Section 325.5405. X-ray equipment.

Rule 405.  (1) All x-ray tube housings in fixed radiographic installations shall be of the diagnostic type.

(2)  The aluminum equivalent of the total filtration in the useful beam shall not be less than the values shown in table 1.

TABLE 1

Operating kVp       Minimum Total Filter (Inherent plus added)

Below 50 kVp       0.5 mm aluminum

50-70 kVp                             1.5 mm aluminum

Above 70 kVp       2.5 mm aluminum

(3)        Beam-limiting devices (diaphragms, cones, adjustable collimators) capable of restricting the useful beam to the area radiographically recorded shall be provided to define the beam and shall provide the same degree of attenuation as that required of the tube housing.

(4)   Beam-limiting devices shall be calibrated in terms of the size of the projected useful beam at specified source-image distances (SID). This calibration shall be clearly and permanently recorded on the beam-limiting device. Calibration of adjustable beam-limiting devices  shall   permit reproducible settings.

(5)  X-ray systems designed for only 1 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 not 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 2% of the SID.

(6)    General purpose radiographic x-ray systems should be equipped with adjustable beam-limiting devices containing light localizers that define the entire field. Rectangular beam- limiting devices are usually preferable.

(7)   The size of the x-ray beam projected by fixed aperture beam-limiting devices, except those used for stereoradiography, shall not exceed the dimensions of the image receptor by more than 2% of the SID when the axis of the x-ray beam is perpendicular to the plane of the image receptor.

(8)   The calibrated field size indicator on adjustable beam-limiting devices shall be accurate to within 2% of the SID. The light field shall be aligned with the x-ray field with the same degree of accuracy. The field size projected by automatic adjustable beam-limiting  devices shall  provide the same precision.

(9)   For radiographic procedures resulting in multiple views on a single x-ray film the beam-limiting device shall limit the x-ray field size to the recorded radiographic image size within 2% of the SID. Covering a portion of the radiographic film with radio-opaque material is not a substitute for proper x-ray field limitation. This subrule does not apply to spotfilm devices manufactured before the effective date of these rules.

(10)   A device shall be provided which terminates the exposure at a preset time interval or exposure  limit.     The  operator  shall  be   able  to  terminate   the  exposure  at  any  time   by

discontinuing   pressure    upon   the    exposure    switch except that during   serial   radiography means  may be provided   to  permit completion of any single exposure of the series in progress.

(11)   A primary radiographic exposure switch shall be provided which shall be securely fixed such that the operator is required to be behind a fixed shield which will intercept the useful beam and any radiation which has  been scattered only once.

(12)   An auxiliary foot switch may be provided to activate the radiographic tube in addition to but not in substitution of the requirement of subrule (11). This auxiliary switch need not be fastened behind a fixed shield.

(13)   The control panel shall provide positive visual identification of the production of x- rays whenever the x-ray tube is  energized.   A  milliammeter may comply with this subrule.

(14)   On diagnostic x-ray systems manufactured after the effective date of these rules, a signal  audible  to  the  operator  shall  indicate that the exposure has ended.

(15)    The technique factors to be used during an exposure shall be indicated before the exposure begins, except when automatic exposure controls are used, in which case the technique factors which are set before the exposure shall be indicated. On equipment having fixed technique factors, this requirement may be met by permanent markings. Indication of technique factors  shall  be visible from the operator's position.

(16)   X-ray equipment installed after the effective date of these  rules shall be installed and used in accord with the appropriate portions of the 1975 national electrical code (NFPA No. 70-1975) reproduced or referenced in rule 359. X-ray equipment installed before the effective date of these rules shall conform with the appropriate national electrical code in effect at  the time of installation.

History: 1979 AC.