South Carolina Code of Regulations › Chapter 61 - DEPARTMENT OF HEALTH AND ENVIRONMENTAL CONTROL › Subchapter 61-64 - X-Rays (Title B) › Part VI - USE OF THERAPEUTIC EQUIPMENT › Section 61-64.VI.RHB 6.4 - Therapeutic X-ray Systems of Less than 1 MeV

Current through Register Vol. 48, No. 6, June 28, 2024
6.4.1 Equipment
				requirements.
6.4.1.1 Leakage radiation. When
				the tube is operated at its leakage technique factors, the leakage radiation
				shall not exceed the values specified at the distance stated for the
				classification of that x-ray system shown in Table 1.
TABLE 1. LEAKAGE LIMITS FOR THERAPEUTIC X-RAY SYSTEMS OF LESS
				  THAN 1 MeV.
System
Contact Therapy
0-150 kVp (manufactured or
installed prior to January 1, 1994)
Leakage Limit 100 mR/hr
1 R in 1 hr.
Measurement Location
5 cm from surface of tube housing
1 m from source
0-150 kVp (manufactured on or after January 1,
								1994)
100 mR in 1 hr
1 m from source
151-500 kVp 500-999 kVp
1 R in 1 hr
0.1 percent of 1 R in 1 hr.
1 m from source
1 m from source useful beam
6.4.1.2 Permanent Beam-Limiting Devices.
				Permanent fixed diaphragms or cones used for limiting the useful beam shall
				provide the same or a higher degree of protection as required for the tube
				housing assembly.
6.4.1.3 Removable
				and Adjustable Beam-Limiting Device.
6.4.1.3.1
				Removable beam-limiting devices shall, for the portion of the useful beam to be
				blocked by these devices, transmit not more than one percent (1%) of the useful
				beam at the maximum kV and maximum treatment filter. This requirement does not
				apply to auxiliary blocks or materials placed in the useful beam to shape the
				useful beam to the individual patient.
6.4.1.3.2 Adjustable beam-limiting devices
				shall, for the portion of the x-ray beam to be blocked by these devices,
				transmit not more than five percent (5%) of the useful beam at the maximum kV
				and maximum treatment filter.
6.4.1.3.3 Adjustable beam-limiting devices
				installed after May 25, 2001, shall meet the requirements of
				RHB 6.4.1.3.
6.4.1.4 The filter system shall be
				so designed that:
6.4.1.4.1 The filters cannot
				be accidentally displaced at any possible tube orientation;
6.4.1.4.2 For equipment installed after
				January 1, 1994, an interlock system prevents irradiation if the proper filter
				is not in place;
6.4.1.4.3 The
				radiation at five centimeters (5 cm) from the filter insertion slot opening
				does not exceed thirty Roentgens (30 R)(7.74 mC/kg) per hour under any
				operating conditions; and
6.4.1.4.4
				Each filter is marked as to its material of construction and its thickness. For
				wedge filters, the wedge angle shall appear on the wedge or wedge
				tray.
6.4.1.5 Tube
				Immobilization. The tube housing assembly shall be capable of being immobilized
				for stationary treatments.
6.4.1.6
				Focal Spot Marking. The tube housing assembly shall be so marked that it is
				possible to determine the location of the focal spot to within five millimeters
				(5 mm), and such markings shall be readily accessible for use during
				calibration procedures.
6.4.1.7
				Beam Block. Contact therapy tube housing assemblies shall have a removable
				shield of at least 0.5 millimeter lead equivalency at one hundred kilovoltage
				peak (100 kVp) that can be positioned over the entire useful beam exit port
				during periods when the beam is not in use.
6.4.1.8 Beam Monitoring System. Systems of
				greater than one hundred fifty (150 kVp) manufactured after January 1, 1994,
				shall be provided with a beam monitoring system which:
6.4.1.8.1 Shall have the detector of the
				monitor system interlocked to prevent incorrect positioning;
6.4.1.8.2 Shall not allow irradiation until a
				preselected value of exposure has been made at the treatment control
				panel;
6.4.1.8.3 Shall
				independently terminate irradiation when the preselected exposure has been
				reached;
6.4.1.8.4 Shall be so
				designed that, in the event of a system malfunction or electrical power
				failure, the dose administered to a patient prior to the system malfunction or
				power failure can be accurately determined;
6.4.1.8.5 Shall have a display at the control
				panel from which the dose at a reference point in soft tissue can be
				calculated;
6.4.1.8.6 Shall have a
				control panel display which maintains the administered dose reading until
				intentionally reset to zero (0); and
6.4.1.8.7 Shall have a control panel display
				which does not have scale multiplying factors and utilizes a design such that
				increasing dose is displayed by increasing numbers.
6.4.1.9 Timer.
6.4.1.9.1 A timer which has a display shall
				be provided at the treatment control panel. The timer shall have a preset time
				selector.
6.4.1.9.2 The timer shall
				activate with the production of radiation and retain its reading after
				irradiation is interrupted. After irradiation is terminated and before
				irradiation can be reinitiated, it shall be necessary to reset the elapsed time
				indicator to zero (0).
6.4.1.9.3
				The timer shall terminate irradiation when a preselected time has elapsed, if
				any dose monitoring system present has not previously terminated
				irradiation.
6.4.1.9.4 The timer
				shall permit accurate presetting and determination of exposure times as short
				as one (1) second.
6.4.1.9.5 The
				timer shall not permit an exposure if set at zero (0).
6.4.1.9.6 The timer shall not activate until
				the shutter is opened when irradiation is controlled by a shutter mechanism
				unless calibration includes a timer factor to compensate for mechanical
				lag.
6.4.1.9.7 Timers shall be
				accurate to within one percent (1%) of the selected value or one (1) second,
				whichever is greater.
6.4.1.10 Control Panel Functions. The control
				panel, in addition to the displays required in other provisions of this Part,
				shall have:
6.4.1.10.1 An indication of
				whether electrical power is available at the control panel and if activation of
				the x-ray tube is possible;
6.4.1.10.2 An indication of whether x-rays
				are being produced;
6.4.1.10.3
				Means for indicating x-ray tube potential and current;
6.4.1.10.4 Means for terminating an exposure
				at any time;
6.4.1.10.5 A locking
				device which will prevent unauthorized use of the x-ray system; and
6.4.1.10.6 For x-ray systems manufactured
				after May 25, 2001, a positive display of specific filters in the
				beam.
6.4.1.11 Multiple
				Tubes. When a control panel may energize more than one (1) x-ray tube:
6.4.1.11.1 It shall be possible to activate
				only one (1) x-ray tube at any time;
6.4.1.11.2 There shall be an indication at
				the control panel identifying which x-ray tube is activated; and
6.4.1.11.3 There shall be an indication at
				the tube housing assembly when that tube is energized.
6.4.1.12 Source-to-Skin Distance (SSD). There
				shall be means of determining initially the SSD to within one centimeter (1 cm)
				and of producing this measurement to within two millimeters (2 mm)
				thereafter.
6.4.1.13 Shutters.
				Unless it is possible to bring the x-ray output to the prescribed exposure
				parameters within five (5) seconds, the beam shall be attenuated by a shutter
				having a lead equivalency not less than that of the tube housing assembly.
6.4.1.13.1 After the unit is at operating
				parameters, the shutter shall be controlled electrically by the operator from
				the control panel.
6.4.1.13.2 An
				indication of shutter position shall appear on the control panel.