3.9.
Paragraph 3.51 of GSR Part 3 [3] establishes the broad requirements to be met when choosing a location to use a radiation generator, and these are relevant to the design of a radiology facility. Provisions for the incorporation of radiation protection and safety features are best made at the facility design stage (e.g. for X ray rooms and other related rooms). The siting and layout should take into account the types of radiological procedure, workload and patient flow, both within the radiology facility and, in cases where the radiology facility is part of a larger hospital or medical centre, within other departments of the facility. Guidance on setting up diagnostic radiology and interventional radiology facilities is given in Refs [52–55].
3.10.
The three factors relevant to dose reduction (time, distance and shielding) should be combined in the design to optimize occupational radiation protection and public radiation protection. Larger rooms are preferable to allow easy access for patients on bed trolleys. At the same time, they allow for easier patient positioning and facilitate both equipment and patient movement during the procedure, which, in the case of fluoroscopy and image guided interventional procedures, helps to reduce time and exposure. Larger rooms will also reduce the levels of secondary radiation (due to scattering and leakage) potentially reaching areas occupied by staff and public areas, typically reducing the level of shielding required.
3.11.
Shielding requirements should be tailored to meet any national requirements and to suit the practice requirements based on the intended patient workload and the types of examination to be performed. Further assessments should be undertaken when the intended use of a room changes, X ray equipment is upgraded, underlying procedures or patient workload changes, or the surrounding room occupancy is altered.
3.12.
At the design stage, the use of both structural and ancillary protective barriers to provide shielding should be considered. In rooms using fluoroscopy with staff working close to the patients, such as rooms for image guided interventional procedures, ceiling mounted protective screens and table mounted leaded curtains should be installed. Such ancillary protective barriers for image guided interventional procedures should be part of the initial facility plan, and should be designed so as not to interfere with the medical procedure (e.g. sterility requirements). Wall shielding should be at least 2 m high, and any doors and viewing windows in walls or doors should have at least the same lead equivalence as the minimum shielding specifications for the shielded wall or barrier in which they are located. Due consideration should be given to the provision of floor and ceiling shielding when rooms immediately below and above the X ray installation are occupied. All penetrations and joints in shielding should be arranged so that they are equally as effective in shielding radiation. More details with respect to structural shielding are given in paras 3.18–3.24.
3.13.
General safety features of radiography, mammography, CT and fluoroscopy rooms include the following:
A barrier should be placed at the control console to shield staff to the extent that they do not need to wear protective clothing while at the console. This is particularly important in mammography, where structural shielding in walls, ceiling and floor might not be deemed necessary.
In radiography, all possible intended directions of the X ray beam should be taken into consideration in the room design so that the X ray beam cannot be directed at any area that is not shielded and which could lead to potentially unacceptable doses being received in this area.
The doors should provide protective shielding for secondary radiation and should be shut when the X ray beam is on. In radiography, the X ray room should be designed so as to avoid the direct incidence of the X ray beam on the access doors.
The medical radiation technologist should be able to clearly observe and communicate with the patient at all times during an X ray diagnostic procedure.
3.14.
Signs and warning lights, preferably positioned at eye level, should be used at the entrances of controlled areas and supervised areas to prevent inadvertent entry (see also paras 3.279 and 3.280 on control of access). For controlled areas, para. 3.90(c) of GSR Part 3 [3] requires the use of the basic ionizing radiation symbol recommended by the International Organization for Standardization (ISO) [56]. The signs should be clear and easily understandable. Warning lights, such as illuminated or flashing signs, as appropriate, should be activated when radiation is being produced inside the controlled area or supervised area. Door interlocks are not appropriate in X ray diagnostic radiological procedures because if the X ray beam is stopped, the medical procedure may have to be repeated.
3.15.
A stable power supply should be available. An emergency diesel power generator might not be sufficiently stable to power a CT or interventional radiology suite and should not be relied upon. An uninterruptible power supply or battery backup systems should be installed to capture the active information at the time of the outage and to shut down all software in a controlled manner. Servers should be programmed to shut down automatically when the power supply is interrupted.
3.16.
The design of the facility should include an air conditioning system sufficient to maintain the temperature in the examination room (and sometimes in areas with computer equipment and detectors) within the parameters defined by the equipment manufacturers, but consistent with health and safety requirements for temperature and humidity.