New Hampshire Code of Administrative Rules, Part He-P 4047, Section He-P 4047.07 - Therapeutic Radiation Machines - Photon Therapy Systems (500 kV and Above) and Electron Therapy Systems (500 keV and Above) | New Hampshire Code of Administrative Rules

(a) Each facility location authorized to use a therapeutic radiation machine in accordance with He-P 4047.07 shall possess, operable and calibrated in accordance with He-P 4047.08, portable monitoring equipment to include as a minimum a portable radiation measurement survey instrument capable of measuring dose rates over the range 10 µSv (1 mrem) per hour to 10 mSv (1000 mrem) per hour.

(b) Leakage radiation outside the maximum useful beam in photon and electron modes shall meet the following requirements:

(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 or patient plane, shall 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 when measurements are averaged over an area not exceeding 100 square centimeters at a minimum of 16 points uniformly distributed in the plane;

(2) Except for the area defined in He-P 4047.07(b) (1) , 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 shall not exceed 0.5 percent of the absorbed dose on the central axis of the beam at the nominal treatment distance when measurements are averaged over an area not exceeding 100 square centimeters;

(3) The neutron absorbed dose outside the useful beam shall be in compliance with International Electrotechnical Commission (IEC) Document 60601-2-1, as amended, which is incorporated by reference and included in Appendix A;

(4) 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 4047.07(b) (1) -(3) for the specified operating conditions; and

(5) Records on leakage radiation measurements shall be maintained after installation for inspection by DHHS/RHS.

(c) Leakage radiation through beam limiting devices shall be as follows:

(1) For photon radiation, all adjustable or interchangeable beam limiting devices shall attenuate the useful beam such that at the nominal treatment distance, the maximum absorbed dose anywhere in the area shielded by the beam limiting device(s) shall not exceed 5 percent of the maximum absorbed dose on the central axis of the useful beam measured in a 100 square centimeter radiation field or maximum available field size if less than 100 square centimeters;

(2) For electron radiation, all 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, such that the absorbed dose in a plane perpendicular to the central axis of the useful beam at the nominal treatment distance shall not exceed:

a. For points beyond a line 7 centimeters outside the periphery of the useful beam, a maximum limit 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; and

b. For points beyond a line 2 centimeters up to 7 centimeters outside the periphery of the useful beam, a maximum limit of 10 percent of the absorbed dose on the central axis of the useful beam at the nominal treatment distance;

(3) Measurements of leakage radiation through the beam limiting for photon radiation devices shall be:

a. Made with the beam limiting devices closed;

b. Made with any residual aperture blocked by at least 2 tenth value layers of suitable absorbing material;

c. Measured independently at the depth of maximum dose for each set of overlapping beam limiting device; and

d. The depth of maximum dose made using a radiation detector of area not exceeding 10 square centimeters;

(4) Measurements of leakage radiation through the electron applicators shall:

a. Be made with the electron beam directed into the air;

b. Use 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; and

c. Be made using one centimeter of water equivalent build up material; and

(5) Leakage radiation through beam limiting devices shall be determined for photon radiation and for electron radiation in radiation therapy machines which operate in both modes.

(d) Filters and wedges used in therapeutic radiation machines shall meet the following requirements:

(1) Each wedge filter which is removable from the system shall be clearly marked with an identification number;

(2) Each removable wedge filter shall have the nominal wedge angle appear on the wedge or wedge tray if permanently mounted to the tray;

(3) If the wedge or wedge tray is significantly damaged, the wedge transmission factor shall be redetermined;

(4) If the absorbed dose rate information required by He-P 4047.07(i) relates exclusively to operation with a field flattening filter or beam scattering foil in place, such foil or filter shall be removable only by the use of tools; and

(5) For equipment which utilizes a system of wedge filters, interchangeable field flattening filters, or interchangeable beam scattering foils:

a. Irradiation shall not be possible until a selection of a filter or a positive selection to use "no filter" has been made at the treatment control panel, either manually or automatically;

b. An interlock system shall be provided to prevent irradiation if the filter selected is not in the correct position;

c. A display shall be provided at the treatment control panel showing the wedge filter(s), interchangeable field flattening filter(s), and/or interchangeable beam scattering foil(s) in use; and

d. An interlock shall be provided to prevent irradiation if any filter and/or beam scattering foil selection operation carried out in the treatment room does not agree with the filter and/or beam scattering foil selection operation carried out at the treatment control panel.

(e) 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 are in compliance with International Electrotechnical Commission (IEC) Document 60601-2-1 which is incorporated by reference and included in Appendix A.

(f) All therapeutic radiation machines subject to He-P 4047.07 shall meet the following requirements:

(1) All therapeutic radiation machines shall be provided with:

a. Redundant beam monitoring systems which have sensors fixed in the useful beam during treatment to indicate the dose monitor unit rate;

b. At least 2 independently powered integrating dose meters if manufactured after July 1, 1998; and

c. At least one radiation detector incorporated into a useful beam monitoring system, if manufactured before July 1, 1998; and

(2) The detector and the system into which that detector is incorporated shall meet the following requirements:

a. Each detector shall be removable only with tools;

b. If the detector is movable, it shall be interlocked to prevent incorrect positioning;

c. Each detector 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;

d. Each beam monitoring system shall be capable of independently monitoring, interrupting, and terminating irradiation;

e. The design of the beam monitoring systems shall ensure that the:

1. Malfunctioning of one system shall not affect the correct functioning of the other system(s); and

2. Failure of either system shall terminate irradiation or prevent the initiation of radiation; and

f. Each beam monitoring system shall have a legible display at the treatment control panel which shall:

1. Maintain a reading until intentionally reset;

2. Have only one scale and no electrical or mechanical scale multiplying factors;

3. Utilize a design such that increasing dose is displayed by increasing numbers; and

4. In the event of power failure, the beam monitoring information 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.

(g) Bent-beam linear accelerators shall be provided with auxiliary device(s) to monitor beam symmetry which:

(1) Shall be able to detect field asymmetry greater than 10 percent; and

(2) Shall be configured to terminate irradiation if the specifications above cannot be maintained.

(h) Selection and display of dose monitor units shall be as follows:

(1) Irradiation shall not be possible until a new selection of a number of dose monitor units has been made at the treatment control panel;

(2) The pre-selected number of dose monitor units shall be displayed at the treatment control panel until reset manually for the next irradiation;

(3) After termination of irradiation, it shall be necessary to reset the dosimeter display before subsequent treatment can be initiated; and

(4) After termination of irradiation, it shall be necessary for the operator to reset the pre-selected dose monitor units before irradiation can be initiated.

(i) A system shall be provided from whose readings the air kerma rate or absorbed dose rate a reference point can be calculated, and which meets the following requirements:

(1) The dose monitor unit rate shall be displayed at the treatment control panel;

(2) If the equipment can deliver under any conditions 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;

(3) The dose rate at which the irradiation will be terminated shall be a record maintained by the registrant;

(4) If the equipment can deliver under any fault condition(s) an air kerma rate or absorbed dose rate at the nominal treatment distance more than 10 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);

(5) For each therapeutic radiation machine, the registrant shall determine, or obtain from the manufacturer, the maximum value(s) for the specified operating conditions; and

(6) Records of maximum value(s) shall be maintained at the installation for inspection by DHHS/RHS.

(j) Termination of irradiation by the beam monitoring system or systems during stationary beam radiation therapy shall be as follows:

(1) Each primary system shall terminate irradiation when the pre-selected number of dose monitor units has been detected by the system;

(2) If the original design of the equipment includes 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 pre-selected number of dose monitor units, set at the control panel, has been detected by the secondary dose monitoring system; and

(3) An indicator on the control panel shall show which monitoring system has terminated radiation.

(k) 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.

(l) If a therapeutic radiation machine has an interrupt mode:

(1) It shall be possible to interrupt irradiation and equipment movements at any time from the treatment control panel;

(2) Following an interruption it shall be possible to restart irradiation by operator action without any re-selection of operating conditions; and

(3) If any change is made of a pre-selected value during an interruption, irradiation and equipment movements shall be automatically terminated.

(m) A suitable irradiation control device shall be provided to terminate the irradiation after a pre-set time interval as follows:

(1) A timer shall be provided which has a display at the treatment control panel;

(2) The time provided shall have a pre-set time selector and an elapsed time indicator;

(3) 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;

(4) After irradiation is terminated and before irradiation can be re-initiated, it shall be necessary to reset the elapsed time indicator; and

(5) The timer shall terminate irradiation when a pre-selected time has elapsed, if the dose monitoring systems have not previously terminated irradiation.

(n) Equipment capable of both x-ray therapy and electron therapy shall meet the following additional requirements:

(1) Irradiation shall 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 shall be displayed at the treatment control panel before and during irradiation;

(3) An interlock system shall be provided to ensure that the equipment can principally emit only the radiation type which has been selected;

(4) An interlock system shall be provided to prevent irradiation with x-rays, except to obtain an image, when electron applicators are fitted;

(5) An interlock system shall be provided to prevent irradiation with electrons when accessories specific for x-ray therapy are fitted; and

(6) An interlock system shall be provided to 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) Equipment capable of generating radiation beams of different energies shall meet the following requirements:

(1) Irradiation shall not be possible until a selection of energy has been made at the treatment control panel;

(2) The nominal energy value selected shall be displayed at the treatment control panel until reset manually for the next irradiation;

(3) After termination of irradiation, it shall be necessary to reset the nominal energy value selected before subsequent treatment can be initiated;

(4) Irradiation shall not be possible until the appropriate flattening filter or scattering foil for the selected energy is in its proper location; and

(5) The selection of energy shall be in compliance with International Electrotechnical Commission (IEC) Document 60601-2-1, which is incorporated by reference and included in Appendix A.

(p) Therapeutic radiation machines capable of both stationary beam radiation therapy and moving beam radiation therapy shall meet the following requirements:

(1) 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;

(2) The mode of operation shall be displayed at the treatment control panel;

(3) An interlock system shall be provided to ensure that the equipment can operate only in the mode which has been selected;

(4) An interlock system shall 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 irradiation therapy shall be controlled to obtain the selected relationships between incremental dose monitor units and incremental movement as follows:

a. An interlock system shall be provided to terminate irradiation if the number of dose monitor units delivered in any 10 degrees of rotation or one cm of linear motion differs by more than 20 percent from the selected value;

b. Where angle terminates the irradiation in moving beam radiation therapy, the dose monitor units delivered shall differ by less than 5 percent from the dose monitor unit value selected;

c. An interlock shall be provided to prevent motion of more than 5 degrees or 1 cm beyond the selected limits during moving beam radiation therapy;

d. An interlock shall 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

e. 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;

(6) Where the beam monitor system terminates the irradiation in moving beam radiation therapy, the termination of irradiation shall be as required by He-P 4047.07(j) ; and

(7) An interlock system shall be provided to terminate irradiation if movement:

a. Occurs during stationary beam radiation therapy; or

b. Does not start or stops during moving beam radiation therapy unless stoppage is a pre-planned function.

(q) In addition to shielding adequate to meet requirements of He-P 4047.09, the following design requirements are made for therapeutic radiation machines operating above 500 kV:

(1) All protective barriers shall be fixed, except for access doors to the treatment room or movable beam interceptors;

(2) The control panel shall:

a. Be located outside the treatment room;

b. Provide an indication of whether electrical power is available at the control panel and if activation of the radiation is possible;

c. Provide an indication or whether radiation is being produced; and

d. Include an access control (locking) device which will prevent unauthorized use of the therapeutic radiation machine;

(3) 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;

(4) The therapeutic radiation machine shall not be used for patient irradiation unless at least one viewing system is operational;

(5) Provision shall be made for continuous two-way aural communication between the patient and the operator at the control panel;

(6) The therapeutic radiation machine shall not be used for irradiation of patients unless continuous two-way aural communication is possible;

(7) Treatment room entrances shall 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) Interlocks shall be provided such that all access controls are activated before treatment can be initiated or continued;

(9) If the radiation beam is interrupted by any access control, it shall not be possible to restore the machine to operation without resetting the access control and re-initiating irradiation by manual action at the control panel;

(10) If the shielding material in any protective barrier requires the presence of a beam interceptor to ensure compliance with He-P4020.13, 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 barrier(s);

(11) At least one emergency power cutoff switch in addition to the termination switch shall be located in the radiation therapy room and shall terminate all equipment electrical power including radiation and mechanical motion;

(12) All emergency power cutoff switches shall 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;

(13) All safety interlocks shall be designed so that any defect or component failure in the safety interlock system prevents or terminates operation of the therapeutic radiation machine; and

(14) Surveys for residual activity shall be conducted on all 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.

(r) The services of the radiation therapy physicist shall be required in facilities having therapeutic radiation machines with energies of 500 kV and above.

(s) The radiation therapy physicist required in He-P 4047.07(r) shall be responsible for:

(1) Full calibration(s) required by He-P 4047.07(u) ;

(2) Protection surveys required by He-P 4047.05;

(3) Supervision and review of dosimetry;

(4) Beam data acquisition and transfer for computerized dosimetry and supervision of its use;

(5) Quality assurance, including quality assurance check review required by He-P 4047.07(v) (6) ;

(6) Consultation with the authorized user in treatment planning, as needed; and

(7) Performing calculation and assessments regarding misadministrations.

(t) The following operating procedures shall be required:

(1) If the radiation therapy physicist is not a full-time employee of the registrant, the operating procedures shall specifically address how the radiation therapy physicist is to be contacted for problems or emergencies, as well as the specific actions, if any, to be taken until the radiation therapy physicist can be contacted;

(2) No individual, other than the patient, shall be in the treatment room during treatment or during any irradiation for testing or calibration purposes;

(3) Therapeutic radiation machines shall not be made available for medical use unless the requirements of He-P 4047.05 and He-P 4047.07(u) and (v) have been met;

(4) Therapeutic radiation machines, when not in operation, shall be secured to prevent unauthorized use;

(5) When adjustable beam limiting devices are used, the position and shape of the radiation field shall be indicated by a light field;

(6) If a patient must be held in position during treatment, mechanical supporting or restraining devices shall be used; and

(7) A copy of the current operating and emergency procedures shall be maintained at the therapeutic radiation machine control console.

(u) Acceptance testing, commissioning, and full calibration measurements shall be as follows:

(1) Acceptance testing, commissioning, and full calibration of a therapeutic radiation machine shall be performed by, or under the direct supervision of, a radiation therapy physicist;

(2) Acceptance testing and commissioning shall be performed in accordance with "AAPM Code of Practice for Radiotherapy Accelerators" (1994) prepared by AAPM Radiation Therapy Task Group 45, which is incorporated by reference and included in Appendix A, and the manufacturer's contractual specifications;

(3) Acceptance testing and commissioning shall be conducted before the first medical use following installation or reinstallation of the therapeutic radiation machine;

(4) Full calibration shall include measurement of all parameters required by Table II of "Comprehensive QA for Radiation Oncology" (1994) prepared by AAPM Radiation Therapy Committee Task Group 40, which Report and Table are incorporated by reference and included in Appendix A;

(5) Full calibration shall be performed in accordance with "AAPM Code of Practice for Radiotherapy Accelerators" (1994) prepared by AAPM Radiation Therapy Task Group 45 which is incorporated by reference and included in Appendix A;

(6) It shall not be necessary to complete all elements of a full calibration at the same time, all applicable parameters (for all energies) shall be completed at intervals not exceeding 12 calendar months, unless a more frequent interval is required in Table II of "Comprehensive QA for Radiation Oncology" (1994) prepared by AAPM Radiation Therapy Committee Task Group 40, which is incorporated by reference and included in Appendix A;

(7) The radiation therapy physicist shall perform all elements of a full calibration necessary to determine that all parameters are within acceptable limits as follows:

a. 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 difference cannot be reconciled;

b. Therapeutic radiation machines with multi-energy and/or multi-mode capabilities shall only require measurements for those modes and/or energies that are not within their acceptable range;

c. Following any component replacement, major repair, or modification of components that could significantly affect the characteristics of the radiation beam;

d. If the repair, replacement, or modification does not affect all modes and/or energies, measurements shall be performed on the effected mode/energy that is in most frequent clinical use at the facility; and

e. The remaining energies/modes may be validated with quality assurance check procedures against the criteria in He-P 4047.07(u) (7) ;

(8) The registrant shall use the dosimetry system described in He-P 4047.05(h) and (i) to measure the radiation output for one set of exposure conditions;

(9) The remaining radiation measurements required in He-P 4047.07(u) (2) -(6) may be made using a dosimetry system that indicates relative dose rates;

(10) The registrant shall maintain a record of each calibration in an auditable form for the life of the therapeutic radiation machine; and

(11) The record required in He-P 4047.07(u) (10) shall include:

a. The date of the calibration;

b. The manufacturer's name;

c. Model number of the therapeutic machine;

d. Serial number of the therapeutic machine;

e. The model numbers and serial numbers of the instruments used to calibrate the therapeutic radiation machine; and

f. The signature of the radiation therapy physicist responsible for performing the calibration.

(v) Periodic quality assurance checks shall meet the following requirements:

(1) Periodic quality assurance checks shall be performed on all therapeutic radiation machines subject to He-P 4047.07 at intervals not to exceed those specified in "Comprehensive QA for Radiation Oncology" (1994), prepared by AAPM Radiation Therapy Committee Task Group 40, which is incorporated by reference and included in Appendix A;

(2) Quality assurance checks shall include determination of central axis radiation output and a representative sampling of periodic quality assurance checks contained in "Comprehensive QA for Radiation Oncology" (1994) prepared by AAPM Radiation Therapy Committee Task Group 40 which is incorporated by reference and included in Appendix A;

(3) Representative sampling as required in He-P 4047.07(v) (2) shall include all referenced periodic quality assurance checks in an interval not to exceed 12 consecutive calendar months;

(4) The registrant shall use a dosimetry system which has been intercompared within the previous 12 months with the dosimetry system described in He-P 4047.05(h) and (i) to make the periodic quality assurance checks;

(5) The registrant shall perform periodic quality assurance checks in accordance with procedures established by the radiation therapy physicist;

(6) The registrant shall review the results of each periodic radiation output check according to the following procedures:

a. The authorized user and radiation therapy physicist shall be immediately notified if any parameter is not within its acceptable tolerance;

b. 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 tolerances;

c. If all quality assurance check parameters appear to be within their acceptable range, the quality assurance check shall be reviewed and signed by either the authorized user or radiation therapy physicist within 3 treatment days; and

d. The radiation therapy physicist shall review and sign the results of each radiation output quality assurance check at intervals not exceed 30 days;

(7) Therapeutic radiation machines subject to He-P 4047.07 shall have safety quality assurance checks listed in "Comprehensive QA for Radiation Oncology" (1994) prepared by AAPM Radiation Therapy Committee Task Group 40, which is incorporated by reference and included in Appendix A, performed at intervals not to exceed 7 days;

(8) To satisfy the requirement of He-P 4047.07(v) (7) , safety quality assurance checks shall ensure proper operation of:

a. Electrical interlocks at each external beam radiation therapy room entrance;

b. The "BEAM-ON", interrupt, and termination switches;

c. Beam condition indicator lights on the access doors, control console, and in the radiation therapy room;

d. Viewing systems;

e. Electrically operated treatment room door(s) from inside and outside the treatment room; and

f. At least one emergency power cutoff switch, as follows:

1. If more than one emergency power cutoff switch is installed and not all switches are tested at once, each switch shall be tested on a rotating basis; and

2. 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.

(9) The registrant shall promptly repair any system identified in He-P 4047.07(v) (8) that is not operating properly;

(10) The registrant shall maintain a record of each quality assurance check required for 3 years; and

(11) The record required in He-P 4047.07(v) (10) shall include:

a. The date of the quality assurance check;

b. The manufacturer's name;

c. The machine model number;

d. The machine serial number;

e. The manufacturer's name, model number, and serial number of the instrument(s) used to measure the radiation output of the therapeutic radiation machine; and

f. The signature of the individual who performed the periodic quality assurance check.

(w) For intensity modulated radiation therapy (IMRT), quality assurance checks shall:

(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 plan;

(2) Be performed in accordance with "Guidance document on delivery, treatment planning, and clinical implementation of IMRT" (2003) Report of the IMRT subcommittee of the AAPM radiation therapy committee: AAPM Report No. 82, which is incorporated by reference and included in Appendix A;

(3) Be performed in accordance with the manufacturer's contractual specifications.