Section R313-30-7 - Therapeutic Radiation Machines - Photon Therapy Systems (500 kV and Above) and Electron Therapy Systems (500 keV and Above)(1) Leakage Radiation Outside the Maximum Useful Beam in Photon and Electron Modes. (a) The absorbed dose rate due to leakage radiation (excluding neutrons) at any point outside the maximum sized useful beam, but within a circular plane of radius two meters which is perpendicular to and centered on the central axis of the useful beam at the nominal treatment distance, that is at the plane of the patient, shall not exceed a maximum of 0.2 percent and an average of 0.1 percent of the absorbed dose rate on the central axis of the beam at the nominal treatment distance. Measurements shall be averaged over an area not exceeding 100 square centimeters at a minimum of 16 points uniformly distributed in the plane;(b) Except for the area defined in R313-30-7(1)(a), the absorbed dose rate, excluding that from neutrons, at one meter from the electron path between the electron source and the target or electron window shall not exceed 0.5 percent of the absorbed dose rate on the central axis of the beam at the nominal treatment distance. Measurements shall be averaged over an area not exceeding 100 square centimeters;(c) For equipment manufactured after the effective date of these rules, the neutron absorbed dose outside the useful beam shall be in compliance with applicable acceptance criteria; and(d) For therapeutic radiation machines, the registrant shall determine, or obtain from the manufacturer, the leakage radiation existing at the positions specified in R313-30-7(1)(a) through R313-30-7(1)(c) for the specified operating conditions. Records on leakage radiation measurements shall be maintained at the installation for inspection by representatives of the Director.(2) Leakage Radiation Through Beam Limiting Devices. (a) Photon Radiation. (i) Adjustable or interchangeable beam limiting devices, such as the collimating jaws or x-ray cones, shall attenuate the useful beam so that at the nominal treatment distance, the maximum absorbed dose anywhere in the area shielded by the beam limiting devices shall not exceed two percent of the maximum absorbed dose on the central axis of the useful beam measured in a ten centimeters by ten centimeters radiation field; and(ii) Interchangeable beam limiting devices, such as auxiliary beam blocking material, shall attenuate the useful beam so that at the nominal treatment distance, the maximum absorbed dose anywhere in the area shielded by the interchangeable beam limiting device shall not exceed five percent of the maximum absorbed dose on the central axis of the useful beam measured in a ten centimeter by ten centimeter radiation field.(b) Electron Radiation. Adjustable or interchangeable electron applicators shall attenuate the radiation, including but not limited to photon radiation generated by electrons incident on the beam limiting device and electron applicator and other parts of the radiation head, so that the absorbed dose in a plane perpendicular to the central axis of the useful beam at the nominal treatment distance shall not exceed: (i) A maximum of two percent of the absorbed dose on the central axis of the useful beam at the nominal treatment distance. This limit shall apply beyond a line seven centimeters outside the periphery of the useful beam; and(ii) A maximum of ten percent of the absorbed dose on the central axis of the useful beam at the nominal treatment distance. This limit shall apply beyond a line two centimeters outside the periphery of the useful beam.(c) Measurement of Leakage Radiation. (i) Photon Radiation. Measurements of leakage radiation through the beam limiting devices shall be made with the beam limiting devices closed and residual apertures blocked by at least two tenth value layers of suitable absorbing material. In the case of overlapping beam limiting devices, the leakage radiation through the sets of beam limiting devices shall be measured independently at the depth of maximum dose. Measurements shall be made using a radiation detector of area not exceeding ten square centimeters;(ii) Electron Radiation. Measurements of leakage radiation through the electron applicators shall be made with an appropriate radiation detector suitably protected against radiation which has been scattered from material beyond the radiation detector. Measurements shall be made using an appropriate amount of water equivalent build up material for the energies being measured.(3) Filters and Wedges. (a) Filters and wedges which are removable from the system shall be clearly marked with an identification number; (i) For removable wedge filters, the nominal wedge angle shall appear on the wedge, or on the wedge tray if the wedge filter is permanently mounted to the tray.(ii) If the wedge or wedge tray is damaged, the Radiation Therapy Physicist will decide if the wedge transmission factor shall be redetermined;(b) For equipment manufactured after the effective date of these rules which utilize a system of wedge filters: (i) Irradiation shall not be possible until a selection of a wedge filter or a positive selection to use "no wedge filter" has been made at the treatment control panel;(ii) An interlock system shall be provided to prevent irradiation if the wedge filter selected is not in the correct position;(iii) A display shall be provided at the treatment control panel showing the wedge filters in use; and(iv) An interlock shall be provided to prevent irradiation if a wedge filter selection operation, either manual or automatic, carried out in the treatment room does not agree with the wedge filter selection operation carried out at the treatment control panel.(c) If the absorbed dose rate information required by R313-30-7(8) relates exclusively to operation with a field flattening filter or beam scattering foil in place, the filter or foil shall be removable only by the use of tools. If removable, the filter or foil shall be interlocked to prevent incorrect selection and incorrect positioning.(d) For equipment manufactured after the effective date of these rules which utilize a system of interchangeable field flattening filters or interchangeable beam scattering foils: (i) An interlock system shall be provided to prevent irradiation if the appropriate flattening filter for the x-ray energy selected is not in the correct position in the beam;(ii) An interlock system shall be provided to prevent irradiation if the appropriate beam scattering foil for the electron energy selected is not in the correct position in the beam;(iii) An interlock system shall be provided to prevent irradiation if no scattering foil is in place for the electron beams, or if no flattening filter is in place for the x-ray beams; and(iv) A display shall be provided at the treatment control panel showing a fault indicator when the interlock system has prevented irradiation. The fault indicator will identify a filter or foil error.(4) Stray Radiation in the Useful Beam. For equipment manufactured after the effective date of these rules, the registrant shall determine during acceptance testing, or obtain from the manufacturer, data sufficient to ensure that x-ray stray radiation in the useful electron beam, absorbed dose at the surface during x-ray irradiation and stray neutron radiation in the useful x-ray beam meet applicable acceptance criteria.(5) Beam Monitors. Therapeutic radiation machines subject to R313-30-7 shall be provided with redundant beam monitoring systems. The sensors for these systems shall be fixed in the useful beam during treatment to indicate the dose monitor unit rate, and to monitor other beam parameters. (a) Equipment manufactured after the effective date of these rules shall be provided with at least two independently powered integrating dose meters. Alternatively, common elements may be used if the production of radiation is terminated upon failure of a common element.(b) Equipment manufactured on or before the effective date of these rules shall be provided with at least one radiation detector. This detector shall be incorporated into a useful beam monitoring system;(c) The detector and the system into which that detector is incorporated shall meet the following requirements: (i) Detectors shall be removable only with tools and, if movable, shall be interlocked to prevent incorrect positioning;(ii) Detectors shall form part of a beam monitoring system from whose readings in dose monitor units the absorbed dose at a reference point can be calculated;(iii) The beam monitoring systems shall be capable of independently monitoring, interrupting, and terminating irradiation; and(iv) For equipment manufactured after the effective date of these rules, the design of the beam monitoring systems shall ensure that the: (A) Malfunctioning of one system shall not affect the correct functioning of the secondary system; and(B) Failure of an element common to both systems which could affect the correct function of both systems shall terminate irradiation or prevent the initiation of radiation.(v) Beam monitoring systems shall have a legible display at the treatment control panel. For equipment manufactured after the effective date of these rules, displays shall: (A) Maintain a reading until intentionally reset;(B) Have only one scale and no electrical or mechanical scale multiplying factors;(C) Utilize a design so that increasing dose monitor units are displayed by increasing numbers; and(D) In the event of power failure, the dose monitor units delivered up to the time of failure, or the beam monitoring information required in R313-30-7(5)(c)(v)(C) displayed at the control panel at the time of failure shall be retrievable in at least one system for a 20 minute period of time.(6) Beam Symmetry. (a) Bent-beam linear accelerators subject to R313-30-7 shall be provided with auxiliary devices to monitor beam symmetry;(b) The devices referenced in R313-30-7(6)(a) shall be able to detect field asymmetry greater than ten percent; and(c) The devices referenced in R313-30-7(6)(a) shall be configured to terminate irradiation if the specifications in R313-30-7(6)(b) can not be maintained.(7) Selection and Display of Dose Monitor Units. (a) Irradiation shall not be possible until a selection of a number of dose monitor units has been made at the treatment control panel;(b) The preselected number of dose monitor units shall be displayed at the treatment control panel until reset manually for the next irradiation;(c) After termination of irradiation, it shall be necessary to reset the dosimeter display before subsequent treatment can be initiated; and(d) For equipment manufactured after the effective date of these rules, after termination of irradiation, it shall be necessary for the operator to reset the preselected dose monitor units before irradiation can be initiated.(8) Air Kerma Rate and Absorbed Dose Rate. For equipment manufactured after the effective date of these rules, a system shall be provided from whose readings the air kerma rate or absorbed dose rate at a reference point can be calculated. The radiation detectors specified in R313-30-7(5) may form part of this system. In addition: (a) The dose monitor unit dose rate shall be displayed at the treatment control panel;(b) If the equipment can deliver an air kerma rate or absorbed dose rate at the nominal treatment distance more than twice the maximum value specified by the manufacturer, a device shall be provided which terminates irradiation when the air kerma rate or absorbed dose rate exceeds a value twice the specified maximum. The dose rate at which the irradiation will be terminated shall be a record maintained by the registrant;(c) If the equipment can deliver, under any fault condition, an air kerma rate or absorbed dose rate at the nominal treatment distance more than ten times the maximum value specified by the manufacturer, a device shall be provided to prevent the air kerma rate or absorbed dose rate anywhere in the radiation field from exceeding twice the specified maximum value and to terminate irradiation if the excess absorbed dose at the nominal treatment distance exceeds 4 Gy (400 rad); and(d) For therapeutic radiation machines, the registrant shall determine, or obtain from the manufacturer, the maximum values specified in R313-30-7(8)(b) and R313-30-7(8)(c) for the specified operating conditions. Records of these maximum values shall be maintained at the installation for inspection by representatives of the Director.(9) Termination of Irradiation by the Beam Monitoring System or Systems During Stationary Beam Radiation Therapy. (a) Primary systems shall terminate irradiation when the preselected number of dose monitor units has been detected by the system;(b) If the original design of the equipment included a secondary dose monitoring system, that system shall be capable of terminating irradiation when not more than 15 percent or 40 dose monitor units above the preselected number of dose monitor units set at the control panel has been detected by the secondary dose monitoring system; and(c) For equipment manufactured after the effective date of these rules, an indicator on the control panel shall show which monitoring system has terminated irradiation.(10) Termination Switches. It shall be possible to terminate irradiation and equipment movement or go from an interruption condition to termination condition at any time from the operator's position at the treatment control panel.(11) Interruption Switches. If a therapeutic radiation machine has an interrupt mode, it shall be possible to interrupt irradiation and equipment movements at any time from the treatment control panel. Following an interruption, it shall be possible to restart irradiation by operator action without a reselection of operating conditions. If a change is made of a pre-selected value during an interruption, irradiation and equipment movements shall be automatically terminated.(12) Timer. A suitable irradiation control device shall be provided to terminate the irradiation after a preset time interval. (a) A timer shall be provided which has a display at the treatment control panel. The timer shall have a preset time selector and an elapsed time indicator;(b) The timer shall be a cumulative timer which activates with an indication of "BEAM-ON" and retains its reading after irradiation is interrupted or terminated. After irradiation is terminated and before irradiation can be reinitiated, it shall be necessary to reset the elapsed time indicator;(c) The timer shall terminate irradiation when a preselected time has elapsed, if the dose monitoring systems have not previously terminated irradiation.(13) Selection of Radiation Type. Equipment capable of both x-ray therapy and electron therapy shall meet the following additional requirements: (a) Irradiation shall not be possible until a selection of radiation type (x-rays or electrons) has been made at the treatment control panel;(b) The radiation type selected shall be displayed at the treatment control panel before and during irradiation;(c) An interlock system shall be provided to ensure that the equipment can principally emit only the radiation type which has been selected;(d) An interlock system shall be provided to prevent irradiation with x-rays, except to obtain a verification film, when electron applicators are fitted;(e) An interlock system shall be provided to prevent irradiation with electrons when accessories specific for x-ray therapy are fitted; and(f) An interlock system shall be provided to prevent irradiation if selected operations carried out in the treatment room do not agree with the selected operations carried out at the treatment control panel.(14) Selection of Energy. Equipment capable of generating radiation beams of different energies shall meet the following requirements: (a) Irradiation shall not be possible until a selection of energy has been made at the treatment control panel;(b) The nominal energy value selected shall be displayed at the treatment control panel before and during irradiation; and(c) Irradiation shall not be possible until the appropriate flattening filter or scattering foil for the selected energy is in its proper location.(15) Selection of Stationary Beam Radiation Therapy or Moving Beam Radiation Therapy. Therapeutic radiation machines capable of both stationary beam radiation therapy and moving beam radiation therapy shall meet the following requirements: (a) Irradiation shall not be possible until a selection of stationary beam radiation therapy or moving beam radiation therapy has been made at the treatment control panel;(b) The mode of operation shall be displayed at the treatment control panel;(c) An interlock system shall be provided to ensure that the equipment can operate only in the mode which has been selected;(d) An interlock system shall be provided to prevent irradiation if a selected parameter in the treatment room does not agree with the selected parameter at the treatment control panel;(e) Moving beam radiation therapy shall be controlled to obtain the selected relationships between incremental dose monitor units and incremental angle of movement. For equipment manufactured after the effective date of these rules: (i) An interlock system shall be provided to terminate irradiation if the number of dose monitor units delivered in increments of ten degrees of rotation or one centimeter of motion differs by more than 20 percent from the selected value;(ii) Where angle terminates the irradiation in moving beam radiation therapy, the dose monitor units shall differ by less than five percent from the dose monitor unit value selected;(iii) An interlock shall be provided to prevent motion of more than five degrees or one centimeter beyond the selected limits during moving beam radiation therapy;(iv) For equipment manufactured after the effective date of these rules, an interlock shall be provided to require that a selection of direction be made at the treatment control panel in units which are capable of both clockwise and counter-clockwise moving beam radiation therapy.(v) Moving beam radiation therapy shall be controlled with both primary position sensors and secondary position sensors to obtain the selected relationships between incremental dose monitor units and incremental movement.(f) Where the beam monitor system terminates the irradiation in moving beam radiation therapy, the termination of irradiation shall be as required by R313-30-7(9); and(g) For equipment manufactured after the effective date of these rules, an interlock system shall be provided to terminate irradiation if movement: (i) Occurs during stationary beam radiation therapy; or(ii) Does not start or stops during moving beam radiation therapy unless the stoppage is a preplanned function.(16) Facility Design Requirements for Therapeutic Radiation Machines Operating above 500 kV. In addition to shielding adequate to meet requirements of R313-30-9, the following design requirements are made: (a) Protective Barriers. Protective barriers shall be fixed, except for access doors to the treatment room or movable beam interceptors;(b) Control Panel. In addition to other requirements specified in R313-30, the control panel shall also: (i) Be located outside the treatment room;(ii) Provide an indication of whether electrical power is available at the control panel and if activation of the radiation is possible;(iii) Provide an indication of whether radiation is being produced; and(iv) Include an access control device which will prevent unauthorized use of the therapeutic radiation machine;(c) Viewing Systems. Windows, mirrors, closed-circuit television or an equivalent viewing system shall be provided to permit continuous observation of the patient following positioning and during irradiation and shall be so located that the operator may observe the patient from the treatment control panel. The therapeutic radiation machine shall not be used for patient irradiation unless at least one viewing system is operational;(d) Aural Communications. Provision shall be made for continuous two-way aural communication between the patient and the operator at the control panel. The therapeutic radiation machine shall not be used for irradiation of patients unless continuous two-way aural communication is possible;(e) Room Entrances. Treatment room entrances shall be provided with warning lights in a readily observable position near the outside of access doors, which will indicate when the useful beam is "ON;"(f) Entrance Interlocks. Interlocks shall be provided so that access controls are activated before treatment can be initiated or continued. If the radiation beam is interrupted by an access control, it shall not be possible to restore the machine to operation without closing the door and reinitiating irradiation by manual action at the control panel;(g) Beam Interceptor Interlocks. If the shielding material in a protective barrier requires the presence of a beam interceptor to ensure compliance with R313-30-301(1), interlocks shall be provided to prevent the production of radiation, unless the beam interceptor is in place, whenever the useful beam is directed at the designated barriers;(h) Emergency Cutoff Switches. At least one emergency power cutoff switch shall be located in the radiation therapy room and shall terminate equipment electrical power including radiation and mechanical motion. This switch is in addition to the termination switch required by R313-30-7(11). Emergency power cutoff switches shall include a manual reset so that the therapeutic radiation machine cannot be restarted from the unit's control panel without resetting the emergency cutoff switch. Alternatively, power cannot be restarted without pressing a RESET button in the treatment room after resetting the power breaker, and the operator shall check the treatment room and patient prior to turning the power back on;(i) Safety Interlocks. Safety interlocks shall be designed so that defects or component failures in the safety interlock system prevent or terminate operation of the therapeutic radiation machine; and(j) Surveys for Residual Radiation. Surveys for residual activity shall be conducted on therapeutic radiation machines capable of generating photon and electron energies above 10 MV prior to machining, removing, or working on therapeutic radiation machine components which may have become activated due to photo-neutron production.(17) Radiation Therapy Physicist Support. (a) The services of a Radiation Therapy Physicist shall be required in facilities having therapeutic radiation machines with energies of 500 kV and above. The Radiation Therapy Physicist shall be responsible for: (i) Full calibrations required by R313-30-7(19) and protection surveys required by R313-30-4(1);(ii) Supervision and review of dosimetry;(iii) Beam data acquisition and transfer for computerized dosimetry, and supervision of its use;(iv) Quality assurance, including quality assurance check review required by R313-30-7(20)(e) of these rules;(v) Consultation with the authorized user in treatment planning, as needed; and(vi) Perform calculations and assessments regarding misadministrations.(b) If the Radiation Therapy Physicist is not a full-time employee of the registrant, the operating procedures required by R313-30-7(18) shall also specifically address how the Radiation Therapy Physicist is to be contacted for problems or emergencies, as well as the specific actions to be taken until the Radiation Therapy Physicist can be contacted.(18) Operating Procedures. (a) No individual, other than the patient, shall be in the treatment room during treatment or during an irradiation for testing or calibration purposes;(b) Therapeutic radiation machines shall not be made available for medical use unless the requirements of R313-30-4(1), R313-30-7(19) and R313-30-7(20) have been met;(c) Therapeutic radiation machines, when not in operation, shall be secured to prevent unauthorized use;(d) If a patient must be held in position during treatment, mechanical supporting or restraining devices shall be used;(e) A copy of the current operating and emergency procedures shall be maintained at the therapeutic radiation machine control console; and(f) When adjustable beam limiting devices or beam limiting devices that do not contact the skin are used, the position and shape of the radiation field shall be indicated by a light field.(19) Full Calibration Measurements. (a) Full calibration of a therapeutic radiation machine subject to R313-30-7 shall be performed by, or under the direct supervision of, a Radiation Therapy Physicist: (i) Before the first medical use following installation or reinstallation of the therapeutic radiation machine;(ii) Annually. The intervals should not exceed 12 months and shall not exceed 13 months; and(iii) Before medical use under the following conditions: (A) Whenever quality assurance check measurements indicate that the radiation output differs by more than five percent from the value obtained at the last full calibration and the difference cannot be easily reconciled; and(B) Following component replacement, major repair, or modification of components, if the appropriate Quality Assurance checks demonstrate that the characteristics of the radiation beam have been significantly affected as determined by a Radiation Therapy Physicist. The Quality Assurance checks shall be performed by, or under the direct supervision of a Radiation Therapy Physicist. The determination of the need for a full calibration shall be made by a Radiation Therapy Physicist.(iv) Notwithstanding the requirements of R313-30-7(19)(a)(iii): (A) Full calibration of therapeutic radiation machines with multi-energy and multi-mode capabilities is required only for those modes and energies that are not within their range and the difference cannot be easily reconciled; and(B) If the repair, replacement or modification does not affect all modes and energies, full calibration shall be performed on the effected mode or energy if the Quality Assurance checks demonstrate that the characteristics of the radiation beam have been significantly affected as determined by a Radiation Therapy Physicist. The Quality Assurance checks shall be performed by, or under the direct supervision of, a Radiation Therapy Physicist. The determination of the need for a full calibration shall be made by a Radiation Therapy Physicist. The remaining energies or modes may be validated with quality assurance check procedures against the criteria in R313-30-7(19)(a)(iii)(A).(b) To satisfy the requirement of R313-30-7(19)(a), full calibration shall include measurements required for annual calibration by American Association of Physicists in Medicine (AAPM) Report 46, "Comprehensive Quality Assurance for Radiation Oncology," 1994 ed., which is adopted and incorporated by reference;(c) The registrant shall use the dosimetry system described in R313-30-8(6) to measure the radiation output for one set of exposure conditions. The remaining radiation measurements required in R313-30-7(19)(b) may then be made using a dosimetry system that indicates relative dose rates; and(d) The registrant shall maintain a record of calibrations for the duration of the registration. The record shall include the date of the calibration, the manufacturer's name, model number, and serial number for the therapeutic radiation machine, the model numbers and serial numbers of the instruments used to calibrate the therapeutic radiation machine, and the signature of the Radiation Therapy Physicist responsible for performing the calibration.(20) Periodic Quality Assurance Checks. (a) Periodic quality assurance checks shall be performed on therapeutic radiation machines subject to R313-30-7. These checks should be performed at intervals not to exceed those intervals recommended in American Association of Physicists in Medicine (AAPM) Report 46, "Comprehensive Quality Assurance for Radiation Oncology," 1994 ed., which is adopted and incorporated by reference. (i) Determination of parameters for central axis radiation output shall be done at least weekly. The interval shall not exceed ten days.(ii) The interval at which periodic quality assurance checks are to be performed shall be determined by the Radiation Therapy Physicist and shall be documented in the registrant's quality management program. The interval for a specific performance check may be based on the history of that performance check for a particular machine. The interval may be increased above the recommended limits only if the Radiation Therapy Physicist determines the increase is justified based on the history of the performance check for that machine or a machine of the same manufacturer and the same model.(iii) If the performance check demonstrates a need to decrease the interval, the Radiation Therapy Physicist shall decide if the interval should be decreased. The decreased interval shall be continued until the performance check demonstrates that the decreased interval is not necessary.(b) To satisfy the requirement of R313-30-7(20)(a), quality assurance checks shall include determination of central axis radiation output and shall include a representative sampling of periodic quality assurance checks contained in American Association of Physicists in Medicine (AAPM) Report 46, "Comprehensive Quality Assurance for Radiation Oncology," 1994 ed., which is adopted and incorporated by reference. (i) A representative sampling shall include those referenced periodic quality assurance checks necessary to assure that the radiation beam and alignment parameters for all therapy machines and modes of operation are within limits prescribed by AAPM Report 46.(ii) The intervals for a representative sampling of referenced periodic quality assurance checks should not exceed 12 consecutive months and shall not exceed 13 consecutive months.(c) The registrant shall use a dosimetry system which has been inter-compared semi-annually. The intervals should not exceed six months and shall not exceed seven months, with a dosimetry system described in R313-30-8(6)(a) to make the periodic quality assurance checks required in R313-30-7(20)(a)(i);(d) The registrant shall perform periodic quality assurance checks required by R313-30-7(20)(a) in accordance with procedures established by the Radiation Therapy Physicist;(e) The registrant shall review the results of periodic radiation output checks according to the following procedures: (i) The authorized user and Radiation Therapy Physicist shall be immediately notified if a parameter is not within its acceptable range. The therapeutic radiation machine shall not be made available for subsequent medical use until the Radiation Therapy Physicist has determined that all parameters are within their acceptable range;(ii) If periodic radiation output check parameters appear to be within their acceptable range, the periodic radiation output check shall be reviewed and signed by either the authorized user or Radiation Therapy Physicist within two weeks;(iii) The Radiation Therapy Physicist shall review and sign the results of radiation output quality assurance checks at intervals not to exceed one month; and(iv) Other Quality Assurance checks shall be reviewed at intervals specified in the Quality Management Program, as required by R313-30-5.(f) Therapeutic radiation machines subject to R313-30-7 shall have safety quality assurance checks of external beam radiation therapy facilities performed weekly at intervals not to exceed ten days;(g) To satisfy the requirement of R313-30-7(20)(f), safety quality assurance checks shall ensure proper operation of: (i) Electrical interlocks at external beam radiation therapy room entrances;(ii) Proper operation of the "BEAM-ON", interrupt and termination switches;(iii) Beam condition indicator lights on the access doors, control console, and in the radiation therapy room;(iv) Viewing and aural communication systems;(v) Electrically operated treatment room doors from inside and outside the treatment room;(vi) At least one emergency power cutoff switch. If more than one emergency power cutoff switch is installed and not all switches are tested at once, switches shall be tested on a rotating basis. Safety quality assurance checks of the emergency power cutoff switches may be conducted at the end of the treatment day in order to minimize possible stability problems with the therapeutic radiation machine.(h) The registrant shall promptly repair a system identified in R313-30-7(20)(g) that is not operating properly; and(i) The registrant shall maintain a record of quality assurance checks required by R313-30-7(20)(a) and R313-30-7(20)(g) for three years. The record shall include the date of the quality assurance check, the manufacturer's name, model number, and serial number for the therapeutic radiation machine, the manufacturer's name, model number and serial number of the instruments used to measure the radiation output of the therapeutic radiation machine, and the signature of the individual who performed the periodic quality assurance check.Utah Admin. Code R313-30-7