C.M.R. 10, 144, ch. 220, pt. X, app 144-220-X-A
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).
C.M.R. 10, 144, ch. 220, pt. X, app 144-220-X-A