Section 11-45-119 - Radiographic systems other than fluoroscopic, dental intraoral, or computed tomography systems(a) The useful beam shall be limited to the area of clinical interest. This 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, (e.g., projections from the shutters of the collimator, cone cutting at the corners, or borders at the film's edge). (1) General purpose stationary, mobile, and portable x-ray systems, including veterinary systems installed after the effective date of this chapter: (A) Means shall be provided for independent stepless adjustment of the size of the x-ray field. Each dimension of the minimum field size at an source-image receptor distance of one hundred centimeters shall be equal to or less than five 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 two 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) In addition to the requirements of paragraph (1), all 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 two percent of the source-image receptor distance, and to indicate the source-image receptor distance to within two percent;(B) The beam-limiting device shall indicate numerically the field size in the plane of the image receptor to which it is adjusted; and(C) Indication of field size dimensions and source-image receptor distances 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 which correspond to those indicated by the beam-limiting device to within two percent of the source-image receptor distances when the beam axis is indicated to be perpendicular to the plane of the image receptor.(3) Radiographic equipment designed for only one image receptor size at a fixed source-image receptor distances 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 percent of the source-image receptor distance, 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) Radiographic systems other than those designated in paragraphs (1), (2), and (3), and veterinary systems installed before the effective date of this chapter: (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 two percent of the source-image receptor distance when the axis of the x-ray beam is perpendicular to the plane of the image receptor.(B) Means shall be provided to align the center of the x-ray field with the center of the image receptor to within two percent of the source-image receptor distance, 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.(C) The requirements of subparagraphs (A) and (B) may be met with a system that meets the requirements for a general purpose x-ray system as specified in paragraph (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 source-image receptor distance for which the unit is designed with each such device having clear and permanent markings to indicate the image receptor size and source-image receptor distance 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 source-image receptor distance for which the unit is designed. Permanent, clearly legible markings shall indicate the image receptor size and source-image receptor distance for which each aperture is designed and shall indicate which aperture is in position for use.(b) Radiation exposure control: (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. 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) 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. Termination of an exposure shall cause automatic resetting of the timer to its initial setting or to "zero." (A) When manual exposure control is provided, 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) Exposure of one-half second or less; and(ii) During serial radiography when means shall be provided to permit completion of any single exposure of the series in progress.(B) 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 fifty-one kilovolts peak, 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 clause (ii) shall be equal to or less than one-sixtieth second or a time interval required to deliver five milliamperes-seconds, whichever is greater;(iv) Either the product of peak x-ray tube potential, current, and exposure time shall be limited to not more than sixty kilowatt-seconds per exposure, or the product of x-ray tube current and exposure time shall be limited to not more than six hundred milliamperes-seconds per exposure, except that when the x-ray tube potential is less than fifty-one kilovolts peak, the product of x-ray tube current and exposure time shall be limited to not more than two thousand milliamperes-seconds per exposure; and(v) A visible signal shall indicate when an exposure has been terminated at the limits required by clause (iv), and manual resetting shall be required before further automatically timed exposures can be made.(3) Means shall be provided for visual indication of x-ray production 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.(4) 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 ten percent of the average exposure time (T), when four timer tests are performed: Click Here To View Image
(5) The x-ray exposure control shall be so placed that the operator can view the patient while making any exposure.(6) Operator protection, except veterinary systems: (A) 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.(B) Mobile and portable x-ray systems which are: (i) Used continuously for greater than one week in the same location, i.e., a room or suite shall be considered as stationary systems under subparagraph (A).(ii) Used for less than one week in the same location shall be provided with either a protective barrier at least 6.5 feet (two meters) high for operator protection during exposures, or means shall be provided to allow the operator to be at least twelve feet (3.7 meters) from the tube housing assembly during the exposure.(7) Operators of all stationary, mobile or portable x-ray systems used for veterinary work shall be provided with a 6.5 foot (two meters) high protective barrier for operator protection during exposures, or a means to allow the operator to be at least twelve feet (3.7 meters) from the tube housing assembly during exposures, or a protective apron and protective gloves.(c) All mobile or portable radiographic systems shall be provided with means to limit the source-to-skin distance to equal to or greater than thirty centimeters, except for veterinary systems.(d) When all technique factors are held constant, including control panel selections associated with automatic exposure control systems, the coefficient of variation of exposure for both manual and automatic exposure control systems shall not exceed 0.05. This requirement shall be deemed to have been met if, when four 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 ten percent of the average exposure (E): Click Here To View Image
(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 two milliroentgens (0.516 microcoulombs per kilogram) per hour at five centimeters from any accessible surface of the diagnostic source assembly, with the beam-limiting device fully open.(f) 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 ten percent of the indicated value.(g) Linearity, uncertified x-ray systems only: 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 forty percent to one hundred percent of the maximum rated. (1) Equipment having independent selection of x-ray tube current: The average ratios of exposure to the indicated milliampere seconds product (mR/mAs (or C/kg/mAs)) obtained at any two tube current settings shall not differ by more than 0.10 times their sum: Click Here To View Image
where X1 and X2 are the average mR/mAs (or C/kg/mAs) values obtained at any two tube current settings.
(2) Equipment having a combined x-ray tube current-exposure time product (mAs) selector, but not a separate tube current (mA) selector: The average ratios of exposure to the indicated milliampere seconds product (mR/mAs (or C/kg/mAs)) obtained at any two mAs selector settings shall not differ by more than 0.10 times their sum: Click Here To View Image
where X1 and X2 are the average mR/mAs (or C/kg/mAs) values obtained at any two mAs selector settings.
(3) Determination of compliance shall be based on four 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) Additional requirements applicable to certified systems only: diagnostic x-ray systems incorporating one or more certified component(s) shall be required to comply with the following additional requirement(s) which relate to that certified component(s). (1) Linearity: When the equipment is operated on a power supply as specified by the manufacturer in accordance with the requirements of applicable federal standards, for any fixed x-ray tube potential within the range of forty to one hundred percent of the maximum rated. (A) For equipment having independent selection of x-ray tube current, the average ratios of exposure to the indicated milliampere seconds product obtained at any two consecutive tube current settings shall not differ by more than 0.10 times their sum: Click Here To View Image
where X1 and X2 are the average mR/mAs (C/kg/mAs) values obtained at each of two consecutive tube current settings or at two settings differing by no more than a factor of two where the tube current selection is continuous.
(B) For equipment having selection of x-ray tube current-exposure time product manufactured after May 3, 1994, the average ratios of exposure to the indicated milliampere seconds product obtained at any two consecutive milliampere seconds selector settings shall not differ by more than 0.10 times their sum: Click Here To View Image
where X1 and X2 are the average mR/mAs (C/kg/mAs) values obtained at each of two consecutive milliampere seconds selector settings or at two settings differing by no more than a factor of two where the milliampere seconds selector provides continuous selection.
(2) Beam limitation for stationary and mobile general purpose x-ray systems: (A) There shall be provided a means of stepless adjustment of the size of the x-ray field. The minimum field size at an source-image receptor distance of one hundred centimeters shall be equal to or less than five centimeters by five centimeters.(B) When a light localizer is used to define the x-ray field, it shall provide an average illumination of not less than one hundred sixty lux or fifteen footcandles at one hundred centimeters or at the maximum source-image receptor distance, 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.(C) The edge of the light field at one hundred centimeters or at the maximum source-image receptor distance, whichever is less, shall have a contrast ratio, corrected for ambient lighting, of not less than four in the case of beam-limiting devices designed for use on stationary equipment, and a contrast ratio of not less than three in the case of beam-limiting devices designed for use on mobile equipment. The contrast ratio is defined as I1/I2 where I1 is the illumination three millimeters from the edge of the light field toward the center of the field; and I2 is the illumination three millimeters from the edge of the light field away from the center of the field. Compliance shall be determined with a measuring instrument aperture of one millimeter in diameter.(3) Beam limitation for portable x-ray systems shall meet the beam limitation requirements of paragraphs (1) and (2).(4) Stationary, general purpose x-ray systems which contain a tube housing assembly, an x-ray control, and, for those systems so equipped, a table, all certified in accordance with 21 C.F.R. 1020.30(c) shall have manual collimation for field limitation and alignment.(5) If positive beam limitation is installed on stationary, general purpose x-ray systems after the effective date of these rules, the following requirements shall be met: (A) Positive beam limitation 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 subparagraph (E), from the corresponding image receptor dimensions by more than three percent of the source-image receptor distance; or(ii) The sum of the length and width differences as stated in clause (i) without regard to sign exceeds four percent of the source-image receptor distance.(iii) The beam limiting device is at an source-image receptor distance for which positive beam limitation is not designed for sizing.(B) If a means of overriding the positive beam limitation system exists, that means shall be designed for use only in the event of positive beam limitation system failure or if the system is being serviced.(C) 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, (i) Shall require that a key be utilized to defeat the positive beam limitation;(ii) Shall require that the key remain in place during the entire time the positive beam limitation system is overridden; and(iii) Shall require that the key or key switch be clearly and durably labeled as follows: FOR X-RAY FIELD LIMITATION SYSTEM FAILURE
(D) Compliance with subparagraph (A) shall be determined when the equipment indicates that the beam axis is perpendicular to the plane of the image receptor. 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 an source-image receptor distance of one hundred centimeters shall be equal to or less than five centimeters by five centimeters.(F) Positive beam limitation 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 subparagraph (B), then any change of image receptor size or source-image receptor distance shall cause the automatic return.(6) Except for dental panoramic systems, termination of exposure shall cause automatic resetting of the timer to its initial setting or to "zero."(i) A tube stand or other mechanical support shall be used for portable x-ray systems so that the x-ray tube housing assembly need not be hand-held during exposures.[Eff 11/12/99] (Auth: HRS §§ 321-10, 321-11, 321-71) (Imp: HRS §§ 321-1, 321-11(21), 321-71)