Section He-P 4047.06 - Therapeutic Radiation Machines of Less Than 500 kV(a) When the x-ray tube is operated at its maximum rated tube current for the maximum kV, the leakage air kerma rate shall not exceed the value specified at the distance specified as follows: (1) For 5 to 50 kV systems, the leakage air kerma rate measured at any position 5 centimeters from the tube housing assembly shall not exceed 1 mGy (100 mrad) in any one-hour period;(2) For >50 and <500 kV systems: a. The leakage air kerma rate measured at a distance of 1 meter from the target in any direction shall not exceed 1 cGy (1 rad) in any one-hour period;b. This air kerma rate measurement may be averaged over areas no larger than 100 square centimeters; andc. The air kerma rate at a distance of 5 centimeters from the surface of the tube housing assembly shall not exceed 30 cGy (30 rad) per hour;(3) For each therapeutic radiation machine, the registrant shall determine, or obtain from the manufacturer, the leakage radiation existing at the positions specified in He-P 4047.06(a) (1) and (a) (2), for the specified operating conditions; and(4) Records on leakage radiation measurements shall be maintained after installation for inspection by DHHS/RHS.(b) Permanent diaphragms or cones used for limiting the useful beam shall provide at least the same degree of attenuation as required for the tube housing assembly.(c) All adjustable or removable beam limiting devices, diaphragms, cones or blocks shall meet the following requirements: (1) None shall transmit more than 5 percent of the useful beam for the most penetrating beam used; and(2) When adjustable or removable beam limiting devices are used, the position and shape of the radiation field shall be indicated by a light beam.(d) The filter system shall be so designed that:(1) Filters can not be accidentally displaced at any possible tube orientation;(2) An interlock system prevents irradiation if the proper filter is not in place;(3) The air kerma rate escaping from the filter slot shall not exceed 1 cGy (1 rad) per hour at one meter under any operating conditions; and(4) Each filter shall be marked as to its material of construction and its thickness.(e) The x-ray tube shall be so mounted that it can not accidentally turn or slide with respect to the housing aperture.(f) The tube housing assembly shall be capable of being immobilized for stationary portal treatments.(g) The tube housing assembly shall be marked so that: (1) It is possible to determine the location of the source to within 5 millimeters; and(2) Such marking shall be readily accessible for use during calibration procedures.(h) Contact therapy tube housing assemblies shall have a removable shield of material, equivalent in attenuation to 0.5 millimeters of lead at 100 kV, which can be positioned over the entire useful beam exit port during periods when the beam is not in use.(i) A timer control device shall be provided to terminate the irradiation after a pre-set time interval and shall: (2) Be provided at the treatment control;(3) Have a pre-set time selector;(4) Have elapsed time or time remaining indicator;(5) Be a cumulative timer which activates with an indication of "BEAM-ON" and retains its reading after irradiation is interrupted or terminated;(6) Be able to reset the elapsed time indicator after irradiation is terminated and before irradiation can be re-initiated;(7) Terminate irradiation when a pre-selected time has elapsed, if any dose monitoring system present has not previously terminated irradiation;(8) Permit accurate pre-setting and determination of exposure times as short as 1 second;(9) Not permit an exposure if set at zero;(10) Not activate until the shutter is opened when irradiation is controlled by a shutter mechanism unless calibration includes a timer error correction to compensate for mechanical lag; and(11) Be accurate to within 1 percent of the selected value or 1 second, whichever is greater.(j) The control panel, in addition to the displays required by other provisions in He-P 4047.06, shall have: (1) An indication of whether electrical power is available at the control panel and if activation of the x-ray tube is possible;(2) An indication of whether x-rays are being produced;(3) Means for indicating x-ray tube potential and current;(4) Means for terminating exposure at any time;(5) A locking device which will prevent unauthorized use of the therapeutic radiation machine; and(6) A positive display of specific filter(s) in the beam.(k) A control panel which may energize more than one x-ray tube shall: (1) Activate only one x-ray tube at any time;(2) Have an indication at the control panel identifying which x-ray tube is activated; and(3) Have an indication at the tube housing assembly when that tube is energized.(l) There shall be a means of determining the central axis target-to-skin distance to within 1 centimeter and of reproducing this measurement to within 2 millimeters thereafter.(m) Shutters shall be required as follows: (1) Unless it is possible to bring the x-ray output to the prescribed exposure parameters within 5 seconds after the x-ray "ON" switch is energized, the beam shall be attenuated by a shutter having a lead equivalency not less than that of the tube housing assembly;(2) After the unit is at operating parameters, the shutter shall be controlled by the operator from the control panel; and(3) An indication of shutter position shall appear at the control panel.(n) Each therapeutic radiation machine equipped with a beryllium or other low-filtration window shall: (1) Be clearly labeled as such on the tube housing assembly; and(2) Be provided with a permanent warning device on the control panel that is activated when there is no additional filtration present, in order to indicate that the dose rate is very high.(o) In addition to the shielding requirements of He-P 4047, the treatment room shall meet the following facility design requirements for therapeutic radiation machines capable of operating in the range 50 kV to 500 kV: (1) Provision shall be made for continuous two-way aural communication between the patient and the operator at the control panel; and(2) A viewing system shall: a. Be provided to permit continuous observation of the patient during irradiation;b. Enable the operator to observe the patient from the control panel; andc. Be operational for use of therapeutic radiation machine for patient irradiation.(p) Treatment rooms which contain a therapeutic radiation machine capable of operating above 150 kV shall meet the following additional requirements:(1) All protective barriers shall be fixed except for entrance doors or beam interceptors;(2) The control panel shall be located outside the treatment room or in a totally enclosed booth, which has a shielded ceiling, inside the room;(3) Interlocks shall be provided such that all entrance doors, including doors to any interior booths, shall be closed before treatment can be initiated or continued;(4) If the radiation beam is interrupted by any door opening, it shall not be possible to restore the machine to operation without closing the door and re-initiating irradiation by manual action at the control panel; and(5) When any door referred to in He-P 4047.06(p) is opened while the x-ray tube is activated, the air kerma rate at a distance of 1 meter from the source shall be reduced to less than 1 mGy (100 mrad) per hour.(q) Full calibration of a therapeutic radiation machine shall be performed by, or under the direct supervision of, a radiation therapy physicist and shall meet the following requirements: (1) Full calibration shall be performed as follows: a. Before the first medical use following installation or reinstallation of the therapeutic radiation machine;b. At intervals not exceeding 1 year; andc. Before medical use under the following conditions: 1. Whenever quality assurance check measurements indicate that the radiation output differs by more than 5 percent from the value obtained at the last full calibration and the differences cannot be reconciled; and2. Following any component replacement, major repair, or modification of components that could significantly affect the characteristics of the radiation beam;(2) Notwithstanding the requirements of He-P 4047.06(q) (1) c.1. above: a. Full calibration of therapeutic radiation machines with multi-energy capabilities is required only for those modes and/or energies that are not within their acceptable range;b. If the repair, replacement, or modification does not affect all energies, full calibration shall be performed on the affected energy that is in most frequent clinical use at the facility; andc. Any remaining energies may be validated with quality assurance check procedures against the criteria in He-P 4047.06(q) (1) c.1;(3) For machines with energies greater than or equal to 10 KeV and less than or equal to 40 KeV full calibration shall include all measurements recommended for annual calibration by National Council on Radiation Protection (NCRP) Report 69, "Dosimetry of X-ray and Gamma Ray Beams for Radiation Therapy in the Energy Range 10 KeV to 50 MeV" (1981), which is incorporated by reference and included in Appendix A. For machines with energies greater than or equal to 40 kV and less than equal to 300 kV, full calibration shall include all measurements recommended for annual calibration by "High Dose-Rate Brachytherapy Treatment Delivery" (1998) , AAPM Task Group 59, and "AAPM Protocol for 40-300 kV X-Ray Beam Dosimetry in Radiotherapy and Radiobiology" (2001) by AAPM Task Group 61, both of which are incorporated by reference and included in Appendix A;(4) The registrant shall maintain a record of each calibration for the duration of the registration; and(5) The calibration record shall include: a. The date of the calibration;b. The manufacturer's name, model number, and serial number for both the therapeutic machine and the x-ray tube;c. The model numbers and serial numbers of the instruments used to calibrate the therapeutic radiation machine; andd. The signature of the radiation therapy physicist responsible for performing the calibration.(r) Periodic quality assurance checks shall be performed on therapeutic radiation machines subject to He-P 4047.06, which are capable of operation at greater than or equal to 50 kV, as follows: (1) The registrant shall perform quality assurance checks specified in He-P 4047.06(r) in accordance with written procedures established by the radiation therapy physicist;(2) The quality assurance check procedures required by He-P 4047.06(r) (1) shall specify: a. The frequency at which tests or measurements are to be performed;b. That the quality assurance check be performed during the calibration specified in He-P 4047.06(q) ; andc. The acceptable tolerance for each parameter measured in the quality assurance check, when compared to the value for that parameter determined in the calibration as specified by He-P 4047.06(q) (1) ;(3) The quality assurance check shall investigate the cause for a parameter exceeding a tolerance set by the radiation therapy physicist and correct such parameter before the system is used for patient irradiation;(4) Whenever a quality assurance check indicates a significant change in the operating characteristics of a system, as specified in the radiation therapy physicist's quality assurance check procedures, the system shall be recalibrated as specified by He-P 4047.06(q) (1) ;(5) The registrant shall use the dosimetry system described in He-P 4047.05(k) to make the quality assurance check required in He-P 4047.06(r) (2) ;(6) The registrant shall have the radiation therapy physicist review and sign the results of each radiation output quality assurance check within 30 days of the date that the check was performed;(7) The registrant shall ensure that the safety quality assurance checks of therapeutic radiation machines are performed at intervals not to exceed 30 days;(8) The registrant shall ensure that no therapeutic machine is used to administer radiation to humans unless the quality assurance checks will have been performed within the 30-day period immediately prior to said administration;(9) Safety quality assurance checks shall ensure proper operation of: a. Electrical interlocks at each external beam radiation therapy room entrance;b. Proper operation of the "BEAM-ON" and termination switches;c. Beam condition indicator lights on the access door(s), control console, and in the radiation therapy room;e. If applicable, electrically operated treatment room doors from inside and outside the treatment room;(10) The registrant shall maintain a record of each quality assurance check for 3 years; and(11) The quality assurance check records shall include:a. The date of the quality assurance check;b. The manufacturer's name, model number, and serial number for the therapeutic radiation machine;c. The manufacturer's name, model number, and serial number of the instrument(s) used to measure the radiation output of the therapeutic radiation machine; andd. The signature of the individual who performed the periodic quality assurance check.(s) The following operating procedures shall be met:(1) The therapeutic radiation machine shall not be used for irradiation of patients unless the requirements of He-P 4047.06(q) and He-P 4047.06(r) have been met;(2) Therapeutic radiation machines shall not be left unattended unless secured pursuant to He-P 4047.06(j) (5) ;(3) When a patient must be held in position for radiation therapy, mechanical supporting or restraining devices shall be used;(4) The tube housing assembly shall not be held by an individual during operation unless the assembly is designed to require such holding and the peak tube potential of the system does not exceed 50 kV;(5) If the tube housing is held, the holder shall wear protective gloves and apron of not less than 0.5 millimeters lead equivalency at 100 kV;(6) A copy of the current operating and emergency procedures shall be maintained at the therapeutic radiation machine control console;(7) No individual other than the patient shall be in the treatment room during exposures from therapeutic radiation machines operating above 150 kV; and(8) At energies less than or equal to 150 kV, any individual, other than the patient, in the treatment room shall be protected by a barrier sufficient to meet the requirements of He-P 4020.(t) Each facility location authorized to use a therapeutic radiation machine in accordance with He-P 4047.06 shall: (1) Possess appropriately calibrated portable monitoring equipment;(2) As a minimum, include a portable radiation measurement survey instrument capable of measuring dose rates over the range of 10 µSv (1 mrem) per hour to 10 mSv (1000 mrem) per hour; and(3) Require the survey instrument(s) to be operable and calibrated in accordance with He-P 4047.08.N.H. Admin. Code § He-P 4047.06
#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 #10764, Effective 1/23/2015, Expires7/22/2015.Amended by Volume XXXV Number 32, Filed August 13, 2015, Proposed by #10894, Effective 7/21/2015, Expires 7/21/2025.