NAC459.584. Therapeutic X-ray systems: Filter systems, tube housing.  


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  •      1. The filter system must be designed so that:

         (a) Filters cannot be accidentally displaced from the useful beam at any possible tube orientation.

         (b) Each filter is marked as to its material of construction and its thickness or wedge angle for wedge filters. The filters must be individually distinguishable.

         (c) The operator must be able to determine the presence or absence of each filter and the orientation of each wedge filter in the useful beam when the operator is at his or her position at the control panel either by display at the control panel or by direct observation.

         (d) The filters and filter insertion slot opening must be so designed that the radiation at 5 cm from the filter insertion slot opening does not exceed 30 roentgens per hour under all operating conditions.

         (e) Each machine equipped with a beryllium or other low filtration window must be clearly labeled as such upon the tube head housing and upon the control panel.

         2. The tube housing assembly must be immobilized during stationary treatments.

         3. The tube housing assembly must be marked so that it is possible to determine the location of the focal spot to within 5 millimeters and the marking must be readily accessible for use during calibration procedures.

         4. Contact therapy tube housing assemblies must have a removable shield of 0.5 mm lead equivalency at 100 kVp that must be positioned over the entire useful beam exit port during periods when the beam is not in use.

     [Bd. of Health, Radiation Control Reg. §§ 6.8.1.4-6.8.1.7, eff. 2-28-80]