Rhode Island Code of Regulations › Title 216 - Department of health › Chapter 40 - Professional licensing and facility regulation › Subchapter 20 - Radiation › Part 5 - Therapeutic Radiation Machines › Section 216-RICR-40-20-5.2 - Definitions

Current through June 14, 2024
A. 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.