Mississippi Administrative Code › Title 15 - Mississippi Department of Health › Part 21 - Division of Radiological Health › Subpart 78 - Radiological Health › Chapter 1 - REGULATIONS FOR CONTROL OF RADIATION IN MISSISSIPPI › Subchapter 6 - X-Rays In The Healing Arts › Rule 15-21-78-1.6.7 - Intraoral Dental Radiographic Systems

Current through June 25, 2024
In addition to the provisions of 1.6.3 and 1.6.4, the
						requirements of 1.6.7 apply to x-ray equipment and associated facilities used
						for dental radiography. Requirements for extraoral dental radiographic systems
						are covered in 1.6.6.
1.
					 Source-to-Skin Distance (SSD). X-ray systems designed for use with an intraoral
					 image receptor shall be provided with means to limit SSD, to not less than:
a. 18 centimeters if operable above 50 kVp;
					 or
b. 10 centimeters if not
					 operable above 50 kVp.
2
Field Limitation.
a. Radiographic systems designed for use with
					 an intraoral image receptor shall be provided with means to limit the x-ray
					 field such that the x-ray field at the minimum SSD shall be containable in a
					 circle having a diameter of no more than 7 centimeters; and
b. An open ended PID (position indicating
					 device) shall be used on new dental x-ray equipment purchased after the
					 effective date of these regulations.
3
Radiation Exposure Control for Certified and
						Noncertified Systems.
a
Exposure Initiation.
i. Means shall be provided to initiate the
					 radiation exposure by a deliberate action on the part of the operator, such as
					 the depression of a switch. Radiation exposure shall not be initiated without
					 such an action; and
ii. 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.
b
Exposure Termination.
i. Means shall be provided to terminate the
					 exposure at a preset time interval, preset product of current and time, a
					 preset number of pulses, or a preset radiation exposure to the image
					 receptor.
ii. 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, except for exposures of 1/2 second
					 or less.
iii. Termination of an
					 exposure shall cause automatic resetting of the timer to its initial setting or
					 to "zero".
c.
					 Exposure Indication. Means shall be provided for visual indication observable
					 at or from the operator's protected position whenever x-rays are produced. In
					 addition, a signal audible to the operator shall indicate that the exposure has
					 terminated.
d. Exposure Duration
					 (Timer) Reproducibility. With a timer setting of 0.5 seconds or less, the
					 difference between the maximum exposure time
					 (
T
max) and the minimum exposure time
					 (
T
min) shall be less than or equal to
					 10% of the average exposure time (
T
), when four timer test
					 are performed:
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e
Exposure Control Location and Operation
						Protection.
i. Stationary x-ray
					 systems shall be required to have the x-ray exposure control permanently
					 mounted in a protected area, so that the operator is required to remain in that
					 protected area during the entire exposure; and
ii. Mobile and portable x-ray systems which
					 are:
i. used for greater than one week in the
					 same location, i.e., a room or suite, shall meet the requirements of
					 1.6.7(3)(e)(i); 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 (2m) high for operator protection, or
					 means to allow the operator to be at least 12 feet (3.7 m) from the tube
					 housing assembly while making exposures.
4. Exposure Reproducibility. The coefficient
					 of variation shall not exceed 0.05 when all technique factors are held
					 constant. This requirement shall be deemed to have been met if, when 4
					 exposures are made within a period of one hour at identical technique factors,
					 the difference between the maximum exposure value
					 (
E
max) and the minimum exposure value
					 (
E
min) shall be less than or equal to
					 10% of the average exposure (
E
):
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5.
					 Linearity. When the equipment allows a choice of x-ray tube current settings
					 and is operated on a power supply as specified by the manufacturer in
					 accordance with any fixed x-ray tube potential within the range of 40 to 100
					 percent of the maximum rating, the average ratios of exposure to the indicated
					 millampere-seconds product obtained at any 2 consecutive tube current settings
					 shall not differ by more than 0.10 times their sum:
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where
X1
and
X2
are the average mR/mAs (C/kg/mAs)
						values obtained at each of 2 consecutive tube current settings.
6. 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% of the indicated
					 value.
7. kVp Limitations. Dental
					 x-ray machines with a nominal fixed kVp of less than 50 kVp shall not be used
					 to make diagnostic dental radiographs of humans.
8
Administrative Controls.
a. Patient and film holding devices shall be
					 used when the techniques permit.
b.
					 The tube housing and the PID shall not be hand held during an
					 exposure.
c. The x-ray system shall
					 be operated in such a manner that the useful beam at the patient's skin does
					 not exceed the requirements of 1.6.7(2).
d. Dental fluoroscopy without image
					 intensification shall not be used.