410 IAC 5-6.1-125 Therapeutic x-ray or electron systems operating at one MeV or more

Sec. 125. (a) This section and 410 IAC 5-9, excluding 410 IAC 5-9-8(a), 410 IAC 5-9-10(a), 410 IAC 5-9-10(c), and 410 IAC 5-9-10(d), shall apply to medical facilities using therapeutic x-ray or electron systems capable of operating at one (1) MeV or more. (b) Therapeutic x-ray or electron systems manufactured after January 1, 1985, shall comply with the following: (1) The absorbed dose due to leakage radiation, when measured at any point in the patient plane, shall not exceed one-tenth of one percent (0.1%) for x-ray leakage or five-hundredths percent (0.05%) for neutron leakage of the maximum absorbed dose of the unattenuated useful beam measured at the point of intersection of the central axis of the beam and the isocenter or normal treatment distance. (2) For each therapeutic x-ray or electron system, the registrant shall determine or obtain from the manufacturer the leakage radiation existing at the positions specified in subdivision (1) for operating conditions producing maximum leakage radiation. Radiation measurements excluding neutrons shall be averaged over an area of one hundred (100) square cm or less. Neutron measurements shall be averaged over an area of two hundred (200) square cm or less. Records on leakage radiation measurements shall be maintained for inspection by the commissioner. (c) Therapeutic x-ray or electron systems manufactured on or before January 1, 1985, shall comply with the following: (1) The absorbed dose due to leakage radiation at any point in the patient plane shall not exceed one-tenth of one percent (0.1%) of the maximum absorbed dose of the unattenuated useful beam measured at the point of intersection of the central axis of the beam and the isocenter or normal treatment distance for x-ray leakage. (2) For each system, the registrant shall determine or obtain from the manufacturer the leakage radiation existing at the positions specified in subdivision (1) for operating conditions producing maximum leakage radiation. Radiation measurements shall be averaged over an area of one hundred (100) square cm or less. Records on leakage radiation measurements shall be maintained for inspection by the commissioner. (d) Adjustable or interchangeable beam-limiting devices shall be provided. Such devices shall transmit no more than two percent (2%) of the useful beam, excluding its neutron component, at the normal treatment distance for the portion of the useful beam which is to be attenuated by the beam-limiting device. (e) Each filter which is removable from the system shall be clearly marked with an identification number. Documentation shall be available at the control panel describing each filter. For wedge filters, the wedge angle shall be indicated on the wedge or wedge tray. If the absorbed dose rate data required by subsection (t) relates exclusively to operation with a field-flattening or beam-scattering filter in place, such filter shall not be removable by hand. (f) Those therapeutic x-ray or electron systems manufactured after January 1, 1985, which utilize a system of wedge filters, interchangeable field-flattening filters, or interchangeable beam-scattering filters shall comply with the following: (1) Irradiation shall not be possible until a selection of a filter or filter code has been made at the x-ray control panel. (2) An interlock system shall be provided to prevent irradiation if the filter selected is not in the correct position. (3) An interlock shall be provided to prevent irradiation if any filter selection operation carried out in the treatment room does not agree with the filter selection operation carried out at the x-ray control panel. (g) The registrant shall determine, or obtain from the manufacturer, data sufficient to assure that the following requirements are met: (1) The absorbed dose resulting from x-rays in a useful electron beam at a point on the central axis of the beam ten (10) cm greater than the practical range of the electrons shall not exceed the values stated in the table in this subdivision. Linear interpolation shall be used for values not stated. TABLE III X-Ray Absorbed Dose Maximum Energy as a Fraction of of Electron Beam Maximum Dose 1 MeV 0.03 15 MeV 0.05 35 MeV 0.10 50 MeV 0.20 Compliance shall be determined using the following: (A) A measurement within a phantom with the incident surface of the phantom at the normal treatment distance and normal to the central axis of the beam. (B) A phantom having cross sectional dimensions which exceed the measurement radiation field by at least five (5) cm and of depth sufficient to perform the required measurement. (2) The absorbed dose at a surface located at the normal treatment distance, at the point of intersection of that surface with the central axis of the useful beam during x-ray irradiation, shall not exceed the limits stated in the table in this subdivision. Linear interpolation shall be used for values not stated. TABLE IV Absorbed Dose at the Surface as a Fraction Maximum Photon Energy of the Maximum Dose 1 MeV 0.80 2 MeV 0.70 5 MeV 0.60 15 MeV 0.50 35 MeV 0.40 50 MeV 0.20 Compliance shall be determined by measurements made as follows: (A) Within a phantom using an instrument which will allow extrapolation to the surface absorbed dose. (B) Using a phantom having size and placement which complies with subdivision (1). (C) After removal of all beam-modifying devices which can be removed by hand, except for beam-scattering or beam-flattening filters. (h) All therapeutic x-ray or electron systems shall be provided with one (1) or more dose monitoring chambers, in accordance with the following: (1) Therapeutic x-ray or electron systems manufactured after January 1, 1985, shall be provided with at least two (2) dose monitoring chambers. The dose monitoring chambers shall be incorporated into two (2) separate dose monitoring systems. (2) Therapeutic x-ray or electron systems manufactured on or before January 1, 1985, shall be provided with at least one (1) dose monitoring chamber. The dose monitoring chamber shall be incorporated into the primary dose monitoring system. (i) Each dose monitoring chamber shall be removable only by use of tools and shall be interlocked to prevent incorrect positioning. Each dose monitoring chamber shall form part of a dose monitoring system from which readings of the absorbed dose at a reference point in the treatment volume can be calculated in dose monitor units. Each dose monitoring system shall be capable of independently monitoring, interrupting, and terminating irradiation. Each dose monitoring system shall have a legible display located at the control panel. (j) Therapeutic x-ray or electron systems manufactured after January 1, 1985, shall comply with this subsection. The design of each dose monitoring system shall assure that malfunctioning of one (1) system shall not cause incorrect functioning of the second system. The failure of any element common to both monitoring systems which could affect the correct function of both systems shall terminate irradiation. Each dose monitoring system display shall: (1) maintain a reading until intentionally reset to the zero (0) position; (2) have only one (1) scale and no scale multiplying factors; (3) utilize a design such that increasing dose is displayed by increasing numbers; and (4) be such that, in the event a dose monitoring system fails, the dose monitor units delivered may be accurately determined. In the event of a power failure, the dose monitoring information displayed at the control panel at the time of the power failure shall be retrievable from at least one (1) dose monitoring system. (k) For therapeutic x-ray or electron systems manufactured after January 1, 1985, which are inherently capable of producing useful beams with asymmetry exceeding five percent (5%), the asymmetry of the radiation beam in two (2) orthogonal directions shall be monitored before the beam passes through the beam-limiting device. Monitoring devices, indicators, and controls shall be provided so that if the difference in dose rate between one (1) region and another region symmetrically displaced from the central axis of the beam exceeds five percent (5%) of the central axis dose rate, this condition is indicated at the control panel. If the difference exceeds ten percent (10%), the controls shall automatically terminate irradiation. (l) Irradiation shall not be possible until selection of the number of dose monitor units to be delivered has been made at the control panel. The preselected number of dose monitor units shall be displayed at the control panel until reset manually for the next irradiation. After termination of irradiation, it shall be necessary to reset the dosimeter display to the zero (0) position before subsequent treatment can be initiated. (m) During stationary beam therapy, the primary dose monitoring system shall terminate irradiation when the preselected number of dose monitor units have been detected by that system. If original design of the equipment included a second dose monitoring system, that system shall be capable of terminating irradiation when the system detects that the preselected number of dose monitoring units set at the control panel indicate either fifteen percent (15%), or greater, or forty (40) dose monitor units, or greater, above the preselected number of dose monitor units set at the control panel. For therapeutic x-ray or electron systems manufactured after January 1, 1985, which are used for stationary beam therapy: (1) a second dose monitoring system shall be incorporated which can terminate irradiation when fifteen percent (15%), or greater, or forty (40) dose monitor units, or greater, above the number selected at the x-ray control panel has been detected by the second dose monitoring system; and (2) the control panel shall indicate which dose monitoring system has terminated irradiation. (n) It shall be possible to interrupt irradiation and gantry rotation at any time at the control panel. Following an interruption, it shall be possible for the operator to commence irradiation without reselecting operating conditions. If any change is made of a preselected value during an interruption, irradiation and gantry rotation shall be automatically terminated. (o) A timer that has a display shall be provided at the control panel. The timer shall have a preset time selector and an elapsed time indicator. The timer shall be a cumulative timer that activates with the production of radiation and retains its reading after irradiation is interrupted or terminated. After irradiation is terminated, it shall be necessary to reset the elapsed time indicator to the zero (0) position before irradiation can be initiated. The timer shall terminate irradiation when a preselected time has elapsed if the dose monitoring systems have not previously terminated irradiation. (p) Equipment capable of both x-ray therapy and electron therapy shall comply with the following additional requirements: (1) Irradiation shall not be possible until the type of radiation to be utilized has been selected at the control panel. The type of radiation selected shall be displayed at the control panel before and during irradiation. (2) An interlock system shall be provided to ensure that the equipment can emit only that type of radiation which has been selected. (3) An interlock system shall be provided to prevent irradiation if operating conditions selected in the treatment room do not agree with the operating conditions selected at the control panel. (4) When electron applicators are fitted, an interlock system shall prevent irradiation with x-rays except to obtain a port film. (5) An interlock system shall be provided to prevent irradiation with electrons when accessories specific for x-ray therapy are fitted. (q) Equipment capable of generating radiation beams of different energies shall comply with the following: (1) Irradiation shall not be possible until an energy value has been selected at the control panel. The energy value selected shall be displayed at the control panel before and during irradiation. (2) An interlock system shall be provided to prevent irradiation if operating conditions selected in the treatment room do not agree with the operating conditions selected at the control panel. (3) For therapy systems manufactured after January 1, 1985, except systems that employ a straight through waveguide design, an interlock system shall be provided to terminate irradiation if the bending magnet current for the energy selected varies by more than ten percent (10%) of its normal value. (r) Equipment capable of both stationary beam therapy and moving beam therapy shall comply with the following: (1) Irradiation shall not be possible until either stationary beam therapy or moving beam therapy has been selected at the control panel. The mode of treatment selected shall be displayed at the x-ray control panel. (2) An interlock system shall be provided to ensure that the equipment can operate only in the mode selected. (3) An interlock system shall be provided to prevent irradiation if any operation selected to be carried out in the treatment room does not agree with the operation selected at the control panel. (4) For therapy systems manufactured after January 1, 1985, an interlock system shall be provided to terminate irradiation if the gantry moves during stationary beam therapy, or if the gantry ceases rotation before the preselected arc is swept, unless the stoppage is preplanned. (5) Moving beam therapy shall be controlled to obtain the selected relationships between incremental dose monitor units and incremental angle of movement. (6) Therapy systems manufactured after January 1, 1985, shall also comply with the following: (A) An interlock system shall be provided to terminate irradiation if the gantry speed, dose rate, or dose rate per degree varies by more than twenty percent (20%) of the preselected value. (B) For moving beam therapy wherein irradiation is terminated based on the arc swept, the dose monitor units shall differ by less than five percent (5%) from the value calculated for the absorbed dose per unit angle. (C) For moving beam therapy wherein the dose monitor system terminates irradiation, the termination shall be in accordance with subsection (m). (s) For therapy systems manufactured after January 1, 1985, a system shall be provided from which readings of the absorbed dose rate at a reference point in the treatment volume can be calculated. The dose monitoring chambers specified in subsection (h) may form part of this system. The dose monitor unit rate shall be displayed at the control panel. (t) The registrant shall determine, or shall obtain from the manufacturer, the location of the target or the virtual source of x-rays with reference to an accessible point on the radiation head. If the equipment is capable of electron therapy, the registrant shall also determine, or shall obtain from the manufacturer, the location of the electron window with reference to an accessible point on the radiation head. (u) Capability shall be provided for radiation safety interlocks to be checked for proper operation. (v) Facilities which will house therapeutic x-ray or electron systems capable of operating at more than one (1) MeV shall comply with 410 IAC 5-4 and the following: (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. (3) Windows, mirrors, closed circuit television, or an equivalent system shall be provided to permit continuous observation of the patient during irradiation and shall be located so the operator can observe the patient from the control panel. (4) When the primary viewing system is electronic, either an alternate viewing system shall be available for use in the event of failure of the primary viewing system, or the therapeutic x-ray or electron system shall not be used when the primary viewing system is not fully functional. Alternate viewing systems may also be electronic. In the event of failure of both viewing systems, the therapeutic x-ray or electron system shall not be used to irradiate patients until one (1) of the viewing systems is again fully operational. (5) Provision shall be made for verbal communication between the patient and the operator at the control panel. However, where treatment requirements or excessive noise levels make verbal communication impractical, other effective methods of communication shall be utilized. (6) Each treatment room entrance shall be provided with a readily observable warning light near the outside of the entrance. The warning light shall indicate when irradiation is in progress in the treatment room. (7) Interlocks shall be provided such that all treatment room entrances must be closed before treatment can be initiated or continued. If the radiation beam is interrupted by any door opening, it shall not be possible to continue irradiation without closing all entrance doors and manually reinitiating irradiation at the control panel. (w) Registrants shall have all new therapeutic x-ray or electron facilities, and existing facilities not previously surveyed, surveyed by a radiation oncology physicist approved by the department. Such surveys shall also be performed after any change in the facility or equipment which might cause a significant increase in radiation hazard. The registrant shall obtain a written report of the survey from the radiation oncology physicist, and a copy of the report shall be transmitted by the registrant to the commissioner within thirty (30) days of receipt of the report of the survey. The survey and report shall indicate all locations where the dose equivalent rate exceeds the limits specified in this rule. (x) The registrant shall establish procedures to check all monitor unit calculations by an independent method or by a second individual before administering thirty percent (30%) of the prescribed total dose to assure that the dose to a single point on the central axis, or to a point of special interest, agrees with the manual or computer generated dose calculation and with the written order of a practitioner of the healing arts. Additionally, the registrant shall verify that the correct central axis depth-dose values, field size factors, off-axis ratios, and beam modifying factors are used and documented. (y) Calibration of therapeutic x-ray or electron systems subject to this section shall be performed in accordance with an established calibration protocol acceptable to the commissioner, such as the protocol established by the American Association of Physicists in Medicine. The calibrations shall be performed before the system is first used for irradiation of an individual, and thereafter at time intervals not to exceed twelve (12) months. Calibrations shall also be performed after any change which might significantly alter the dose monitor unit, beam energy, spatial distribution, or other characteristics of the therapy beam. Calibration shall be performed by a radiation oncology physicist approved by the department, who is physically present at the facility. Radiation measurements conducted during calibrations required by this subsection shall be performed using a dosimetry system which complies with the following: (1) The dosimetry system shall have an air-kerma calibration factor for cobalt 60 gamma rays traceable to the National Institute for Standards and Technology. (2) The dosimetry system shall have been calibrated within the previous two (2) years and after any servicing that may have affected its calibration. The system shall have been calibrated in such a fashion that an uncertainty can be stated for the radiation output measured by the system. The dosimetry system shall have had constancy checks performed on the system as specified by a radiation oncology physicist approved by the department. Calibration shall be in sufficient detail that the dose at a reference point in soft tissue may be calculated with a maximum uncertainty of five percent (5%). (3) Calibration of each therapy beam shall include, but not be limited to, the following determinations: (A) Verification that the equipment is operating in compliance with the design specifications concerning the radiographic isocenter, light-radiation field congruency, laser alignment, optical distance indicator, field size indicators, variation in the axis of rotation for the table, collimator, gantry, and beam flatness and symmetry at specified depths for various gantry angles. (B) Verification of beam energy, output factors, off-axis ratios, dose-depth values, and isodose data for each beam. (C) Verification of transmission data for all beam modification devices such as wedges, blocking trays, compensators, and custom blocks. (D) Verification that existing depth-dose data and isodose charts applicable to the equipment continues to be valid or are updated to existing machine conditions. Records of calibration measurements and dosimetry system calibrations conducted in accordance with this subsection shall be maintained by the registrant for at least five (5) years after completion of such calibration. (z) An independent check of the output of each therapeutic beam shall be performed annually. The check shall be performed by either of the following: (1) A radiation oncology physicist approved by the department, other than the one who performed the annual output calibration, using a dosimetry system other than the one that was used during the annual calibration. The dosimetry system must also comply with subsection (y). (2) A thermoluminescence dosimetry service capable of measuring doses with an accuracy of five percent (5%) or less. (aa) Output spot checks shall be performed on therapeutic x-ray or electron systems during spot checks conducted in accordance with subsection (y), and thereafter at intervals not to exceed one (1) month by a radiation oncology physicist approved by the department. Output spot check procedures shall be in writing and shall have been developed by a radiation oncology physicist approved by the department. Output spot check procedures shall specify which tests or measurements to be performed, the frequency the tests or measurements are to be performed, the acceptable tolerance for each parameter measured compared to the value for that parameter as determined in the last calibration conducted in accordance with subsection (y), and the action to be taken if a tolerance has been exceeded for any test or measurement required by the written output spot check procedures. Written output spot check procedures are required for at least the following parameters: (1) Output per monitor unit. (2) Light-radiation field congruency. (3) Laser alignment. (4) Optical distance indicators. (5) Field size indicators. If an output spot check conducted in accordance with this subsection indicates a variance of more than five percent (5%) in output per monitor unit compared to the value determined in the last spot check conducted in this subsection, the radiation oncology physicist shall calibrate the therapeutic x-ray system. Records of each output calibration measurement conducted in accordance with this subsection shall be maintained by the registrant for a minimum of five (5) years from the date the output calibration was performed. (bb) The registrant shall perform weekly output constancy checks on each of their therapeutic x-ray or electron systems in accordance with written output constancy check procedures developed by a radiation oncology physicist approved by the department. The output constancy check procedures shall specify the following: (1) The tests or measurements to be performed. (2) The acceptable tolerance for each parameter measured compared to the value for that parameter as determined in the last calibration conducted in accordance with subsection (y). (3) The action to be taken if a tolerance has been exceeded for a test or measurement required by the written output constancy check procedures. At least monthly, a radiation oncology physicist approved by the department shall review the results of all required output constancy checks performed since his or her last such review. If an output constancy check conducted in accordance with this subsection indicates a variance of more than five percent (5%) in output per monitor unit compared to the value determined in the last calibration conducted in accordance with subsection (y), the registrant shall repair the therapeutic x-ray or electron system or undertake other corrective action before the equipment is again used to irradiate patients. The registrant shall also perform an output constancy check to determine whether or not the therapeutic x-ray or electron system is again in compliance with this subsection prior to utilizing the equipment to irradiate patients. A record of each output constancy check performed in accordance with this subsection, and any repairs or corrective action undertaken in compliance with this subsection, shall be maintained by the registrant for a minimum of two (2) years from the date the output constancy check, repair, or corrective action was performed. (cc) The registrant shall perform checks on treatment planning computers and dose calculation algorithms in accordance with quality assurance procedures developed by a radiation oncology physicist approved by the department. At a minimum, the quality assurance procedures shall require that the registrant do the following: (1) Verify that the output for external beam programs, including irregular fields, agree with measured beam data for test cases. (2) Ensure that any computer hardware changes have been correctly installed. (3) Ensure that any computer software changes, including beam data files, have been correctly implemented without corrupting beam data. (4) Verify that all users of treatment planning computers have been trained in the use of the computers. (dd) The registrant shall establish and maintain a written quality management plan to assure that radiation from an x-ray or electron therapy system is administered as ordered by a practitioner of the healing arts. At a minimum, the quality management plan must assure the following: (1) Prior to administration, a written order for therapeutic radiation must be prepared by a practitioner of the healing arts. Said order shall specify, at a minimum, the following: (A) The patient's name. (B) The anatomical treatment site or sites. (C) For each treatment site, treatment mode, and beam energy, the following: (i) The dose per fraction. (ii) The number of fractions. (iii) The total dose. If, in the opinion of a practitioner of the healing arts, any delay could jeopardize the health of a patient, said practitioner may verbally order therapeutic radiation, as long as the practitioner prepares a written order in accordance with this subdivision, to confirm his or her verbal orders within seventy-two (72) hours of issuing the verbal order. (2) Treatment plans and related calculations for radiation are in accordance with the written order of a practitioner of the healing arts. (3) That each administration of therapeutic radiation is in accordance with a written order of a practitioner of the healing arts. (4) That deviations from the written order of a licensed practitioner of the healing arts in excess of ten percent (10%) of the daily prescribed dose is identified, evaluated, and the findings communicated to the practitioner of the healing arts. (ee) The registrant shall review the radiation oncology chart of patients subjected to irradiation from a therapeutic x-ray or electron system in accordance with written quality assurance procedures developed by a radiation oncology physicist approved by the department. At a minimum, the written quality assurance procedures must require the following: (1) That the documented monitor units used for each field is [sic., are] in conformance with calculations. (2) That the therapeutic x-ray or electron system operator initials the treatment documentation for each patient he or she treats, each day. (3) The daily radiation dose and the cumulative radiation dose is [sic., are] recorded. (4) Each written order for therapy treatment is being followed. (5) The total prescribed dose for each treatment site is appropriately indicated. (ff) The registrant shall submit a written report to the commissioner of any misadministration within fifteen (15) days of discovery of the misadministration. The report shall contain the following: (1) State the name and address of the registrant. (2) State the name of the practitioner of the healing arts who prescribed the x-ray or electron therapy at issue. (3) State the name of the individual who was improperly irradiated, or the name of that individual's parent or guardian, if applicable. (4) Briefly describe the nature of the misadministration and any resultant effect on the individual who was improperly irradiated. (5) Describe the actions taken by the registrant to prevent a recurrence of similar misadministrations. (6) State what information has been presented to the individual who was improperly irradiated, or to that individual's parent or guardian, if applicable. A copy of the report shall be maintained by the registrant for at least five (5) years after the date of the misadministration. (gg) If possible, within twenty-four (24) hours of discovery of a misadministration, the registrant shall notify the individual who has been improperly irradiated, or that individual's parent or guardian, if applicable, about the misadministration, unless, in the opinion of a practitioner of the healing arts, such notification would be harmful to that individual. Also, within twenty-four (24) hours of discovery of a misadministration, the registrant shall notify the referring practitioner of the healing arts about the misadministration. At a minimum, the notifications shall briefly describe the nature of the misadministration and any resultant effect on the individual who was improperly irradiated. (hh) A therapeutic x-ray system shall not be used to administer radiation therapy unless it complies with subsections (u), (y), (z), and (aa) through (cc).