216 R.I. Code R. 216-RICR-40-20-5.6

Current through December 26, 2024

Section 216-RICR-40-20-5.6 - Therapeutic Radiation Machines of Less Than 500 kV

Documentation from the manufacturer and installer that the therapeutic radiation machine was manufactured and installed in accordance with most current applicable International Electrotechnical Commission (IEC) standards in effect at the time of manufacturing/installation must be sufficient to demonstrate compliance with the applicable requirements of §§5.6.1 through 5.6.13 of this Part.

5.6.1Leakage Radiation

A. When the X-ray tube is operated at its maximum rated tube current for the maximum kV, the leakage air kerma rate must not exceed the value specified at the distance specified for that classification of therapeutic radiation machine:

1. Five to fifty (5 - 50) kV Systems. The leakage air kerma rate measured at any position five (5) centimeters from the tube housing assembly must not exceed one (1) mGy (one hundred (100) mrad) in any one (1) hour.

2. Greater than fifty (>50) and < five hundred (500) kV Systems. The leakage air kerma rate measured at a distance of one (1) meter from the target in any direction must not exceed one (1) cGy in any one (1) hour. This air kerma rate measurement may be averaged over areas no larger than one hundred square centimeters (100 cm²). In addition, the air kerma rate at a distance of five (5) centimeters from the surface of the tube housing assembly must not exceed thirty (30) cGy per hour.

3. For each therapeutic radiation machine, the registrant must determine, or obtain from the manufacturer, the leakage radiation existing at the positions specified in §§5.6.1(A)(1) and (2) of this Part for the specified operating conditions. Records on leakage radiation measurements must be maintained in an auditable form at the installation for inspection by the Agency.

5.6.2Permanent Beam Limiting Devices

Permanent diaphragms or cones used for limiting the useful beam must provide at least the same degree of attenuation as required for the tube housing assembly.

5.6.3Adjustable or Removable Beam Limiting Devices

A. All adjustable or removable beam limiting devices, diaphragms, cones or blocks must not transmit more than five percent (5%) of the useful beam for the most penetrating beam used.

B. When adjustable beam limiting devices are used, the position and shape of the radiation field must be indicated by a light field.

5.6.4Filter System

A. The filter system must be so designed that:

1. Filters cannot 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 must not exceed one (1) cGy per hour at one (1) meter under any operating conditions; and

4. Each filter must be marked as to its material of construction and its thickness.

5.6.5Tube Immobilization

A. The X-ray tube must be so mounted that it cannot accidentally turn or slide with respect to the housing aperture; and

B. The tube housing assembly must be capable of being immobilized for stationary portal treatments.

5.6.6Source Marking

The tube housing assembly must be so marked that it is possible to determine the location of the source to within five (5) millimeters, and such marking must be readily accessible for use during calibration procedures.

5.6.7Beam Block

Contact therapy tube housing assemblies must have a removable shield of material, equivalent in attenuation to one half (0.5) millimeters of lead at one hundred (100) kV, which can be positioned over the entire useful beam exit port during periods when the beam is not in use.

5.6.8Timer

A. A suitable irradiation control device must be provided to terminate the irradiation after a pre-set time interval.

B. A timer which has a display must be provided at the treatment control panel. The timer must have a pre-set time selector and an elapsed time or time remaining indicator.

C. The timer must be a cumulative timer which activates with an indication of "BEAM-ON" and retains its reading after irradiation is interrupted or terminated. After irradiation is terminated and before irradiation can be reinitiated, it must be necessary to reset the elapsed time indicator.

D. The timer must terminate irradiation when a pre-selected time has elapsed, if any dose monitoring system present has not previously terminated irradiation.

E. The timer must permit accurate pre-setting and determination of exposure times as short as one (1) second.

F. The timer must not permit an exposure if set at zero (0).

G. The timer must 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 H. Timer must be accurate to within one percent (1%) of the selected value or one (1) second, whichever is greater.

5.6.9Control Panel Functions

A. The control panel, in addition to the displays required by other provisions in § 5.6 of this Part, must 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. The means for terminating an exposure at any time.

5. An access control device which will prevent unauthorized use of the therapeutic radiation machine; and

6. A positive display of specific filter(s) in the beam.

5.6.10Multiple Tubes

A. When a control panel may energize more than one (1) X-ray tube:

1. It must be possible to activate only one (1) X-ray tube at any time;

2. There must be an indication at the control panel identifying which X-ray tube is activated; and

3. There must be an indication at the tube housing assembly when that tube is energized.

5.6.11Target-to-Skin Distance (TSD)

There must be a means of determining the central axis TSD to within one (1) centimeter and of reproducing this measurement to within two (2) millimeters thereafter.

5.6.12Shutters

Unless it is possible to bring the X-ray output to the prescribed exposure parameters within five (5) seconds after the X-ray "ON" switch is energized, the beam must be attenuated by a shutter having a lead equivalency not less than that of the tube housing assembly. In addition, after the unit is at operating parameters, the shutter must be controlled by the operator from the control panel. An indication of shutter position must appear at the control panel.

5.6.13Low Filtration X-ray Tubes

Each therapeutic radiation machine equipped with a beryllium or other low-filtration window must be clearly labeled as such upon the tube housing assembly and must be provided with a permanent warning device on the control panel that is activated when no additional filtration is present, to indicate that the dose rate is very high.

5.6.14Facility Design Requirements for Therapeutic Radiation Machines Capable of Operating in the Range 50 kV to 500 kV

A. In addition to shielding adequate to meet requirements of §5.9.1 of this Part, the treatment room must meet the following design requirements:

1. Aural Communication. Provision must be made for continuous two (2) way aural communication between the patient/human research subject and the operator at the control panel.

2. Viewing Systems. Provision must be made to permit continuous observation of the patient/human research subject during irradiation and the viewing system must be so located that the operator can observe the patient/human research subject from the control panel. The therapeutic radiation machine must not be used for patient/human research subject irradiation unless at least one (1) viewing system is operational.

5.6.15Additional Requirements

A. Treatment rooms which contain a therapeutic radiation machine capable of operating above one hundred fifty (150) kV must meet the following additional requirements:

1. All protective barriers must be fixed except for entrance doors or beam interceptors.

2. The control panel must be located in a location that ensures compliance with Part 1 of this Subchapter.

3. Interlocks must be provided such that all entrance doors, including doors to any interior booths, must be closed before treatment can be initiated or continued. If the radiation beam is interrupted by any door opening, it must not be possible to restore the machine to operation without closing the door and reinitiating irradiation by manual action at the control panel; and

4. When any door referred to in §5.6.15(A)(3) of this Part is opened while the X-ray tube is activated, the air kerma rate at a distance of one (1) meter from the source must be reduced to less than one (1) mGy (one hundred (100) mrad) per hour.

5.6.16Acceptance Testing, Commissioning, and Full Calibration Measurements

A. Acceptance testing, commissioning, and full calibration of a therapeutic radiation machine subject to § 5.6 of this Part must be performed by, or under the direct supervision of, a Qualified Medical Physicist.

1. Acceptance testing and commissioning must be performed in accordance with current published recommendations from a recognized national professional association with expertise in the use of therapeutic radiation technologies. In the absence of a protocol published by a recognized national professional association, the manufacturer's protocol or equivalent quality, safety, and security protocols, must be followed. Acceptance testing and commissioning must be conducted before the first medical use following installation or reinstallation of the therapeutic radiation machine.

2. Full calibration must be performed in accordance with current published recommendations from a recognized national professional association with expertise in the use of therapeutic radiation technologies. In the absence of a protocol published by a recognized national professional association, the manufacturer's protocol or equivalent quality, safety, and security protocols, must be followed. All applicable parameters (for all energies), and the calibration report, must be completed:

a. Before the first medical use following installation or reinstallation of the therapeutic radiation machine; and

b. At intervals not exceeding thirteen (13) calendar months; and

c. Before medical use under the following conditions:

(1) Whenever quality assurance check measurements indicate that the radiation output differs by more than five percent (5%) from the value obtained at the last full calibration and the difference cannot be reconciled; and

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

3. Notwithstanding the requirements of §5.6.16(A)(2)(c) of this Part:

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; and

b. If the repair, replacement or modification does not affect all energies, full calibration must be performed on the affected energy that is in most frequent clinical use at the facility. The remaining energies may be validated with quality assurance check procedures against the criteria in §5.6.16(A)(2)(c)(1) of this Part.

B. The registrant must maintain a record of each calibration in an auditable form for the duration of the registration. The record must include the calibration reports, the date of the calibration, the manufacturer's name, model number, and serial number for both the therapeutic radiation machine and the X-ray tube, the model numbers and serial numbers of the instruments used to calibrate the therapeutic radiation machine, and the signature of the Qualified Medical Physicist responsible for performing the calibration.

5.6.17Quality Assurance Checks

A. Periodic quality assurance checks must be performed on therapeutic radiation machines subject to § 5.6 of this Part, which are capable of operation at greater than or equal to fifty (50) kV.

B. To satisfy the requirement of §5.6.17(A) of this Part, periodic quality assurance checks must meet the following requirements:

1. The registrant must perform periodic quality assurance checks in accordance with written procedures established by the Qualified Medical Physicist and must be performed in accordance with current published recommendations from a recognized national professional association with expertise in the use of therapeutic radiation technologies. In the absence of a protocol published by a recognized national professional association, the manufacturer's protocol or equivalent quality, safety, and security protocols, must be followed; and

2. The periodic quality assurance check procedures must specify the frequency at which tests or measurements are to be performed. The periodic quality assurance check procedures must specify that the periodic quality assurance check must be performed during the calibration specified in §5.6.16(A) of this Part. The acceptable tolerance for each parameter measured in the periodic quality assurance checks, when compared to the value for that parameter determined in the calibration specified in §5.6.16(A) of this Part, must be stated.

C. The cause for a parameter exceeding a tolerance set by the Qualified Medical Physicist and consistent with nationally recognized standards must be investigated and corrected before the system is used for patient/human research subject irradiation.

D. Whenever a periodic quality assurance check indicates a significant change in the operating characteristics of a system, as specified in the Qualified Medical Physicist's periodic quality assurance check procedures, the system must be recalibrated, as required in §5.6.16(A) of this Part.

E. The registrant must use the dosimetry system described in §5.11.5 of this Part to make the periodic absolute dose measurement.

F. The registrant must have the Qualified Medical Physicist review and sign the results of each radiation output quality assurance check within fifteen (15) days of the date that the check was performed.

G. The registrant must ensure that monthly safety quality assurance checks of therapeutic radiation machines subject to § 5.6 of this Part are performed at intervals not to exceed thirty-six (36) days.

H. Notwithstanding the requirements of §§5.6.17(F) and (G) of this Part, the registrant must ensure that no therapeutic radiation machine is used to administer radiation to humans unless the quality assurance checks required by §§5.6.17(F) and (G) of this Part have been performed at intervals not to exceed the thirty-six (36) day period immediately prior to said administration.

I. To satisfy the requirement of §5.6.17(G) of this Part, monthly safety quality assurance checks must ensure proper operation of:

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

2. Proper operation of the "BEAM-ON" and termination switches;

3. Beam condition indicator lights on the access door(s), control console, and in the radiation therapy room;

4. Viewing and aural systems;

5. If applicable, electrically operated treatment room doors from inside and outside the treatment room;

J. The registrant must maintain a record of each quality assurance check in an auditable form for three (3) years. The record must include the date of the quality assurance check, the manufacturer's name, model number, and serial number for the therapeutic radiation machine, the manufacturer's name, model number, serial number, and calibration report of the instrument(s) used to measure the radiation output of the therapeutic radiation machine, and the signature of the individual who performed the quality assurance check.

5.6.18Operating Procedures

A. The therapeutic radiation machine must not be used for irradiation of patients/human research subjects unless the requirements of §§5.6.16 and 5.6.17 of this Part have been met.

B. Therapeutic radiation machines must not be left unattended unless secured pursuant to §5.6.9(A)(5) of this Part.

C. When a patient/human research subject must be held in position for radiation therapy, mechanical support or restraints devices must be used.

D. The tube housing or any other part of the imaging assembly must not be held by an individual or patient during operation unless the assembly is designed to require such holding and the peak tube potential of the system does not exceed fifty (50) kV. In such cases, the holder must wear protective gloves and apron of not less than one half (0.5) millimeters lead equivalency at one hundred (100) kV.

E. A copy of the current operating and emergency procedures must be maintained at the therapeutic radiation machine control console; and

F. No individual other than the patient/human research subject must be in the treatment room during exposures from therapeutic radiation machines operating above one hundred fifty (150) kV. At energies less than or equal to one hundred fifty (150) kV, any individual, other than the patient/human research subject, in the treatment room must be protected by a barrier sufficient to meet the requirements of §1.7.1 of this Subchapter.

5.6.19Possession of Survey Instrument(s)

Each facility location authorized to use a therapeutic radiation machine in accordance with § 5.6 of this Part 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 ten (10) µSv (one (1) mrem) per hour to ten (10) mSv (one thousand (1,000) mrem) per hour or exposure rates over the range five hundred (500) uR/h to five (5) R/h. The survey instrument(s) must be operable and calibrated in accordance with § 5.11 of this Part.

216 R.I. Code R. 216-RICR-40-20-5.6

Adopted effective 1/1/2019
Amended effective 5/25/2022
Amended effective 11/27/2023