6 Colo. Code Regs. § 1007-1-6.6

Current through Register Vol. 47, No. 11, June 10, 2024

Section 6 CCR 1007-1-6.6 - Requirements for use of general purpose x-ray imaging systems

6.6.1 Administrative controls.

6.6.1.1 The requirements of Section 6.6 apply to all registrants using general diagnostic imaging systems, excluding the following:

(1) Fluoroscopy use which is described in 6.5;

(2) Dental use which is described in 6.7;

(3) Veterinary use which is described in 6.8;

(4) Computed tomography use which is described in 6.9;

(5) Mammography use which is described in 6.10.

6.6.1.2 Certification evaluation (inspection) requirements.

(1) Within 90 days of initial installation:

(a) Digital radiographic systems shall have an initial certification evaluation performed by a RMP;

(b) Non-digital radiographic systems shall have an initial certification evaluation performed by a Qualified Inspector authorized for the specific machine type.

(2) Periodic certification evaluations shall be performed at the frequency specified in Part 2, Section 2.5 by Qualified Inspectors authorized for the specific machine type.

(3) Testing of display monitors which are under the control of the registrant shall be performed by or under the supervision of an RMP in accordance with 6.3.5.6.

(4) Certification evaluations and testing shall follow nationally accepted standards or those recognized by the Department.

6.6.2 Field limitation and alignment for mobile, portable, and stationary general purpose x-ray systems. Mobile, portable, and stationary general purpose radiographic x-ray systems shall meet the following requirements:

6.6.2.1 Variable x-ray field limitation. A means for stepless adjustment of the size of the x-ray field shall be provided.

(1) Each dimension of the minimum field size at an SID of 100 cm shall be equal to or less than 5 cm.

6.6.2.2 Visual definition. Means for visually defining the perimeter of the x-ray field shall be provided.

(1) 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 two (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.

(2) A light localizer used to define the x-ray field of a certified system shall provide illumination sufficient to permit visual determination of the x-ray field under ambient light conditions of up to 500 lux (46 foot candles).

6.6.2.3 Field indication and alignment on stationary general purpose x-ray equipment. Except when spot-image devices are in use, stationary general purpose x-ray systems shall meet the following requirements in addition to those prescribed in 6.6.2.

(1) Means shall be provided to:

(a) Indicate when the axis of the x-ray beam is perpendicular to the plane of the image receptor;

(b) Align the center of the x-ray field with respect to the center of the image receptor to within two (2) percent of the SID; and

(c) Indicate the SID to within two (2) percent.

(2) The beam-limiting device shall indicate numerically the field size in the plane of the image receptor to which it is adjusted.

(3) Indication of field size dimensions and SID's shall be specified in inches and/or cm, 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 two (2) percent of the SID when the beam axis is indicated to be perpendicular to the plane of the image receptor.

(4) 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.

6.6.2.4 Field limitation on x-ray equipment other than general purpose radiographic systems.

(1) X-Ray Systems Designed for One Image Receptor Size.

(a) 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 two (2) percent of the SID; or

(b) Radiographic equipment designed for only one image receptor size at a fixed SID 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.

6.6.2.5 Beam Limitation Requirements for Each X-Ray System Not Governed by 6.6.2.1 through 6.6.2.4:

(1) Which are also designed for use with extraoral image receptors and when used with an extraoral image receptor shall:

(a) Be provided with means 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 two (2) percent of the SID when the axis of the x-ray beam is perpendicular to the plane of the image receptor; and

(b) Be provided with means to align the center of the x-ray field with the center of the image receptor to within two (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.

(2) The requirements of 6.6.2.5(1) may be met with a system that meets the requirements for a general purpose x-ray system as specified in 6.6.2 and 6.6.2.3, or, when alignment means are also provided, may be met with either:

(a) 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

(b) 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.

6.6.2.6 Positive Beam Limitation (PBL). The requirements of 6.6.2.6 shall apply to radiographic systems which contain PBL.

(1) Field size. When a PBL system is provided, it shall prevent x-ray production when:

(a) Either the length or width of the x-ray field in the plane of the image receptor differs from the corresponding image receptor dimension by more than three (3) percent of the SID; or

(b) The sum of the length and width differences as stated in 6.6.2.6(1)(a) without regard to sign exceeds four (4) percent of the SID.

(c) The beam-limiting device is at a SID for which PBL is not designed for sizing.

(2) Conditions for PBL. When provided, the PBL system shall function as described in 6.6.2.6(1) whenever all the following conditions are met:

(a) The image receptor is inserted into a permanently mounted cassette holder;

(b) The image receptor length and width are less than 50 cm;

(c) The x-ray beam axis is within ± three (3) degrees of vertical and the SID is 90 cm to 130 cm inclusive; or the x-ray beam axis is within ± three (3) degrees of horizontal and the SID is 90 cm to 205 cm inclusive;

(d) The x-ray beam axis is perpendicular to the plane of the image receptor to within ± three (3) degrees;

(e) Neither tomographic nor stereoscopic radiography is being performed;

(3) Measuring compliance.

(a) Compliance with the requirements of 6.6.2.6(1) shall be determined when the equipment indicates that the beam axis is perpendicular to the plane of the image receptor and the provisions of 6.6.2.6(2) are met; and

(b) Compliance shall be determined no sooner than 5 seconds after insertion of the image receptor.

(4) Override of PBL.

(a) A capability may be provided for overriding PBL in case of system failure and for servicing the system.

(b) This override may be for all SIDs and image receptor sizes.

(c) A key shall be required for any override capability that is accessible to the operator.

(i) It shall not be possible to remove the key while PBL is overridden.

(ii) Each such key switch or key shall be clearly and durably labeled as follows:

"FOR X-RAY FIELD LIMITATION SYSTEM FAILURE"

(d) The override capability is considered accessible to the operator:

(i) If it is referenced in the operator's manual, or in other materials intended for the operator; or

(ii) If its location is such that the operator would consider it part of the operational controls.

(e) Not be used as a substitute for prompt repair.

(5) Operator initiated undersizing. The PBL system shall be capable of operating such that, at the discretion of the operator, the size of the field may be made smaller than the size of the image receptor through stepless adjustment of the field size.

(a) Each dimension of the minimum field size at an SID of 100 cm shall be equal to or less than 5 cm.

(b) Return to PBL function as described in 6.6.2.6(1) shall occur automatically upon any change of image receptor size or SID.

(6) Disabling of PBL. A facility has the option to permanently functionally disable a PBL system. When this option is chosen, the standards for manual collimation apply.

6.6.3 Radiation Exposure Control.

6.6.3.1 Exposure initiation

(1) 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.

(2) 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.

6.6.3.2 Exposure Indication

(1) Means shall be provided for visual indication observable at or from the operator's protected position whenever x-rays are produced.

(2) In addition, a signal audible to the operator shall indicate that the exposure has terminated.

6.6.3.3 Timers.

(1) 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.

(a) Except during serial radiography, the operator shall be able to terminate the exposure at any time during an exposure of greater than one-half second.

(b) Except during panoramic dental radiography, termination of exposure shall cause automatic resetting of the timer to its initial setting or to "zero".

(c) During serial radiography, the operator shall be able to terminate the x-ray exposure(s) at any time, but means may be provided to permit completion of any single exposure of the series in process.

6.6.3.4 X-ray Control.

(1) Except for only bone densitometry systems, hand-held intraoral systems, each x-ray control shall be located in such a way as to meet the following requirements:

(a) Stationary radiographic systems.

Stationary radiographic systems shall be required to have the x-ray control, including the exposure switch, permanently mounted in a protected (shielded) area so that the operator is required to remain in that protected area during the entire exposure. Design of the operator protected area shall be consistent with Appendix 6B.

(b) Mobile and portable systems.

When any one or combination of mobile or portable x-ray systems are:

(i) Used daily for seven (7) or more consecutive working days in the same location (a room or area), the system(s) shall meet the requirements of a stationary system in 6.6.3.4(1)(a), or the facility shall employ the use of at least one of the items in 6.6.3.4(b)(ii) and establish a written procedure or policy prescribing any limitations necessary to demonstrate that such use will preclude any individual from receiving a dose in excess of the public or occupational dose limits in Part 4 and that such use is consistent with the As Low As Reasonably Achievable (ALARA) concept of Part 4, Section 4.5.2;

(ii) Used daily for less than seven (7) consecutive working days in the same location (a room or area), shall be provided with at least one of the following:

1. A lead-equivalent protective barrier at least 2 meters (more than 6 feet) high for operator protection during exposures; or

2. Means to allow the operator to be at least 2 meters (more than 6 feet) from the patient, x-ray tube and the useful beam during the exposure; or

3. A lead-equivalent protective garment with thyroid shielding.

(c) Podiatry facilities shall meet the protection requirements in 6.6.3.4(1)(b)(ii).

(2) For x-ray equipment capable of displaying technique factors, the technique factors to be used during an exposure shall be indicated before the exposure begins.

(a) When automatic exposure controls are used, the exposure settings that are set prior to the exposure shall be indicated.

(b) On equipment having fixed technique factors, the requirement of 6.6.3.4(2)(a) may be met by having permanent markings on the equipment. Technique factors shall be visible from the operator's position except when performing spot imaging during fluoroscopy.

(c) The accuracy of the indicated kilovoltage peak (kVp) shall meet manufacturer specifications. In the absence of a manufacturer specification, kVp accuracy shall be within ±10 percent.

6.6.3.5 Automatic Exposure Controls. When an automatic exposure control is provided:

(1) Indication shall be made on the control panel when this mode of operation is selected;

(2) When the x-ray tube potential is equal to or greater than 51 kilovolts peak (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 (2) pulses;

(3) The minimum exposure time for all other equipment other than that specified in 6.6.3.5(2) shall be equal to or less than one-sixtieth (1/60) second or a time interval required to deliver 5 miliampere seconds (mAs), whichever is greater;

(4) Either the product of peak x-ray tube potential, current, and exposure time shall be limited to not more than 60 kilowatt-seconds (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 51 kVp, in which case the product of x-ray tube current and exposure time shall be limited to not more than 2000 mAs per exposure; and

(5) A visible signal shall indicate when an exposure has been terminated at the limits required by 6.6.3.5(4), and manual resetting shall be required before further automatically timed exposures can be made.

6.6.3.6 Accuracy.

(1) Deviation of technique factors under Section 6.6.3.3 and 6.6.3.5 from indicated values shall not exceed the limits given by the manufacturer.

(2) If manufacturer specifications are not available, the following criteria shall be used:

(a) The kVp shall not deviate from indicated values by more than ten (10) percent.

(b) The timer accuracy shall not deviate from indicated values by more than:

(i) Ten (10) percent for an indicated time of greater than 20 ms; or

(ii) Fifty (50) percent for an indicated time of 20 ms or less, or 1 pulse, whichever is greater.

6.6.3.7 Reproducibility.

(1) Coefficient of variation. For any specific combination of selected technique factors, the estimated coefficient of variation of the air kerma shall be no greater than 0.05.

(2) Measuring compliance.

(a) Determination of compliance shall be based on 10 (or as otherwise specified in nationally accepted standards) consecutive measurements of air kerma taken within a time period of 1 hour.

(b) Equipment manufactured after September 5, 1978, shall be subject to the additional requirement that all variable controls for technique factors shall be adjusted to alternate settings and reset to the test setting after each measurement.

(c) For equipment having automatic exposure controls, compliance shall be determined with a sufficient thickness of attenuating material in the useful beam such that the technique factors can be adjusted to provide individual exposures of a minimum of 12 pulses on field emission equipment rated for pulsed operations or no less than one-tenth second.

6.6.3.8 Linearity.

The following requirements apply for any fixed x-ray tube potential within the range of 40 percent to 100 percent of the maximum rated value:

(1) For equipment having independent selection of x-ray tube current (mA), the average ratios of air kerma to the indicated milliampere-seconds product (mGy/mAs) obtained at any two consecutive tube current settings shall not differ by more than 0.10 times their sum.

This is:

Click to view image

Where Xi and X2 are the average mGy/mAs values obtained at each of two consecutive mAs selector settings or at two settings differing by no more than a factor of 2 where the mAs selector provides continuous selection.

(2) Equipment having selection of x-ray tube current-exposure time product (mAs).

For equipment manufactured after May 3, 1994, the average ratios of air kerma to the indicated milliampere-seconds product (mGy/mAs) obtained at any two consecutive mAs selector settings shall not differ by more than 0.10 times their sum.

This is:

Click to view image

(3) Measuring compliance.

(a) Determination of compliance will be based on 10 exposures (or as specified in nationally accepted standards), made within 1 hour, at two or more settings over a range of clinically relevant mAs values.

(i) These settings may include any two focal spot sizes except where one is equal to or less than 0.45 mm and the other is greater than 0.45 mm.

(ii) For purposes of this requirement, focal spot size is the focal spot size specified by the x-ray tube manufacturer.

6.6.3.9 Source-Skin Distance.

(1) Each mobile, portable or hand-held radiographic x-ray imaging system shall be provided with means to limit the source-skin distance to equal to or greater than 30 cm.

(2) The minimum source-skin distance shall not be less than 30 cm, excluding dental systems addressed in 6.7, and veterinary systems addressed in 6.8.

6.6.3.10 Exposure Reproducibility.

(1) When all exposure settings are held constant, including control panel selections associated with automatic exposure control systems the coefficient of variation of air kerma for both manual and automatic exposure control systems shall not exceed 0.05.

6.6.3.11 Radiation from Capacitor Energy Storage Equipment.

Radiation emitted from the x-ray tube shall not exceed:

(1) An air kerma of 0.26 microGy (0.03 mR exposure) in 1 minute at 5 cm 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.

(a) Compliance shall be determined by measurements averaged over an area of 100 cm, with no linear dimensions greater than 20 cm; and

(2) An air kerma of 0.88 milliGy (100 mR exposure) in one hour at 100 cm from the x-ray source, with beam-limiting device fully open, when the system is discharged through the x-ray tube either manually or automatically by use of a discharge switch or deactivation of the input power.

(a) Compliance shall be determined by measurements of the maximum air kerma per discharge multiplied by the total number of discharges in 1 hour (duty cycle).

(b) The measurements shall be averaged over an area of 100 square cm with no linear dimension greater than 20 cm.

6.6.4 Tube stands for portable x-ray systems.

Except during veterinary field operations where it is impractical to do so, a tube stand or other mechanical support shall be used for portable x-ray systems that are not intended to be handheld during operation.

6 CCR 1007-1-6.6

Colorado Register, Vol 37, No. 14. July 25, 2014, effective 8/14/2014

38 CR 02, January 25, 2015, effective 2/14/2015

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40 CR 11, June 10, 2017, effective 6/30/2017

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42 CR 24, December 25, 2019, effective 1/14/2020

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