Section 216-RICR-40-20-5.2 - DefinitionsA. Whenever used in this Part, the following terms must be construed as follows:1. "Absorbed dose" or "D" means the mean energy imparted by ionizing radiation to matter. Absorbed dose is determined as the quotient of dE by dM, where dE is the mean energy imparted by ionizing radiation to matter of mass dM. The units of absorbed dose is the gray (Gy). One gray (Gy) is the international system of units (SI) equivalent of one hundred (100) rads, which is equal to an absorbed dose of one (1) joule/kilogram.2. "Absorbed dose rate" means absorbed dose per unit time, for machines with timers, or dose monitor unit per unit time for electrically generated radiation producing devices.3. "Act" means R.I. Gen. Laws Chapter 23-1.3, entitled "Radiation Control."4. "Agency" means Rhode Island Radiation Control Agency (RCA), Center for Health Facilities Regulation - Radiation Control Program, Rhode Island Department of Health.5. "Air kerma" or "K" means the kinetic energy released in air by ionizing radiation. Kerma is determined as the quotient of dE by dM, where dE is the sum of the initial kinetic energies of all the charged ionizing particles liberated by uncharged ionizing particles in air of mass dM. The SI unit of air kerma is joule per kilogram and the name for the unit of kerma is the gray (Gy).6. "Authorized physician" means a physician who is qualified to be named on an Agency therapeutic radiation machine registration by satisfying the requirements of §5.3.3 of this Part.7. "Barrier" (See "Protective barrier").8. "Beam axis" means the axis of rotation of the beam limiting device.9. "Beam-limiting device" means a field defining collimator, integral to the therapeutic radiation machine, which provides a means to restrict the dimensions of the useful beam.10. "Beam monitoring system" means a system designed and installed in the radiation head to detect and measure the radiation present in the useful beam.11. "Beam scattering foil" means a thin piece of material (usually metallic) placed in the beam to scatter a beam of electrons in order to provide a more uniform electron distribution in the useful beam.12. "Bent beam linear accelerator" means a linear accelerator geometry in which the accelerated electron beam must change direction by passing through a bending magnet.13. "Changeable filters" means any filter, exclusive of inherent filtration, which can be removed from the useful beam through any electronic, mechanical, or physical process.14. "Contact therapy system" means a therapeutic radiation machine with a short target to skin distance (TSD), usually less than five (5) centimeters.15. "Conventional simulator" means any X-ray equipment designed to reproduce the geometric conditions of the radiation therapy equipment.16. "Detector" (See "Radiation detector").17. "Dose monitor unit" or "DMU" means a unit response from the beam monitoring system from which the absorbed dose can be calculated.18. "Dosimetry system" means an ion chamber and electrometer used as a dosimeter for measurement of clinical photon and electron beams with calibration coefficients determined either in air or in water and are traceable to a national primary standards dosimetry laboratory. Specialized dosimetry systems are available for detecting different radiation types.19. "Electronic brachytherapy" means a method of radiation therapy where an electrically generated low-energy source of ionizing radiation is placed in or near the tumor or target tissue to deliver a therapeutic radiation dose.20. "Electronic brachytherapy device" means the system used to produce and deliver therapeutic radiation including the X-ray tube, the control mechanism, the cooling system, and the power source.21. "Electronic brachytherapy source" means the X-ray tube component used in an electronic brachytherapy device.22. "External beam radiation therapy" means therapeutic irradiation in which the source of radiation is at a distance from the body.23. "Field-flattening filter" means a filter used to homogenize the absorbed dose rate over the radiation field.24. "Filter" means material placed in the useful beam to change beam quality in therapeutic radiation machines subject to § 5.6 of this Part.25. "Gantry" means that part of a radiation therapy system supporting and allowing movements of the radiation head about a center of rotation.26. "Gray" or "Gy" means the SI unit of absorbed dose, kerma, and specific energy imparted equal to one (1) joule per kilogram. The previous special unit of absorbed dose (rad) has been replaced by the gray. [one (1) Gy = one hundred (100) rad].27. "Half-value layer" or "HVL" means the thickness of a specified material which attenuates X-ray radiation or gamma radiation to an extent such that the air kerma rate, exposure rate or absorbed dose rate is reduced to one half (1/2) of the value measured without the material at the same point.28. "Image guided radiation therapy" or "IGRT" means a method of radiation therapy where the treatment setup and delivery are verified through imaging-based system(s).29. "Interlock" means a device preventing the start or continued operation of equipment unless certain predetermined conditions prevail.30. "Interruption of irradiation" means the stopping of irradiation with the possibility of continuing irradiation without resetting of operating conditions at the control panel.31. "Irradiation" means the exposure of a living being or matter to ionizing radiation.32. "Isocenter" means the center of the sphere through which the useful beam axis passes while the gantry moves through its full range of motions.33. "Kilovolt," "kV," "Kilo electron volt," or "keV" means the energy equal to that acquired by a particle with one (1) electron charge in passing through a potential difference of one thousand (1,000) volts in a vacuum. The current convention is to use kV for photons and keV for electrons.34. "Lead equivalent" means the thickness of the material in question affording the same attenuation, under specified conditions, as lead.35. "Leakage radiation" means radiation emanating from the radiation therapy system except for the useful beam.36. "Light field" means the area illuminated by light, simulating the radiation field.37. "mA" means milliampere.38. "Medical health physicist" means an individual who meets the qualifications of §5.3.4 of this Part or is certified by The American Board of Medical Physics in Medical Health Physics, or is certified by the American Board of Health Physics including a minimum three (3) years relevant experience in the subfield of medical health physics.39. "Megavolt," "MV," "Mega electron volt," or "MeV" means the energy equal to that acquired by a particle with one (1) electron charge in passing through a potential difference of one million (1,000,000) volts in a vacuum. The current convention is to use MV for photons and MeV for electrons.40. "Mobile electronic brachytherapy" means transportation of an electronic brachytherapy device to provide electronic brachytherapy at an address that is not the address of record.41. "Mobile therapeutic radiation machine" means a machine that is transported from one address to be used at another address, or moveable within the facility of record.42. "Monitor unit (MU)" (See "Dose monitor unit").43. "Moving beam radiation therapy" means radiation therapy with any planned displacement of radiation field or patient/human research subject relative to each other, or with any planned change of absorbed dose distribution. It includes, but is not limited to, arc, skip, conformal, intensity modulation and rotational therapy.44. "Patient" means an individual subjected to machine produced radiation for the purpose(s) of medical therapy.45. "Patient intervention" means any action by the patient or human research subject, whether intentional or unintentional, during the administration of radiation therapy that causes interference.46. "Peak tube potential" means the maximum value of the potential difference across the X-ray tube during an exposure.47. "Periodic quality assurance check" means a procedure which is performed to ensure that a previous parameter or condition continues to be valid.48. "Phantom" means an object behaving in essentially the same manner as tissue, with respect to absorption or scattering of the ionizing radiation in question.49. "Prescribed dose" means the total dose and dose per fraction as documented in the written directive. The prescribed dose is an estimation from measured data from a specified therapeutic radiation machine using assumptions that are clinically acceptable for that treatment technique and historically consistent with the clinical calculations previously used for patients treated with the same clinical technique.50. "Primary dose monitoring system" means a system which will monitor the useful beam during irradiation, and which will terminate irradiation when a pre-selected number of dose monitor units have been delivered.51. "Primary protective barrier" (see "Protective barrier").52. "Protective barrier" means a barrier of radiation absorbing material(s) used to reduce radiation exposure. The types of protective barriers are as follows:a. "Primary protective barrier" means the material, excluding filters, placed in the useful beam.b. "Secondary protective barrier" means the material which attenuates stray radiation.53. "Qualified medical physicist" means an individual qualified in accordance with §5.3.4 of this Part.54. "Quality management program" means a program providing for verification of process by written procedures addressing testing, auditing, and inspection to ensure that deficiencies, deviation, defective equipment, or unsafe practices, or a combination thereof, relating to the use, disposal, management, or manufacture of radiation devices are identified, promptly corrected, and reported to the appropriate regulatory authorities.55. "Radiation detector" means a device that, in the presence of radiation provides, by either direct or indirect means a signal or other indication suitable for use in measuring one (1) or more properties or quantities of incident radiation.56. "Radiation field" (see "Useful beam").57. "Radiation head" means the structure from which the useful beam emerges.58. "Radiation oncology safety team" means a team that must include, but is not limited to, the authorized physician, qualified medical physicist, radiation oncology therapist, and other individuals as deemed necessary by the registrant (e.g., radiation safety officer, chief medical or administrative officer, department administrator/manager, nurse). The radiation oncology safety team is responsible for the registrant's quality management program.59. "Radiation protection program" means organizational, procedural, and technical arrangements for the designation of controlled areas and supervised areas, for local rules, and for monitoring of the workplace for occupational exposure.60. "Redundant beam monitoring system" means a combination of two (2) independent dose monitoring systems in which each system is designed to terminate irradiation in accordance with a pre-selected number of dose monitor units.61. "Registrant" means any person who is registered with the Agency and is legally obligated to register with the Agency pursuant to this Subchapter and the Act.62. "Registration" means registration with the Agency pursuant to this Subchapter and the Act.63. "Safety assessment program" means a plan prepared by the registrant to address protection and safety for radiation practices within the facility and includes, but is not limited to, consideration of the design, construction, and operation of therapeutic radiation machines and related facilities and equipment as they pertain to normal and potential exposure. It also includes consideration of management systems and procedures to safely handle therapeutic radiation machines, to operate equipment, to monitor radiation protection, to implement a quality assurance program, and to handle emergencies.64. "Scattered radiation" means ionizing radiation emitted by interaction of ionizing radiation with matter, the interaction being accompanied by a change in direction of the radiation. Scattered primary radiation means that scattered radiation which has been deviated in direction only by materials irradiated by the useful beam.65. "Secondary dose monitoring system" means a system which will terminate irradiation in the event of failure of the primary dose monitoring system.66. "Shutter" means a device attached to the tube housing assembly which can totally intercept the useful beam, and which has a lead equivalency not less than that of the tube housing assembly.67. "Sievert" or "Sv" means the SI unit of dose equivalent. The unit of dose equivalent is the joule per kilogram. The previous special unit of dose equivalent (rem) is being replaced by the sievert. [one (1) Sv = one hundred (100) rem].68. "Simulator (radiation therapy simulation system)" means any X-ray system intended for localizing the volume to be exposed during radiation therapy and establishing the position and size of the therapeutic irradiation field.69. "Source" means the region and/or material from which the radiation emanates.70. "Source-skin distance" or "SSD" (See "Target-skin distance").71. "Stationary beam radiation therapy" means radiation therapy without displacement of one (1) or more mechanical axes relative to the patient/human research subject during irradiation.72. "Stray radiation" means the sum of leakage and scattered radiation.73. "Survey instruments" means detectors used for measuring radiation exposure levels. Specialized survey instruments are available for detecting different radiation types.74. "Target" means that part of an X-ray tube or accelerator onto which is directed a beam of accelerated particles to produce ionizing radiation or other particles.75. "Target-skin distance" or "TSD" means the distance measured along the beam axis from the center of the front surface of the X-ray target and/or electron virtual source to the surface of the irradiated object or patient/human research subject.76. "Tenth-value layer" or "TVL" means the thickness of a specified material which attenuates X-radiation or gamma radiation to an extent such that the air kerma rate, exposure rate or absorbed dose rate is reduced to one-tenth (1/10) of the value measured without the material at the same point.77. "Termination of irradiation" means the stopping of irradiation in a fashion which will not permit continuance of irradiation without the resetting of operating conditions at the control panel.78. "Therapeutic radiation machine" means X-ray or electron-producing equipment designed and used for external beam radiation therapy. For the purpose of this Part, devices used to administer electronic brachytherapy must also be considered therapeutic radiation machines.79. "Treatment frequency" means fractions per calendar day, minimum interfraction interval, coordination with systemic therapy (if applicable), or plan delivery sequencing. Also known as fractionation schedule.80. "Treatment modality" means electron, photon, or charged particle modes of delivery.81. "Treatment site" means the anatomical description of the tissue intended to receive a therapeutic radiation dose, as prescribed in a written directive.82. "Treatment technique" means a technique that includes, but is not limited to, anteroposterior [AP], posteroanterior [PA], right and/or left laterals, right and/or left anterior or posterior oblique, tangents, 4-field, 3-field, en face, dynamic conformal arc therapy [DCAT], intensity modulated radiation therapy [IMRT], volumetric modulated arc therapy [VMAT], stereotactic radiosurgery [SRS], stereotactic body radiation therapy [SBRT], or beam configuration approved by the authorized physician.83. "Tube" means an X-ray tube, unless otherwise specified.84. "Tube housing assembly" means the tube housing with tube installed. It includes high-voltage and/or filament transformers and other appropriate elements when such are contained within the tube housing.85. "Useful beam" means the radiation emanating from the tube housing port or the radiation head and passing through the aperture of the beam limiting device when the exposure controls are in a mode to cause the therapeutic radiation machine to produce radiation.86. "Virtual simulator" means an imaging unit used in conjunction with relevant software which recreates the treatment machine, and that allows import, manipulation, display, and storage of images from CT and/or other imaging modalities.87. "Virtual source" means a point from which radiation appears to originate.88. "Wedge filter" means a filter which effects continuous change in transmission over all or a part of the useful beam.89. "Written directive" means an order in writing for the administration of radiation to a specific patient or human research subject, as specified in §5.5.1 of this Part.90. "X-ray tube" means any electron tube which is designed to be used primarily for the production of X-rays.216 R.I. Code R. 216-RICR-40-20-5.2
Adopted effective 1/1/2019
Amended effective 5/25/2022
Amended effective 11/27/2023