Dimov A, Vassileva J
Laboratory for Dosimetry and Quality Control at Medical Exposure, National Centre of Radiobiology and Radiation Protection, 132 Kliment Ohridsky blvd., Sofia 1756, Bulgaria.
Radiat Prot Dosimetry. 2008;129(1-3):123-6. doi: 10.1093/rpd/ncn138. Epub 2008 May 10.
The aim of this study is to assess the physical properties of a recently installed digital fluoroscopy unit, Axiom Iconos R200 unit (Siemens, Germany), including image quality and patient dose. Image quality parameters and patient doses were measured at various fields of view (FOV) and frame rates. The entrance surface dose rate (ESDR) was measured using standard 30 x 30 cm2 polymethylmethacrylate (PMMA) phantom with different thicknesses. The ESDR was measured using a 20 cm PMMA and largest FOV ranged from 1.1 to 8.2 mGy min(-1) for different frame rates available. The low-contrast sensitivity varied from 1.8 to 6.6%, as the limiting spatial resolution changes from 1.25 to 2.24 ln mm(-1) for the different magnifications, frame rates and phantom thicknesses. This study shows the weak points of the standard quality control protocols. The additional image quality and dose assessments revealed the existing potential for optimisation of the system.
