Abstract
The Monte Carlo (MC) method is a powerful tool to examine the impact of different CT scan-parameters, protocols and individual anatomy on patient dose. General information about dose exposition required by radiation protection legislation for CT examination is mostly based on measurements or generalized MC simulations with humanoid phantoms. This is an approximation to the actual patient anatomy and must be considered as an estimation of the actually applied dose. In special cases, such as the abdominal CT of a pregnant woman, an exact and individual dose calculation could improve the information required for decisions regarding the need for subsequent abortion.
MC simulations are time consuming and the handling of available MC packages requires a skilled user. We introduce a free software tool GMctdospp which serves as a front-end and user-code for the general purpose MC-package EGSnrc. All scan parameters needed for a simulation of the CT-examination can be intuitively defined in the graphical user interface. The graphical representation and analysis of resulting dose distributions by means of profiles and dose volume histograms is included in the front-end. Further, the complete controlling of a distributed computing environment is performed by GMctdospp, allowing an arbitrary number of conventional desktop PCs to be used for calculation. CT data sets can be loaded in the medical imaging standard DICOM-format. Regions of interest (ROIs) can be defined as DICOMRT struct and evaluated statistically as mean dose or dose volume histogram. The required conversion of CT units (Hounsfield) to mass densities and materials needed for the MC simulation can be defined (defaults are set). Calculating absolute dose distributions is possible with the use of a calibration run, where dose in an ionisation chamber is once measured and then calculated for identical beam source parameters (energy spectrum, filtration, slice thickness etc.).
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References
Shrimpton PC, Edyvean S (1998) CT scanner dosimetry. Br J Radiol 71:1–3
ImPACT at http://www.impactscan.org
Impactdose at http://www.vamp-gmbh.de/software/impactdose.php
CT-Expo at http://www99.mh-hannover.de/kliniken/radiologie/str_04.html#ctgraphie
Jarry G, DeMarco JJ, Beifuss U, Cagnon CH, McNitt-Gray MF (2003) A Monte Carlo-based method to estimate radiation dose from spiral CT: from phantom testing to patient specific models. Phys Med Biol 48:2645–2663
DeMarco JJ, Cagnon CH, Cody DD, Stevens DM, McCollough CH, O’Daniel J, McNitt-Gray MF (2005) A Monte Carlo based method to estimate radiation dose from multidetector CT (MDCT): cylindrical and anthropomorphic phantoms. Phys Med Biol 50:3989–4004. DOI 10.1088/0031-9155/50/17/005
Theocharopoulos N, Damilakis J, Perisinakis K, Tzedakis A, Karantanas A, Gourtsoyiannis N (2006) Estimation of effective doses to adult and pediatric patients from multislice computed tomography: a method based on energy imparted. Med Phys 33:3846–3856. DOI 10.1118/1.2349694
Deak P, Van Straten M, Shrimpton PC, Zankl M, Kalender WA (2007) Validation of a Monte Carlo tool for patient-specific dose simulations in multi-slice computed tomography. Eur Radiol 18: 759–772 DOI 10.1007/s00330-007-0815-7
Ay M, Zaidi H (2005) Development and validation of MCNP4C based Monte Carlo simulator for fan-and cone-beam X-ray CT. Phys Med Biol 50:4863–4885
Kawrakow I, Rogers DWO (2006) The EGSnrc Code System: Monte Carlo Simulation of Electron and Photon Transport; NRCC Report No. PIRS-701, National Research Council of Canada
Wulff J, Keil B, Auvanis D,. Heverhagen JT, Klose KJ, Zink K (2007) Dosimetrische Evaluation von Augenlinsen-Protektoren in der Cmputertomographie — Messungen und Monte-Carlo-Simulationen. Z Med Phys 18:9–26
Dicom at http://medical.nema.org/
Williamson JF (1987) Monte Carlo evaluation of kerma at a point for photon transport problems.;ed Phys 14:567–576
CONDOR at http://www.cs.wisc.edu/condor
DIN EN 61223-2-6 (IEC 61223-2-6) Bewertung und routinemäßige Prüfung in Abteilungen für medizinische Bildgebung Teil 2-6 Kontanzprüfungen — Röntgeneinrichtungen für die Computertomographie
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© 2009 Springer-Verlag Berlin Heidelberg
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Schmidt, R. et al. (2009). Monte Carlo based calculation of patient exposure in X-ray CT-examinations. In: Vander Sloten, J., Verdonck, P., Nyssen, M., Haueisen, J. (eds) 4th European Conference of the International Federation for Medical and Biological Engineering. IFMBE Proceedings, vol 22. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-89208-3_596
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DOI: https://doi.org/10.1007/978-3-540-89208-3_596
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-89207-6
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