Code of Maine Rules › 10 - DEPARTMENT OF HEALTH AND HUMAN SERVICES › 144 - DEPARTMENT OF HEALTH AND HUMAN SERVICES - GENERAL › Chapter 220 - Rules Relating to Radiation Protection › Part X - THERAPEUTIC RADIATION MACHINES › Appendix 144-220-X-A - INFORMATION ON RADIATION SHIELDING REQUIRED FOR PLAN REVIEWS

Current through 2024-29, July 17, 2024
1. All therapeutic radiation machines.
A. Basic facility information including: name, telephone
					 number and Agency registration number of the individual responsible for
					 preparation of the shielding plan; name and telephone number of the facility
					 supervisor; and the street address including room number of the therapeutic
					 radiation machine facility. The plan should also indicate whether this is a new
					 structure or a modification to existing structure(s).
B. All wall, floor, and ceiling areas struck by the useful
					 beam shall have primary barriers.
C. Secondary barriers shall be provided in all wall, floor,
					 and ceiling areas not having primary barriers.
2. Therapeutic radiation machines up to 150 Kv
					 (photons only).
In addition to the requirements listed in Section I
					 above, therapeutic radiation machine facilities which produce only photons with
					 a maximum energy less than or equal to 150 kV shall submit shielding plans
					 which contain, as a minimum, the following additional information:
A. Equipment specifications, including the manufacturer and
					 model number of the therapeutic radiation machine, as well as the maximum
					 technique factors;
B. Maximum design workload for the facility including total
					 weekly radiation output, expressed in gray (rad) or air kerma at 1 meter, total
					 beam on time per day or week, the average treatment time per patient, along
					 with the anticipated number of patients to be treated per day or week;
C. A facility drawing indicating: scale 0.25 inch = 1 foot
					 is typical; direction of North; normal location of the therapeutic radiation
					 machine's radiation port(s); the port's travel and traverse limits; general
					 direction(s) of the useful beam; locations of any windows and doors; and the
					 location of the therapeutic radiation machine control panel. If the control
					 panel is located inside the therapeutic radiation machine treatment room, the
					 location of the operator's booth shall be noted on the plan and the operator's
					 station at the control panel shall be behind a protective barrier sufficient to
					 ensure compliance with Part D of this rule ;
D. The structural composition and thickness or
					 lead/concrete equivalent of all walls, doors, partitions, floor, and ceiling of
					 the room(s) concerned;
E. The type of occupancy of all adjacent areas inclusive of
					 space above and below the room(s) concerned. If there is an exterior wall, show
					 distance to the closest area(s) where it is likely that individuals may be
					 present; and
F. At least one example calculation which shows the
					 methodology used to determine the amount of shielding required for each
					 physical condition i.e.: primary and secondary/leakage barriers, restricted and
					 unrestricted areas, entry door(s) and shielding material in the
					 facility:
(1) If commercial software is used to generate shielding
					 requirements, please also identify the software used and the version/ revision
					 date.
(2) If the software used to generate shielding requirements
					 is not in the open literature, please also submit quality control sample
					 calculations to verify the result obtained with the software.
3. Therapeutic radiation machines over 150
					 kV.
In addition to the requirements listed in Section 1 above,
					 therapeutic radiation machine facilities that produce photons with a maximum
					 energy in excess of 150 kV and/or electrons shall submit shielding plans which
					 contain, as a minimum, the following additional information:
A. Equipment specifications including the manufacturer and
					 model number of the therapeutic radiation machine, and gray (rad) at the
					 isocenter and the energy(s) and type(s) of radiation produced i.e.: photon,
					 electron. The target to isocenter distance shall be specified;
B. Maximum design workload for the facility including total
					 weekly radiation output expressed in gray (rad) at 1 meter, total beam on time
					 per day or week, the average treatment time per patient, along with the
					 anticipated number of patients to be treated per day or week;
C. Facility drawing including both floor plan and elevation
					 views indicating relative orientation of the therapeutic radiation machine,
					 scale 0.25 inch = 1 foot is typical, type(s), thickness and minimum density of
					 shielding material(s), direction of North, the locations and size of all
					 penetrations through each shielding barrier ceiling, walls and floor, as well
					 as details of the door(s) and maze;
D. The structural composition and thickness or concrete
					 equivalent of all walls, doors, partitions, floor, and ceiling of the room(s)
					 concerned;
E. The type of occupancy of all adjacent areas inclusive of
					 space above and below the room(s) concerned. If there is an exterior wall, show
					 distance to the closest area(s) where it is likely that individuals may be
					 present;
F. Description of all assumptions that were in shielding
					 calculations including, but not limited to, design energy i.e.: room may be
					 designed for 6 MV unit although only a 4 MV unit is currently proposed, work
					 load, presence of integral beam stop in unit, occupancy and use(s) of adjacent
					 areas, fraction of time that useful beam will intercept each permanent barrier
					 walls, floor and ceiling and allowed radiation exposure in both restricted and
					 unrestricted areas; and
G. At least one example calculation which shows the
					 methodology used to determine the amount of shielding required for each
					 physical condition i.e.: primary and secondary/leakage barriers, restricted and
					 unrestricted areas, small angle scatter, entry door(s) and maze and shielding
					 material in the facility:
(1) If commercial software is used to generate shielding
					 requirements, also identify the software used and the version/ revision date;
					 and
(2) If the software used to generate shielding requirements
					 is not in the open literature, also submit quality control sample calculations
					 to verify the result obtained with the software.
4. Neutron shielding.
In addition to the requirements listed in Section III
					 above, therapeutic radiation machine facilities that are capable of operating
					 above 10 MV shall submit shielding plans, which contain, as a minimum, the
					 following additional information:
A. The structural composition, thickness, minimum density
					 and location of all neutron shielding material;
B. Description of all assumptions that were used in neutron
					 shielding calculations including, but not limited to, neutron spectra as a
					 function of energy, neutron fluence rate, absorbed dose and dose equivalent
					 (due to neutrons) in both restricted and unrestricted areas;
C. At least one example calculation, which shows the
					 methodology used to determine the amount of neutron shielding, required for
					 each physical condition i.e.: restricted and unrestricted areas, entry door(s)
					 and maze and neutron shielding material utilized in the facility:
(1) If commercial software is used to generate shielding
					 requirements, also identify the software used and the version/ revision date;
					 and
(2) If the software used to generate shielding requirements
					 is not in the open literature, also submit quality control sample calculations
					 to verify the result obtained with the software.
D. The method(s) and instrumentation that will be used to
					 verify the adequacy of all neutron shielding installed in the facility.
5. References
A. NCRP Report 49, "Structural Shielding Design and
					 Evaluation for Medical Use of X Rays and Gamma Rays of Energies Up to 10 MeV"
					 (1976).
B. NCRP Report 51, "Radiation Protection Design Guidelines
					 for 100 MeV Particle Accelerator Facilities" (1977).
C. NCRP Report 79, "Neutron Contamination from Medical
					 Electron Accelerators" (1984).