§ 175.65 Therapeutic Radiation Machines above 500 kV.
RCNY § 175.65
This section applies to photon therapy systems capable of operating at 500 kV and above, electron therapy systems capable of operating at 500 keV and above, and proton therapy systems.
(a)Possession of survey instrument. Each facility location authorized to use a therapeutic radiation machine subject to this section must possess appropriately calibrated portable monitoring equipment. At a minimum, such equipment must include a portable radiation measurement survey instrument capable of measuring dose rates over the range 10 µSv (1 mrem) per hour to 10 mSv (1,000 mrem) per hour. The survey instrument must be operable and calibrated in accordance with 24 RCNY Health Code § 175.66.
(b)Leakage radiation outside the maximum useful beam in photon and electron modes.
(1)The absorbed dose due to leakage radiation (excluding neutrons) at any point outside the maximum sized useful beam, but within a circular plane of radius 2 meters which is perpendicular to and centered on the central axis of the useful beam at the nominal treatment distance (i.e. patient plane), must not exceed a maximum of 0.2 percent and an average of 0.1 percent of the absorbed dose on the central axis of the beam at the nominal treatment distance. Measurements must be averaged over an area not exceeding 100 square centimeters (100 cm 2 ) at a minimum of 16 points uniformly distributed in the plane; (2) Except for the area defined in paragraph (1) of this subdivision, the absorbed dose due to leakage radiation (excluding neutrons) at 1 meter from the electron path between the electron source and the target or electron window must not exceed 0.5 percent of the absorbed dose on the central axis of the beam at the nominal treatment distance. Measurements must be averaged over an area not exceeding 100 square centimeters (100 cm 2 ); (3) For equipment manufactured after July 1, 2019, the neutron absorbed dose outside the useful beam must comply with International Electrotechnical Commission (IEC) Document 60601-2-1 (or the most current revision or successor national standard); and (4) For each therapeutic radiation machine, the registrant must determine, or obtain from the manufacturer, the leakage radiation existing at the positions specified in paragraphs (1) and (2) of this subdivision for the specified operating conditions. Records on leakage radiation measurements must be maintained at the installation for inspection by the Department.
(c)Leakage radiation through beam limiting devices.
(2)Electron radiation. All adjustable or interchangeable electron applicators must 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, such that the absorbed dose in a plane perpendicular to the central axis of the useful beam at the nominal treatment distance must not exceed: (i) a maximum of 2 percent and average of 0.5 percent of the absorbed dose on the central axis of the useful beam at the nominal treatment distance. This limit applies beyond a line 7 centimeters outside the periphery of the useful beam; and (ii) a maximum of 10 percent of the absorbed dose on the central axis of the useful beam at the nominal treatment distance. This limit applies beyond a line 2 centimeters outside the periphery of the useful beam.
(3)Skyshine radiation. The exposure due to neutron and photon emissions scattered outside the facility must be calculated using industry standard methods.
(4)Measurement of leakage radiation.
(i)Photon radiation. Measurements of leakage radiation through the beam limiting devices must be made with the beam limiting devices closed and any residual aperture blocked by at least 2-tenth value layers of suitable absorbing material. In the case of overlapping beam limiting devices, the leakage radiation through each set must be measured independently at the depth of maximum dose. Measurements must be made using a radiation detector of area not exceeding 10 square centimeters (10 cm 2 ).
(ii)Electron radiation. Measurements of leakage radiation through the electron applicators must be made with the electron beam directed into the air and using a radiation detector of area up to but not exceeding 1 square centimeter suitably protected against radiation which has been scattered from material beyond the radiation detector. Measurements must be made using 1 centimeter of water equivalent build up material.
(d)Filters/wedges.
(e)Stray radiation in the useful beam. For equipment manufactured after July 1, 2019, the registrant must 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 comply with International Electrotechnical Commission (IEC) Document 60601-2-1 (or the most current revision or successor national standard).
(f)Beam monitors. All therapeutic radiation machines subject to the requirements of this section must be provided with redundant beam monitoring systems. The sensors for these systems must be fixed in the useful beam during treatment to indicate the dose monitor unit rate.
(v)each beam monitoring system must have a legible display at the treatment control panel. For equipment manufactured after July 1, 2019, each display must: (A) maintain a reading until intentionally reset; (B) have only one scale and no electrical or mechanical scale multiplying factors; (C) utilize a design such that increasing dose is displayed by increasing numbers; and (D) in the event of power failure, the beam monitoring information required by subparagraph (v) of paragraph (3) of this subdivision displayed at the control panel at the time of failure must be retrievable in at least one system for a 20 minute period of time.
(g)Beam symmetry.
(h)Selection and display of dose monitor units.
(j)Termination of irradiation by the beam monitoring system or systems during stationary beam radiation therapy.
(k)Termination of irradiation. It must 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.
(l)Interruption of irradiation. If a therapeutic radiation machine has an interrupt mode, it must be possible to interrupt irradiation and equipment movements at any time from the treatment control panel. Following an interruption, it must be possible to restart irradiation by operator action without any reselection of operating conditions. If any change is made of a pre- selected value during an interruption, irradiation and equipment movements must be automatically terminated.
(m)Timer. A suitable irradiation control device must be provided to terminate the irradiation after a pre-set time interval.
(n)Selection of radiation type. Equipment capable of both x-ray therapy and electron therapy must meet the following additional requirements: (1) irradiation must not be possible until a selection of radiation type (x-rays or electrons) has been made at the treatment control panel; (2) the radiation type selected must be displayed at the treatment control panel before and during irradiation; (3) an interlock system must be provided to: (i) ensure that the equipment can principally emit only the radiation type that has been selected; (ii) prevent irradiation with x-rays, except to obtain an image, when electron applicators are fitted; (iii) prevent irradiation with electrons when accessories specific for x- ray therapy are fitted; and (iv) prevent irradiation if any selected operations carried out in the treatment room do not agree with the selected operations carried out at the treatment control panel.
(o)Selection of energy. Equipment capable of generating radiation beams of different energies must meet the following requirements: (1) irradiation must not be possible until a selection of energy has been made at the treatment control panel; (2) the nominal energy value selected must be displayed at the treatment control panel until reset manually for the next irradiation. After termination of irradiation, it must be necessary to reset the nominal energy value selected before subsequent treatment can be initiated; (3) irradiation must not be possible until the appropriate flattening filter or scattering foil for the selected energy is in its proper location; and (4) for equipment manufactured after July 1, 2019, the selection of energy must comply with International Electrotechnical Commission (IEC) Document 60601-2-1 (or the most current revision or successor national standard).
(p)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 must meet the following requirements: (1) irradiation must not be possible until a selection of stationary beam radiation therapy or moving beam radiation therapy has been made at the treatment control panel; (2) the mode of operation must be displayed at the treatment control panel; (3) an interlock system must be provided to ensure that the equipment can operate only in the mode that has been selected; (4) an interlock system must be provided to prevent irradiation if any selected parameter in the treatment room does not agree with the selected parameter at the treatment control panel; (5) moving beam radiation therapy must be controlled to obtain the selected relationships between incremental dose monitor units and incremental movement. For equipment manufactured after July 1, 2019: (i) an interlock system must be provided to terminate irradiation if the number of dose monitor units delivered in any 10 degrees of rotation or 1 cm of linear 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 delivered must differ by less than 5 percent from the dose monitor unit value selected; (iii) an interlock must be provided to prevent motion of more than 5 degrees or 1 cm beyond the selected limits during moving beam radiation therapy; (iv) an interlock must be provided to require that a selection of direction be made at the treatment control panel in all units which are capable of both clockwise and counter-clockwise moving beam radiation therapy; and (v) moving beam radiation therapy must be controlled with both primary position sensors and secondary position sensors to obtain the selected relationships between incremental dose monitor units and incremental movement.
(6)Where the beam monitor system terminates the irradiation in moving beam radiation therapy, the termination of irradiation must be as required by subdivision (j) of this section.
(7)For equipment manufactured after July 1, 2019, an interlock system must 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 such stoppage is a pre-planned function.
(q)Facility design requirements for therapeutic radiation machines operating above 500 kV. In addition to the shielding requirements of 24 RCNY Health Code § 175.67, the following design elements are required: (1) Protective barriers. All protective barriers must be fixed, except for access doors to the treatment room or movable beam interceptors.
(5)Room entrances. Treatment room entrances must be provided with warning lights in a readily observable position near the outside of all access doors, which will indicate when the useful beam is "ON" and when it is "OFF".
(8)Emergency cutoff switches. At least 1 emergency power cutoff switch must be located in the radiation therapy room and must terminate all equipment electrical power including radiation and mechanical motion. This switch is in addition to the termination switch required by subdivision (k) of this section. All emergency power cutoff switches must include a manual reset so that the therapeutic radiation machine cannot be restarted from the unit's control console without resetting the emergency cutoff switch.
(9)Safety interlocks. All safety interlocks must be designed so that any defect or component failure in the safety interlock system prevents or terminates operation of the therapeutic radiation machine.
(10)Surveys for residual radiation. Surveys for residual activity must be conducted on all therapeutic radiation machines capable of generating photon and electron energies, or proton 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.
(11)Applicants for proton therapy systems capable of operating at 500 keV and above must present documentation of shielding design adequate as determined by the Department to meet the requirements of 24 RCNY Health Code § 175.67. An independent consultant qualified in proton shielding calculation with proven experience in applicable computer simulation, not involved in the original design and with prior approval by the Department must be hired by the applicant to perform an independent verification of the proposed shielding design using site specific equipment and data or information. The independent consultant must prepare a report evaluating the correctness and completeness of the original shielding design calculation, and the adequacy of the shielding design to satisfy the requirements of 24 RCNY Health Code § 175.67. The independent consultant's report must be submitted to the Department by the applicant as an addendum to the application.
(r)QMP support.
(s)Operating procedures.
(t)Acceptance testing, commissioning and full calibration measurements.
(iii)for photon or electron therapy machines, the derivation of all the correction factors applied to the measured beam output data in the calculation of the therapeutic radiation machine's beam output dose rate (as delineated in AAPM Reports TG 21 or TG 51 or any successor publication or national standard) or; (iv) for proton therapy machines, derivation for all the correction factors applied to the measured beam output data in the calculation of the therapeutic radiation machine's beam output dose rate (as delineated in the registrant's calibration protocol). The certified registrant's calibration protocol in the case of proton therapy machines must be submitted to Department for review and approval.
(u)Periodic quality assurance checks.
(w)Quality assurance checks for Intensity-Modulated Radiation Therapy (IMRT) must: (1) include commissioning and testing of the treatment planning and delivery systems, routine quality assurance of the delivery system, and patient-specific validation of treatment plans; and (2) be performed in accordance with "Guidance document on delivery, treatment planning, and clinical implementation of IMRT: Report of the IMRT subcommittee of the AAPM radiation therapy committee: AAPM Report No. 82" (or the most current revision or successor national standard); and (3) be performed in accordance with the manufacturer's specifications. (Added City Record 4/24/2019, eff. 5/24/2019)
