105 CMR 120.440
Appendix A: Information on Radiation Shielding Required for Plan Reviews
I. 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.
II. 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 one 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 blueprint/drawing indicating: scale [0.25 inch = one 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 105 CMR 120.211.
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.
F. At least one example calculation which shows the methodology used to determine the
amount of shielding required for each physical condition [ie: 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.
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III. THERAPEUTIC RADIATION MACHINES OVER 150 kV
In addition to the requirements listed in Section I above, therapeutic radiation machine facilities
which 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 [ie: 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 one 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 blueprint/drawing [including both floor plan and elevation views] indicating relative
orientation of the therapeutic radiation machine, scale [0.25 inch = one 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 [ie: room may be designed for six MV unit although only a four 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.
G. At least one example calculation which shows the methodology used to determine the
amount of shielding required for each physical condition [ie: 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.
(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.
IV. NEUTRON SHIELDING
In addition to the requirements listed in Section III above, therapeutic radiation machine facilities
which are capable of operating above ten 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 [ie: 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.
(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 which will be used to verify the adequacy of all neutron
shielding installed in the facility.
V. 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 0.1-100 MeV Particle
Accelerator Facilities" (1977).
C. NCRP Report 79, "Neutron Contamination from Medical Electron Accelerators" (1984).