Monte Carlo simulation of a prototypical patient dosimetry system for fluoroscopic procedures
Department of Radiology
Biological and Chemical Physics | Medical Biophysics | Radiology
The purpose of this study is to investigate feasibility of a novel real-time dosimetry method for fluoroscopically guided interventions utilizing thin-film detector arrays in several potential locations with respect to the patient and x-ray equipment. We employed Monte Carlo (MC) simulation to establish the fluoroscopic beam model to determine dosimetric quantities directly from measured doses in thin-film detector arrays at three positions: A-attached to the x-ray source, B-on the couch under the patient and C-attached to the fluoroscopic imager. Next, we developed a calibration method to determine skin dose at the entry of the beam ([Formula: see text]) as well as the dose distribution along each ray of the beam in a water-equivalent patient model. We utilized the concept of water-equivalent thickness to determine the dose inside the patient based on doses measured outside of the patient by the thin-film detector array layers: (a) A, (b) B, or (c) B and C. In the process of calibration we determined a correction factor that characterizes the material-specific response of the detector, backscatter factor and attenuation factor for slab water phantoms of various thicknesses. Application of this method to an anthropomorphic phantom showed accuracy of about 1% for [Formula: see text] and up to about 10% for integral dose along the beam path when compared to a direct simulation of dose by MC.
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Citation: Phys Med Biol. 2015 Aug 7;60(15):5891-909. Epub 2015 Jul 17. Link to article on publisher's site
Goertz, Lukas; Tsiamas, Panagiotis; Karellas, Andrew; Sajo, Erno; and Zygmanski, Piotr, "Monte Carlo simulation of a prototypical patient dosimetry system for fluoroscopic procedures" (2015). Radiology Publications and Presentations. 239.