§ 175.48 Specific Requirements for Radiographic X-ray Equipment.
RCNY § 175.48
The requirements of this section apply to all non-dental registrants using diagnostic x-ray equipment.
(a)Acceptance testing. Each registrant must have acceptance testing conducted on all radiographic x-ray units with the exception of dental, podiatric, and bone densitometer units, prior to clinical patient exams being conducted with the designated x-ray units. The acceptance testing must be conducted by a QMP and the report must be provided to the registrant. All non- compliance issues noted in this report must be corrected prior to clinical use of the unit. The acceptance testing report must verify the stated manufacturer's tolerances for all machine testing. If manufacturer tolerances are absent, the registrant's QMP must develop tolerances that must be used in subsequent QA testing by the registrant and must be so noted in the quality assurance manual.
(b)Control and indication of technique factors.
(1)Timers. Means must be provided to terminate the exposure at a preset time interval, a preset product of current and time, a preset number of pulses, or a preset radiation exposure to the image receptor.
(i)Except during serial radiography, the operator must be able to terminate the exposure at any time during an exposure of greater than one-half second. Except during panoramic dental radiography, termination of exposure must cause automatic resetting of the timer to its initial setting or to zero. It must not be possible to make an exposure when the timer is set to a zero or off position if either position is provided.
(ii)During serial radiography, the operator must be able to terminate the x-ray exposure at any time, but means may be provided to permit completion of any single exposure of the series in process.
(2)Automatic exposure controls. When an automatic exposure control is provided: (i) indication must be made on the control panel when this mode of operation is selected; (ii) 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 pulse operation must be equal to or less than a time interval equivalent to two pulses and the minimum exposure time for all other equipment must be equal to or less than 1/60 second or a time interval required to deliver 5 milliampere-seconds (mAs), whichever is greater; (iii) either the product of peak x-ray tube potential, current, and exposure time must be limited to not more than 60 kilowatt-seconds (kWs) per exposure or the product of x-ray tube current and exposure time must be limited to not more than 600 mAs per exposure, except when the x-ray tube potential is less than 51 kVp, in which case the product of x-ray tube current and exposure time must be limited to not more than 2,000 mAs per exposure; and (iv) a visible signal must indicate when an exposure has been terminated at the limits described in subparagraph (iii) of this paragraph, and manual resetting must be required before further automatically timed exposures can be made.
(c)Reproducibility.
(3)Alternatively, the reproducibility of any technique value may be determined by taking 5 consecutive measurements and utilizing the formula given below: Reproducibility = (maximum measured value - minimum measured value) Average of the measured five values The calculated reproducibility shall be equal to ± 10 percent for compliance.
(d)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. In regard to paragraphs (1) through (3) in this subdivision below, measurements can be made in mR instead of mGy.
(e)Field limitation and alignment for mobile, portable, and stationary general purpose x-ray systems. Except when spot-film devices are in service, mobile, portable, and stationary general purpose radiographic x-ray systems must meet the following requirements: (1) Variable x-ray field limitation. A means for stepless adjustment of the size of the x-ray field must be provided. Each dimension of the minimum field size at an SID of 100 cm must be equal to or less than 5 cm.
(iii)The edge of the light field at 100 cm or at the maximum SID, whichever is less, must 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.
(f)Field indication and alignment on stationary general purpose x-ray equipment. Except when spot-film devices are in service, stationary general purpose x-ray systems must meet the following requirements, in addition to those prescribed in subdivision (e) of this section: (1) Means must 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; (2) The beam-limiting device must numerically indicate the field size in the plane of the image receptor to which it is adjusted; (3) Indication of field size dimensions and SIDs must be specified in centimeters or inches and must 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 2 percent of the SID when the beam axis is indicated to be perpendicular to the plane of the image receptor; and (4) Compliance measurements will be made at each SID in common clinical use (such as SIDs of 100, 150, and 200 cm or 36, 40, 48, 72 inches) and with at least one of the commonly used image receptor dimensions (such as nominal image receptor dimensions of 13, 18, 24, 30, 35, 40, and 43 cm or 5, 7, 8, 9, 10, 11, 12, 14, and 17 inches), or at any other specific dimensions at which the beam-limiting device or its associated diagnostic x-ray system is uniquely designed to operate.
(g)Field limitation on x-ray equipment other than general purpose radiographic systems.
(h)Positive beam limitation (PBL). The requirements of this subdivision apply to radiographic systems which contain PBL and which the registrant has not disabled.
(4)Operator initiated undersizing. The PBL system must 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. Each dimension of the minimum field size at an SID of 100 cm must be equal to or less than 5 cm. Return to PBL function as described in paragraph (1) of this subdivision must occur automatically upon any change of image receptor size or SID.
(5)Override of PBL. A capability may be provided for overriding PBL in case of system failure and for servicing the system. This override may be for all SIDs and image receptor sizes. A key must be required for any override capability that is accessible to the operator. It must not be possible to remove the key while PBL is overridden. Each such key switch or key must be clearly and durably labeled as follows: "For X-Ray Field Limitation System Failure". The override capability is considered accessible to the operator if it is referenced in the operator's manual or in other material intended for the operator or if its location is such that the operator would consider it part of the operational controls.
(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.
(j)Radiation from capacitor energy storage equipment. Radiation emitted from the x-ray tube must not exceed: (1) an air kerma of 0.26 microGy (vice 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; and (2) an air kerma of 0.88 mGy (vice 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. 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).
(k)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 must be used for portable x-ray systems, so that the x-ray tube housing assembly need not be hand-held during an exposure.
(l)Conditions of use.
