Antiscatter grid

High speed systems, high kV, short duration exposures, the use of additional filters and the avoidance of antiscatter grids are recommended. It is not always easy to do this. The alteration of equipment may need senior technical advice. If the equipment is used for both adults and children it may not be easy to quickly place and remove the antiscatter grid. This will inevitably increase the radiation dose to the paediatric patients. It is a considerable advantage if at least one room in a mixed adult and paediatric department can be adapted to optimise the radiation dose to children. 

C-arm CT systems with automatic exposure control (AEG) adjust X-ray exposure parameters such that the detector entrance dose remains constant. Detector entrance dose is the X-ray dose measured behind the antiscatter grid. System dose is the detector entrance dose evaluated at a reference detector zoom format. System dose is an important set-up parameter for C-arm CT imaging protocols on Artis zee systems (Siemens AG, Healthcare Sector, Forchheim, Germany). Due to internal adjustments, the detector entrance dose for C-arm CT is about half the system dose. 

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