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

3.1.3 Computed Tomography (CT)
CT allows cross sectional imaging which was traditionally of the single ‘snap-shot’ form of the head or body.
Modern CT systems produce multiple slices, enable faster three-dimensional imaging, and allow for real-time
tracking of events as in fluoroscopy. These systems have greatly enhanced the clinical value of CT and also
allow for much more rapid patient scanning. For both reasons the workload in CT rooms has increased and
the radiation levels in the vicinity of a CT scanner are possibly higher than for any other imaging modality.
Staff are not generally expected to be in the vicinity of the patient during procedures, so the mechanisms of
radiation protection include the operator screen and the room size approaches already mentioned. However,
the functions accommodated in the operator area are greatly expanded and often include direction and
analysis of the examination by the radiologist as it happens, and observation of the results by the referring
clinical team. Thus the operator’s cubicle in effect acquires a consultation, reporting and analysis function
and occupies a considerable area. There is normally a panoramic window and a door from this area to the
CT room.
3.1.4 Shared function rooms
There are an increasing number of situations involving rooms with shared functions, one of which has a
radiological component. At the extreme upper level of this range are operating theatres for vascular
procedures which also have full permanent fixed radiological equipment installed. However, more commonly,
these applications involve low-dose fluoroscopy for short time periods – e.g. during or following orthopaedic
procedures. By comparison with conventional radiological practice, a large number of staff may be present
in the room at the time. Because of the relatively low doses, radiation protection requirements are generally
less demanding than in the other facilities described above. However the large number of staff, not all of
whom will be trained in radiation protection, presents special problems. In practice a combination of mobile
shields, staff withdrawing from the immediate area and limited structural shielding can usually provide a
good solution. However, the design of these areas is generally approached on a case by case basis. In
addition, the number and type of these areas is increasing, and now routinely includes the Intensive Care,
High Dependency, Theatre, and Emergency Medicine environments (Section 3.6).
3.2 Some general comments on shielding
From the point of view of providing shielding at the room boundaries, it is important to weigh up whether
it is more economical to maximise space or install more structural shielding. For example, it may be possible
to designate a relatively large space for an X‐ray room, and as a result of the increased distances to the
occupants of nearby areas the shielding requirements can be significantly reduced. The cost and practical
implications of distance versus shielding should be considered in optimising the design solution. This will be
considered further in Chapter 5 and may be particularly important with some newer techniques with very
demanding shielding requirements. From the point of view of providing for those who must work within the
controlled or supervised areas that coincide with the room boundaries, there are three approaches to
providing protection that impact on room design or equipment specification. These are:
• Fixed screen: This is a screen which attenuates radiation and behind which the operator console and any
other necessary operator control systems (e.g. emergency stop switch) are located. Where the design
allows, the screen should be positioned so that it protects the staff entry door and staff can enter and
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The Design of Diagnostic Medical Facilities where Ionising Radiation is used