriately instructed in the subjects outlined in Appendix A of Rule
420-3-26-.05 of these rules and
shall have demonstrated an understanding thereof.
4. The speed of film or screen and film
combinations shall be the fastest speed consistent with the diagnostic
objectives of the examination.
5.
Portable or mobile x-ray equipment shall be used only for examinations where it
is impractical to transfer the patient to a stationary radiographic
installation.
(g)
Shielding.
1. Each installation shall be
provided with such primary barriers and/or secondary barriers as are necessary
to assure compliance with
420-3-26-.03(2),
420-3-26-.03(5),
and 420-3-26-.03(6).
This requirement shall be deemed to be met if the thickness of such barriers is
equivalent to those as computed in accordance with National Council on
Radiation Protection and Measurements Report No.
49.2
(h) Darkroom Requirements. To reduce
unnecessary re-exposures of patients resulting from film processing problems:
1. The darkroom shall be
light-proof.
2. The area in which
undeveloped films are handled for processing shall be devoid of light, during
handling and processing, with the exception of light in the wave lengths having
no specific effects on the radiographic film.
3. A thermometer and timer operable and
appropriate to the type of film processing shall be in use in the darkroom. The
use of properly maintained automatic film processing equipment shall meet this
requirement for all film so processed.
(4) Fluoroscopic Installations.
(a) Equipment.
1. The tube housing shall be of diagnostic
type.
2. The target-to-panel or
target-to-table top distance of equipment installed before the effective date
of these rules
52 shall not be less than twelve (12)
inches, and shall not be less than fifteen (15) inches in equipment installed
thereafter.
3. The total filtration
permanently in the useful beam shall not be less than 2.5 millimeters aluminum
equivalent. This requirement may be assumed to have been met if the half-value
layer is not less than 2.5 millimeters aluminum at normal operating voltages.
2Available from NCRP Publications,
7910 Woodmont Avenue, Suite 1016 Bethesda, Md. 20814
52 June 15, 1966.
4. The equipment shall be so constructed that
the entire cross section of the useful beam is attenuated by a primary barrier.
This barrier is usually the viewing device, either a conventional fluoroscopic
screen or an image intensification mechanism.
(i) For equipment installed before the
effective date of the rules
52, the required lead equivalent of the
barrier shall not be less than 1.5 millimeters for 100 kVp, shall not be less
than 1.8 millimeters for 125 kVp or shall not be less than 2.0 millimeters for
150 kVp.
For equipment installed or re-installed after the effective
date of these rules
52 the required lead equivalent of the
barrier shall not be less than 2.0 millimeters for 125 kVp, or shall not be
less than 2.7 millimeters for 150 kVp.
For conventional fluoroscopes the requirements of paragraph (i)
may be assumed to have been met if the exposure rate measured at the viewing
surface of the fluorescent screen does not exceed fifty (50) milliroentgens per
hour with the screen in the primary beam of the fluoroscope without a patient,
under normal operating conditions.
(ii) Collimators shall be provided to
restrict the size of the useful beam to less than the area of the barrier. For
conventional fluoroscopes this requirement is met if, when the adjustable
diaphragm is opened to its fullest extent, an unilluminated margin is left on
the fluorescent screen with the screen centered in the beam at a distance of
fourteen (14) inches from the panel or table top. The margin requirement does
not apply to installations where image intensifiers are used, but a protective
shield shall be provided in these installations so that the useful beam does
not produce a radiation hazard; however, the useful beam may not exceed the
viewing area by more than 2% of the source to image receptor distance for any
dimension.
(iii) The tube mounting
and the barrier shall be so linked together that under conditions of
fluoroscopic use, the barrier always intercepts the useful beam.
(iv) Collimators and adjustable diaphragms or
shutters to restrict the size of the useful beam to the area of clinical
interest and shall provide a minimum of 2.0 millimeters lead-equivalent
protection for 100 kVp, 2.4 millimeters for 125 kVp, or 2.7 millimeters for 150
kVp.
5. The exposure
switch shall be of the dead-man type.
6. A manual-reset, cumulative timing device
shall be used which will either indicate elapsed time by an audible signal or
turn off the apparatus when the total exposure exceeds a predetermined limit in
one or a series of exposures. The device shall have a maximum time range of
five minutes.
7. For fluoroscopy,
the exposure rate measured at the panel or table top shall not exceed ten (10)
roentgens per minute. This does not apply during cinegraphic
procedures.
8. Unless measurements
indicate otherwise, protective aprons of at least a quarter millimeter lead
equivalent shall be worn by all persons in the fluoroscopic room except the
patient.
9. Protective gloves of a
least a quarter millimeter lead equivalent shall be worn by the fluoroscopist
during every examination.
10.
Mobile fluoroscopic equipment shall meet the requirements of this Rule where
applicable, except that:
(i) In the absence
of a table top, a cone or spacer frame shall limit the target-to-skin distance
to not less than 20 centimeters.
(ii) Image intensification shall always be
provided. Conventional fluoroscopic screens shall not be used.
(iii) It shall be impossible to operate a
machine when the collimating cone or diaphragm is not in place.
(iv) The exposure rate measured at the 30 cm
from image receptor shall not exceed ten (10) roentgens per minute.
(b) Structural
Shielding. Ordinarily, only secondary barriers are necessary except for
combined fluoroscopic-radiographic installations.
(5) Radiographic Installations Other than
Dental and Veterinary Medicine.
(a)
Equipment.
1. The tube housing shall be of a
diagnostic type.
2.
(i) Diaphragms or cones shall be provided for
collimating the useful beam. When round collimators are used, the diameter of
the beam at the film location shall be no greater than the diagonal dimension
of the film plus three percent of the source to image receptor distance. For
rectangular collimators, the beam size shall be no greater than the film
dimension plus three percent of the source to image receptor distance. The
diaphragms or cones shall provide the same degree of protection as the tube
housing.
(ii) Adjustable
collimators installed after the effective date of these rules
53 shall incorporate light beams to define
the projected dimensions of the useful beam.
3.
(i)
Except when contraindicated for a particular medical purpose, for equipment
operation at seventy (70) kVp, and below, the total filtration permanently in
the useful beam shall be equivalent to at least 1.5 mm of aluminum. This
requirement may be assumed to have been met if the half-value layer is not less
than 1.5 mm aluminum at normal operating voltages.
(ii) Except when contraindicated for a
particular medical purpose, for equipment capable of operating above seventy
(70) kVp the total filtration permanently in the useful beam shall be
equivalent to at least 2.5 mm of aluminum. This requirement may be assumed to
have been met if the half-value layer is not less than 2.5 mm aluminum at
normal operating voltages.
4. A device shall be provided to terminate
the exposure after a preset time interval, preset product of current and time
(mAs), a preset number of pulses, or a preset radiation exposure to the image
receptor. It shall not be possible to make an exposure when the timer is set to
a zero or off position, if either position is provided.
5. A dead-man type of exposure switch shall
be so arranged that it cannot be conveniently operated out of a shielded area.
Exposure switches for "spot-film" devices used in conjunction with fluoroscopic
tables are exempted from this shielding requirement.
(b) Structural Shielding.
1. All wall, floor and ceiling areas exposed
to the useful beam shall have primary barriers. Primary barriers in walls shall
extend to a minimum height of eighty-four (84) inches above the floor of the
area being shielded.
53 March 18, 1970.
2. Secondary barriers shall be provided in
all wall, floor, and ceiling areas not having primary barriers or where the
primary barrier's requirements are lower than the secondary barrier's
requirements.
3. The operator's
station at the control shall be behind a protective barrier, either in a
separate room, in a protected booth, or behind a shield which will intercept
the useful beam and any radiation which has been scattered only once.
4. A window of lead-equivalent glass equal to
that required by the adjacent barrier or a mirror system shall be provided
large enough and so placed that the operator can see the patient without having
to leave the protected area during exposure, and shall meet the requirements of
420-3-26-.05, Appendix C
3.
(c) Operating
Procedures.
1. No individual exposed to
occupational radiation shall hold patients during exposures except during
emergencies, nor shall any individual be regularly used for this service. If
the patient must be held by an individual, that individual shall be protected
with appropriate shielding devices such as protective gloves and apron and he
shall be so positioned that no part of his body will be struck by the useful
beam.
2. Only the operators of
radiographic equipment, other required individuals, and the patient shall be
present during exposures. No unprotected parts of the operator's body shall be
in the useful beam.
3. The useful
beam shall be restricted to the area of clinical interest.
(6) Mobile Diagnostic Radiographic
Equipment.
(a) Equipment.
1. All requirements of
420-3-26-.06(5)(a)
apply except
420-3-26-.06(5)(a)5.
2. The exposure control switch
shall be of the dead-man type and shall be so arranged that the operator can
stand at least six (6) feet from the patient and well away from the useful
beam.
(b) Structural
Shielding.
1. When a mobile unit is used
routinely in one location, it shall be considered a fixed installation subject
to shielding requirements specified in
420-3-26-.06(3)(d) and (5)
(b).
(c) Operating Procedures.
1. All provisions of
420-3-26-.06(5)(c)
apply except (5) (c)2.
2. The target-to-skin distance shall not be
less than twelve (12) inches.
(7) Chest Photofluorographic Installations.
(a) Equipment.
1. All provisions of 420-3-26 -.06(5)(a)
apply.
2. A collimator shall
restrict the useful beam to the area of the photofluorographic
screen.
(b) Structural
Shielding.
1. All provisions of 420-3-26
-.06(3)(d) and
420-3-26-.05(5)(b)
apply.
(c) Operating Procedures.
1. All provisions of
420-3-26-.06(5)(c)
apply.
2. All individuals except
the patient being examined shall be in shielded positions during
exposures.
(8) Dental Radiographic Installations.
(a) Equipment.
1. The tube housing shall be of diagnostic
type.
2. Diaphragms or cones shall
be used for collimating the useful beam and shall provide the same degree of
protection as the housing. The diameter of the useful beam at the cone tip
shall not be more than three (3) inches.
3. A cone or spacer frame shall provide a
target-to-skin distance of not less than seven (7) inches with apparatus
operating above fifty (50) kVp or four (4) inches with apparatus operating at
fifty (50) kVp or below.
4.
(i) For equipment operating up to seventy
(70) kVp, the total filtration permanently in the useful beam shall be
equivalent to at least 1.5 mm of aluminum. This requirement may be assumed to
have been met if the half-value layer is not less than 1.5 mm aluminum at
normal operating voltages.
(ii) For
equipment operating above seventy (70) kVp, the total filtration permanently in
the useful beam shall be equivalent to at least 2.5 mm of aluminum. This
requirement may be assumed to have been met if the half-value layer is not less
than 2.5 mm of aluminum at the normal operating voltages.
5. A device shall be provided to terminate
the exposure after a preset time interval, preset product of current and time
(mAs), a preset number of pulses, or a preset radiation exposure to the image
receptor. It shall not be possible to make an exposure when the timer is set at
a zero or off position, if either position is provided. Except for dental
panoramic systems, termination of exposure shall cause automatic resetting of
the time to its initial setting or to zero.
6. The exposure control switch shall be of
the dead-man type.
7. Each
installation shall be provided with a protective barrier for the operator or
shall be so arranged that the operator can stand at least six (6) feet from the
patient and well away from the useful beam.
(b) Structural Shielding.
1. Dental rooms containing x-ray machines
shall be provided with primary barriers for all areas struck by the useful
beam.
2. When dental x-ray units
are installed, the rooms adjacent will be adequately protected.
NOTE: In most cases structural materials or
ordinary walls suffice as a protective barrier without addition of special
shielding material.
(c) Operating Procedures.
1. Neither the dentist nor his assistant
shall be permitted to hold patients or films during exposure, nor shall any
individual be regularly used for this service.
2. During each exposure, the operator shall
stand at least six (6) feet from the patient or behind a protective
barrier.
3. Only the patient shall
be in the useful beam.
4. Neither
the tube housing nor the pointer cone shall be hand-held during
exposure.
5. Fluoroscopy shall not
be used in dental examinations.
(9) Therapeutic X-ray Installations.
(a) Equipment.
1. The tube housing shall be of therapeutic
type.
2. Permanent diaphragms or
cones used for collimating the useful beam shall afford the same degree of
protection as the tube housing. Adjustable or removable beam-defining
diaphragms or cones shall transmit not more than five (5) percent of the useful
beam obtained at the maximum kilovoltage and with maximum treatment
filter.
3. Filters shall be secured
in place to prevent them from dropping out during treatment. The filter slot
shall be so constructed that the radiation escaping through it does not exceed
one (1) roentgen per hour at one (1) meter, or if the radiation from the slot
is accessible to the patient, thirty (30) roentgens per hour at five (5)
centimeters from the external opening.
4. The x-ray tube shall be so mounted that it
cannot turn or slide with respect to the aperture.
5. Means shall be provided to immobilize the
tube housing during stationary portal treatment.
6. A timer shall be provided to terminate the
exposure after a preset time regardless of what other exposure limiting devices
are present.
7. Equipment utilizing
shutters to control the useful beam shall have a shutter position indicator on
the control.
8. There shall be on
the control panel an easily discernible indicator which will give positive
information as to whether or not the x-ray tube is energized.
(b) Structural Shielding.
1. All wall, floor, and ceiling areas that
can be struck by the useful beam, plus a border of one foot, shall be provided
with primary protective barriers.
2. All wall, floor, and ceiling areas that
cannot be struck by the useful beam shall be provided with secondary
barriers.
3. With equipment
operating above one hundred and twenty-five (125) kVp, the required barriers
shall be an integral part of the building.
4. With equipment operating above one hundred
and fifty (150) kVp, the control panel shall be within a protective booth
equipped with an interlocked door, or outside the treatment room.
5. Interlocks shall be provided for x-ray
therapy equipment capable of operating above 150 kVp so that, when any door of
the treatment room is opened, either the machine will shut off automatically or
the radiation level within the room will be reduced to an average of not more
than two milliroentgens per hour and a maximum of ten milliroentgens per hour
at a distance of one (1) meter in any direction from the target. After such
shut off or reduction in output, it shall be possible to restore the machine to
full operation only from the control panel.
6. Provisions shall be made to permit
continuous observation of patients during irradiation.
7. Windows, mirror systems, or closed-circuit
television viewing screens used for observing the patient shall be so located
that the operator may see the patient and the control panel from the same
position.
(c) Operating
Procedures.
1. All new installations shall
have a protection survey made by, or under the direction of, a qualified
expert. This shall also be done after any change in the installation which
might produce a radiation hazard. The expert shall report his findings in
writing to the person in charge of the installation and to the Agency (State
Board of Health).
NOTE: Paragraph (c)1. of
420-3-26-.06(9),
Rule was revised by the State Board of Health on March 19, 1979.
2. The installation shall be
operated in compliance with any limitations indicated by the protection
survey.
3. No individual who works
with radiation, unless he is the patient, shall be in the treatment room during
exposure. No other individual shall be there except when it is clinically
necessary. If any individual is required to be in the treatment room with the
patient during exposure, he shall be protected as much as possible from
scattered radiation, and shall not be in the useful beam.
4. Records of surveys required by
subparagraph (4) of this paragraph shall be maintained for two years after the
facility has ceased to be used as described in the survey. If the survey was
used to determine an individual's exposure, the record must be maintained until
disposal is authorized by the Agency.
(d) All provisions of this Section apply to
therapeutic veterinary installations.
(e) The output of each therapeutic x-ray
machine shall be calibrated by, or under the direction of, a qualified expert.
The calibration shall be repeated after any change in or replacement of
components of the x-ray generating equipment which could cause a change in
x-ray output. Check calibrations shall be made at least one a year thereafter.
Records of calibration shall be maintained by the registrant.
(10) X-ray Therapy Equipment
Operated at Potentials of Sixty (60) KV and Below.
(a) Equipment.
1. All provisions of 420-1-26-.06(9)(a)
apply, except for equipment used for "contact therapy",
420-3-26-.06(9)(a)
in which instance the leakage radiation at
the surface of the tube housing shall not exceed 0.1 roentgen per
hour.
2. There shall be on the
control panel some easily discernible device which will give positive
indication as to whether or not the tube is energized.
(b) Operating Procedures.
1. Automatic timers shall be provided which
will permit accurate presetting and determination of exposures as short as one
second.
2. In the therapeutic
application of apparatus constructed with beryllium or other low-filtration
windows, the registrant shall insure that the unfiltered radiation reaches only
the part intended and that the useful beam is blocked at all times except when
actually being used.
3. Machines
having an output of more than 1,000 roentgens per minute at any accessible
place shall not be left unattended without the power being shut off at the
primary disconnecting means.
4. If
the tube is hand-held during irradiation, the operator shall wear protective
gloves and apron.
(11) Veterinary Medicine Radiographic
Installations.
(a) Equipment.
1. The tube housing shall be of diagnostic
type.
2. Diaphragms or cones shall
be provided for collimating the useful beam to the area of clinical interest
and shall provide the same degree of protection as required of the housing, as
indicated in
420-3-26-.06(5)(a)2.(i) and
(ii).
3. Except when contraindicated for a
particular radiographic purpose, the total filtration permanently in the useful
beam shall not be less than 1.5 millimeters aluminum-equivalent for equipment
operating up to seventy (70) kVp and 2.0 millimeters aluminum-equivalent for
machines operated in excess of seventy (70) kVp.
4. A device shall be provided to terminate
the exposure after a preset time interval, preset product of current and time
(mAs), a preset number of pulses, or a preset radiation exposure to the image
receptor. It shall not be possible to make an exposure when the timer is set at
a zero or off position, if either position is provided.
5. A dead-man type of exposure switch shall
be provided, together with an electrical cord of sufficient length so that the
operator can stand out of the useful beam at least six (6) feet from the animal
during all x-ray exposures.
(b) Structural Shielding.
1. All wall, floor, and ceiling areas shall
be provided with applicable protective barriers as required in
420-3-26-.06(5)
(b).
(c) Operating Procedures.
1. The operator shall stand well away from
the tube housing and the animal during radiographic exposures. Provisions shall
be made so that it will not be necessary for the operator to stand in the
useful beam. Hand-held fluoroscopic screens shall not be used. The tube housing
shall not be held by the operator. No individual other than the persons
involved in the operation shall be in the x-ray room while exposures are being
made.
2. In any application in
which the operator or an assistant is not located behind a protective barrier,
a protective apron having a lead-equivalent of not less than 0.5 millimeter
shall be worn.
3. No individual
shall be regularly employed to hold or support animals or hold film during
radiation exposures. Occupationally exposed individuals shall not perform this
service except in cases in which no other method is available. Any individual
holding or supporting an animal during radiation exposure shall wear protective
gloves and apron having a lead-equivalent of not less than 0.5
millimeter.