Section He-P 4046.06 - Radiographic Systems Other Than Fluoroscopic, Dental Intraoral, or Computed Tomography X-ray Systems(a) The useful beam of all radiographic systems except mammographic, fluoroscopic, dental intraoral or computed tomography systems shall be capable of being limited to the area of clinical interest.(b) General purpose stationary and mobile x-ray systems, including veterinary systems, other than portable, shall meet the following: (1) Only x-ray systems provided with means for independent stepless adjustment of at least two dimensions of the x-ray field shall be used;(2) A method shall be provided for visually defining the perimeter of x-ray field;(3) The total misalignment of the edges of the visually defined field compared to the respective edges of the x-ray field shall not exceed 2 percent of the distance from the source to the center of the visually defined field when it is perpendicular to the axis of the x-ray beam;(4) DHHS/RHS may grant non-certified x-ray systems an exemption from the requirements of He-P 4046.06(b) (1), (2), and (3) provided the registrant makes a written application for such exemption, and in that application: a. Demonstrates it is impractical to comply with He-P 4046. 06(b); andb. Describes how the purpose of He-P 4046. 06(b) will be met by other methods;(5) In addition to the requirements of He-P 4046.06(b) (1) -(4), stationary general purpose x-ray systems shall meet the following requirements: a. Methods 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 to the center of the image receptor to not more than 2 percent of the SID;b. The beam-limiting device shall indicate numerically the field size in the plane of the image receptor to which it is adjusted;c. Indication of field size dimensions and SIDs shall be specified in inches and centimeters; andd. X-ray field dimensions in the plane of the image receptor shall correspond to those indicated by the beam-limiting device to not more than 2 percent of the SID when the beam axis is perpendicular to the plane of the image receptor; and(6) X-ray systems designed for only one image receptor size at a fixed SID shall: a. 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; andb. Align the center of the x-ray field with the center of the image receptor to not more than 2 percent of the SID.(c) X-ray systems other than those described in He-P 4046.06, and all veterinary x-ray systems shall meet the following when the axis of the x-ray beam is perpendicular to the plane of the image receptor: (1) Means shall be provided to limit the x-ray field within, and perpendicular to the plane of the image receptor such that the field does not exceed each dimension of the image receptor by more than 2 percent of the SID; and(2) Means shall be provided to align the center of the x-ray field with the center of the image receptor to not more than 2 percent of the SID.(d) Means shall be provided to initiate the radiation exposure only by a deliberate action on the part of the operator.(e) An exposure shall not be possible when the timer is set to a "zero" or "off" position.(f) Means shall be provided for visual indication observable at or from the operator's protected position whenever x-rays are produced.(g) A signal audible to the operator shall indicate that the exposure has terminated.(h) Means shall be provided to terminate the exposure at: (1) A preset time interval or number of pulses;(2) A preset product of current and time; or(3) A preset radiation exposure to the image receptor.(i) Except for dental panoramic systems, termination of an exposure shall cause automatic resetting of the timer to its initial setting or to "zero."(j) An x-ray control shall be incorporated into each x-ray system such that an exposure can be terminated manually, by the operator, at any time except for: (1) Exposures of one-half second or less; or(2) Serial radiography when means shall be provided to permit completion of any single exposure of the series in process.(k) When an automatic exposure control is provided: (1) The control panel shall indicate when this mode of operation is selected;(2) If the x-ray tube potential is equal to or greater than 51 kVp, the minimum exposure time for pulsed operation shall be equal to 2 pulses;(3) The minimum exposure time for all equipment other than specified in He-P 4047. 06(k) (2) shall be no greater than one-sixtieth (1/60) second, or a time interval required to deliver 5 mAs, whichever is greater; and(4) Manual exposure resetting shall be required before further timed exposures can be made.(l) For systems having independent selection of exposure time settings, the average ratios (Xi) of exposure to the indicated timer setting, in units of milliroentgens per second (mR/s), obtained at any two clinically used timer settings shall not differ by more than 0.10 times their sum. This is written as: Click here to view
where X1 and X2 are the average mR/s values.
(m) The x-ray exposure control shall be so placed that the operator can view the patient while making any exposure.(n) Stationary x-ray systems, except veterinary systems, shall be required to have the x-ray control permanently mounted in a protected area that by virtue of shielding or distance or both shall protect the operator during the entire exposure from radiation scatter and is sufficient to comply with the occupational dose limits required by He-P 4020.05.(o) Mobile and portable x-ray systems, except veterinary systems shall meet the requirements of He-P 4046.06(n) if used continuously for greater than one week in the same location, and shall be provided with means to limit the source to skin distance equal to, or greater than 30 centimeters.(p) All stationary, mobile or portable x-ray systems used for veterinary work shall be provided: (1) With a 2 meter (6.5 feet) high protective barrier for operator protection during exposures or(2) With means to allow the operator to be at least 2.7 meters (9 feet) from the tube housing assembly during the exposure.(q) All mobile or portable radiographic systems, except veterinary systems, shall be provided with means to limit the source-to-skin distance to equal to or greater than 30 centimeters.(r) 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.(s) Radiation emitted from the x-ray tube when the system is fully charged and the exposure switch or timer is not activated shall not exceed a rate of 2 milliroentgens per hour (mR/hr) at 5 centimeters from any accessible surface of the diagnostic source assembly, with the beam-limiting device fully open.(t) Deviation of measured technique factors shall: (1) Not exceed 10 percent of the indicated kVP value unless allowed by the manufacturer's written specification; and(2) Not exceed 20 percent of the exposure time, which is either indicated or which can be inferred from known mA or mAs values, unless allowed by the manufacturer's written specification.(u) When equipment having independent selection of x-ray tube current (mA), or a combined x-ray tube current exposure time product (mAs), is operated between 40 percent and 100 percent of the maximum rated kVp, the absolute value of the difference in the ratios (Xi) of exposure to the indicated milliampere-seconds product mR/mAs obtained at any two consecutive tube current settings shall not differ by more than 0.10 times their sum: Click here to view
where the values of X1 and X2 are the average values which are obtained at each of two consecutive tube current settings, or are obtained at two settings differing by no more than a factor of 2 where the tube current selection is continuous.
N.H. Admin. Code § He-P 4046.06
#6827, eff 8-6-98; ss by #8692, INTERIM, eff 7-27-06, EXPIRES: 2-2-07; ss by #8808, eff 1-24-07
Amended byVolume XXXV Number 06, Filed February 12, 2015, Proposed by #10763, Effective 1/23/2015, Expires7/22/2015.Amended by Volume XXXV Number 32, Filed August 13, 2015, Proposed by #10893, Effective 7/21/2015, Expires7/21/2025.