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Room design features

Protection systems are required to reduce dental staff exposure to radiation. Watch Graham Ramsden explain more.
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In this step, I’m going to show you how doses to dental staff can be restricted through the effective design of radiography facilities. In particular, I’m going to cover the room design and the provision of warning lights and signs. Before we do that, I’d like to remind you of the hierarchy of control measures that is set out in regulation 9(2) of IRR17, which requires the restriction of exposure to be achieved primarily through the use of engineering controls, design and safety features, as well as the provision of warning devices. Where this alone isn’t sufficient to restrict exposures, admin controls such as safe working procedures should be provided.
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Personal protective equipment such as lead aprons should only be used where there is further scope to restrict exposures and is not acceptable as a primary means of restricting the radiation exposure of staff. The other thing that we’ll remind you about is that you should have received advice from your RPA on the room plans prior to having an X-ray set installed. So having reminded you of these things, let’s look at what protection measures should be inherent in a facility, starting with wall construction. In general, solid walls made of brick, concrete blocks, and breeze blocks are most likely to provide sufficient protection. In some cases, lightweight blocks or stud partition walls may also be satisfactory.
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When it comes to doors, a standard door will probably not provide sufficient protection, particularly if it is in close proximity to the X-ray set or if the main X-ray beam of an intraoral X-ray set is directed towards it. External windows, on the other hand, will not usually require shielding, as it is unlikely that the area on the outside of the window would often be occupied. When designing an X-ray room, the best position for the operator is generally standing outside the room at the entrance.
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Or, if the operator has to stand inside the room to operate an intraoral, panoramic, or cephalometric X-ray set, this must be at least 1.5 metres from the X-ray head and patient, and well away from the path of the main X-ray beam. In the majority of cases with cone beam CT equipment, the higher levels of scattered radiation will mean that the operator has to stand outside the radiography room or behind a shielded screen if remaining inside the room. If the operator stands outside the room, it must still be possible to observe the patient. The operator must also be able to see the X-ray equipment warning lights or hear the audible signal during the exposure.
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These requirements could be met by either installing a window, which may need to be shielded, or by the installation of a video camera and monitor system. When additional shielding is required, the amount needed can vary from just a further layer of a standard plaster board applied to a stud partition wall to lead sheet, leaded glass, or barium plaster. There are also more specialist products such as barium plaster boards available. The siting of equipment control panels, exposure switches and power isolation switches, should also be considered carefully at the planning stage.
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Control panels or exposure switches would normally be sited close to the operator position, and there should be a means of turning off the mains power immediately accessible to the operator should the exposure need to be terminated in an emergency. When a control panel is sited outside a radiography room, the potential for the X-ray equipment to be operated by unauthorised persons must be considered. Some equipment is provided with a key-operated isolater and the control panels for some equipment can be isolated by pressing a certain combination of its buttons. If neither of these options is available, the control panel should be sited inside a lockable box. Where X-ray equipment is software controlled, e.g.
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with some panoramic, cephalometric, and cone beam CT equipment, it is satisfactory to password protect the computer to prevent unauthorised use if that is effective in preventing X-ray exposures. In addition to the safety warning devices on X-ray sets, there are certain requirements for warning lights and signs outside radiography rooms. In week four, we’ll cover the regulatory requirements for the designation of a radiation controlled area while working with X-rays. Where the whole room is a controlled area, which will be the majority of situations, warning signs or lights must be posted or illuminated outside the room at every accessible entrance whenever the equipment is in a state of readiness to emit X-rays.
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For most intraoral X-ray sets, this will be whenever the power is switched on. For panoramic, cephalometric, or cone beam CT equipment, where their exposure controls can be disabled by entering a password on the controlling software, this will be whenever the power is on, the imaging software has been set up for an exposure and the password protection removed. At all other times, the warning signs or lights indicating that a controlled area exists must be removed, covered, or unlit. The example notice shown has a yellow radiation trefoil sign accompanied by the wording controlled area X-rays. And next to it, the no unauthorised entry sign.
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An alternative would be to provide an automatic warning light that illuminates when power is supllied to the X-ray set. If the light itself doesn’t have the required wording, it should be given on an accompanying sign. Dental practices need to decide which is the best option to use for their controlled areas, either warning signs or lights, on a case by case basis, and they should take advice from their RPA on this. For instance, it might not be possible to link warning lights to an X-ray set so that they automatically illuminate when the equipment is ready to emit X-rays, especially where passwords are used to disable the controls when the equipment isn’t being used.
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In some situations, such as when there are multiple entrances to a radiography room, it may be more practical to lock doors to stop entry to the room rather than providing signs on each door, all of which would need to be changed before and after radiography.

The video covers the importance of design of radiography facilities within dental practices.

Graham Ramsden discusses room design as well as other safety provisions for radiography facilities within dental practices. These aspects are important to reduce staff exposure to radiation. The protection measures that should be in place for dental practices are covered, including wall construction, warning lights and signals and restriction of access.

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Dental Radiography: Radiation Protection in Dental Practice

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