The Design of Diagnostic Medical Facilities where ... - ResearchGate

For general rooms, the lead equivalence of the screen is typically 2 mm although 3-4 mm or more may be
required for angiography suites and multi-slice CT installations. The minimum height should be 2 m (BIR,
2000). The upper half is generally transparent and made of lead glass or lead acrylic to permit the operator
to have a panoramic view of the room, good visibility of the patient, the X‐ray tube, warning lights on
equipment (where fitted) and the doors. The design must ensure integrity at the joints between the panel
sections, and the panels and lead glass (see Appendix E, Fig. E.7). Joints should be adequately shielded and
the lead glass sheets/panels should be overlapped by 30-40 mm (BIR, 2000) or protected by a shielded joint
(Photo 6.5). The screen should be marked with the lead equivalent thickness. Exceptionally, in some rooms a
mirror may be necessary to enable the operator to view entrance doors, which may be out of direct sight. In
addition to protecting the operator, the console may sometimes be required to protect unused films in
cassettes or CR plates. If this is the case, it must be taken into consideration when specifying the lead
equivalence.
Photo 6.5 Lead plywood on lead lined batons
Lead
Lead
(Photographs courtesy of Wardray Premise Ltd)
The control panel/operator’s console effectively becomes a separate room in CT and interventional suites (see
Sections 3.4.2 and 3.5). The operator(s) then view the room through a panoramic window composed of lead
glass or acrylic as described above. The window frames must be shielded and there must be sufficient overlap
of the shielding between the window and window frames and between the window frames and the wall as
described above (see Appendix E, Fig. E.7). There will normally be a door leading from the operator’s room
to the controlled area which must be protected as described in Section 6.3.3.
In designing operator areas or rooms a number of operational aspects have a strong influence on the level
of shielding required. If access to these areas is restricted to occupationally exposed workers the design
constraint of 1 mSv per year can be used. This is likely to be the case in a general radiography room. If, on
the other hand, the area is to be used as a general consultation, teaching, cardiac monitoring and reporting
area, non-designated staff will regularly be in attendance. This will often be the case with CT and interventional
suites. In such cases the design constraint for a member of the public, 0.3 mSv per year must be used (see
The Design of Diagnostic Medical Facilities where Ionising Radiation is used 83