A Monte Carlo based method to estimate radiation dose from multidetector CT (MDCT): cylindrical and anthropomorphic phantoms

摘要: The purpose of this work was to extend the verification Monte Carlo based methods for estimating radiation dose in computed tomography (CT) exams beyond a single CT scanner multidetector (MDCT) scanner, and from cylindrical CTDI phantom measurements both physical anthropomorphic phantoms. Both phantoms were scanned on an MDCT under specified conditions. A pencil ionization chamber used record exposure phantom, while MOSFET (metal oxide semiconductor field effect transistor) detectors at surface phantom. Reference made air isocentre using Detailed models developed describe x-ray source (spectra, bowtie filter, etc) geometry factors (distance focal spot isocentre, movement due axial or helical scanning, etc). Models (CTDI) available previous work. For image data create detailed voxelized model phantom's geometry. Anthropomorphic material compositions provided by manufacturer. simulation scan performed mathematical parameters. Tallies recorded specific voxel locations corresponding measurements. Simulations scans obtain normalization convert results absolute values. body (32 cm) agreed within 3.5% across all measured values contiguous showed significant variation ranged 8 mGy/100 mAs 16 mAs. Results overlapping pitch (0.9375) extended (1.375) also obtained. Comparisons between value derived simulations demonstrate agreement terms as well spatially varying characteristics. This demonstrates ability detector Future will be patient different sizes other scanners.