European Radiology

, Volume 18, Issue 4, pp 759–772 | Cite as

Validation of a Monte Carlo tool for patient-specific dose simulations in multi-slice computed tomography

  • Paul Deak
  • Marcel van Straten
  • Paul C. Shrimpton
  • Maria Zankl
  • Willi A. Kalender
Computer Tomography

Abstract

Estimating the dose delivered to the patient in X-ray computed tomography (CT) examinations is not a trivial task. Monte Carlo (MC) methods appear to be the method of choice to assess the 3D dose distribution. The purpose of this work was to extend an existing MC-based tool to account for arbitrary scanners and scan protocols such as multi-slice CT (MSCT) scanners and to validate the tool in homogeneous and heterogeneous phantoms. The tool was validated by measurements on MSCT scanners for different scan protocols under known conditions. Quantitative CT Dose Index (CTDI) measurements were performed in cylindrical CTDI phantoms and in anthropomorphic thorax phantoms of various sizes; dose profiles were measured with thermoluminescent dosimeters (TLD) in the CTDI phantoms and compared with the computed dose profiles. The in-plane dose distributions were simulated and compared with TLD measurements in an Alderson-Rando phantom. The calculated dose values were generally within 10% of measurements for all phantoms and all investigated conditions. Three-dimensional dose distributions can be accurately calculated with the MC tool for arbitrary scanners and protocols including tube current modulation schemes. The use of the tool has meanwhile also been extended to further scanners and to flat-detector CT.

Keywords

Monte Carlo Dose CT 

Notes

Acknowledgements

We gratefully acknowledge the help of Oliver Langner and Rosi Banckwitz in relation to dose measurements and TLD reading procedures. This work was financially supported partially by grant AZ 460/01 MEDBILD, Bavarian Research Foundation, Munich, Germany, and partially by the EC-EURATOM 6 Framework Programme (2002–2006) as part of the “Safety and Efficacy of Computed Tomography (CT): a Broad Perspective” project (contract FP/002388). We are grateful to the colleagues at Siemens Medical Solutions who provided the tube current curve information to us for the TCM evaluation.

References

  1. 1.
    Mettler FA, Wiest PW, Locken JA, Kelsey CA (2000) CT scanning: patterns of use and dose. J Radiol Prot 20:353–359PubMedCrossRefGoogle Scholar
  2. 2.
    Shrimpton PC, Edyvean S (1998) CT scanner dosimetry. Br J Radiol 71:1–3PubMedGoogle Scholar
  3. 3.
    BfS (2003) Jahresbericht 2003. Annual rep., Bundesamt für Strahlenschutz, SalzgitterGoogle Scholar
  4. 4.
    Brix G, Nagel HD, Stamm G, Veit R, Lechel U, Griebel J, Galanski M (2003) Radiation exposure in multi-slice versus single-slice spiral CT: results of a nationwide survey. Eur Radiol 13:1979–1991. DOI 10.1007/s00330-003-1883-y PubMedCrossRefGoogle Scholar
  5. 5.
    Andreo P (1991) Monte Carlo techniques in medical radiation physics. Phys Med Biol 36:861–920PubMedCrossRefGoogle Scholar
  6. 6.
    Geant4 Collaboration (2007) Introduction to Geant4. http://geant4.web.cern.ch/geant4/
  7. 7.
    Team XMC (2003) MCNP-a general Monte Carlo N-particle transport code, version 5. LA-UR-03-1987 RSICC, Los Alamos, USAGoogle Scholar
  8. 8.
    Nelson WR, Hirayama H, Rogers DOW (1985) The EGS4 code system. Stanford Linear Accelerator Center, Stanford University, USAGoogle Scholar
  9. 9.
    Zankl M, Panzer W, Drexler G (1991) The calculation of the dose from external photon exposures using reference human phantoms and Monte Carlo methods. Part VI: organ doses from computed tomography examinations. Report 31, GSF, NeuherbergGoogle Scholar
  10. 10.
    Schmidt B, Kalender WA (2002) A fast voxel-based Monte Carlo method for scanner- and patient-specific dose calculations in computed tomography. Physica Medica XVIII:43–53Google Scholar
  11. 11.
    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 48:2645–2663PubMedCrossRefGoogle Scholar
  12. 12.
    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 PubMedCrossRefGoogle Scholar
  13. 13.
    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 PubMedCrossRefGoogle Scholar
  14. 14.
    Schneider U, Pedroni E, Lomax A (1996) The calibration of CT Hounsfield units for radiotherapy treatment planning. Phys Med Biol 41:111–124PubMedCrossRefGoogle Scholar
  15. 15.
    Tucker DM, Barnes GT, Chakraborty DP (1991) Semiempirical model for generating tungsten target X-ray spectra. Med Phys 18:211–218PubMedCrossRefGoogle Scholar
  16. 16.
    Boone JM, Seibert A (1997) An accurate method for computer-generating tungsten anode X-ray spectra from 30 to 140 kV. Med Phys 24:1661–1670PubMedCrossRefGoogle Scholar
  17. 17.
    Aichinger H, Dierker J, Joite-Barfuß S, Säbel M (2003) Radiation exposure and image quality in X-ray diagnostic radiology. Physical principles and clinical applications. Springer, BerlinGoogle Scholar
  18. 18.
    Cullen DE, Hubbell JH, Kissel L (1997) EPDL 97: The Evaluated Photon Data Library, 97 Version. UCRL-50400 6. Lawrence Livermore National Laboratory, LivermoreGoogle Scholar
  19. 19.
    Chao TC, Bozkurt A, Xu GX (2001) Conversion coefficients based on the VIP-Man anatomical model and EGS4-VLSI code for external monoenergetic photons from 10 kV to 10 MV. Health Phys 81:163–183PubMedCrossRefGoogle Scholar
  20. 20.
    Born M (1969) Atomic physics. Blackie and Son Ltd, LondonGoogle Scholar
  21. 21.
    Schardt P, Deuringer J, Freudenberger J, Hell E, Knüpfer W, Mattern D, Schild M (2004) New X-ray tube performance in computed tomography by introducing the rotating envelope tube technology. Med Phys 31:2699–2706. DOI 10.1118/1.1783552 PubMedCrossRefGoogle Scholar
  22. 22.
    Kalender WA (2005) Computed tomography, 2nd edn. Publicis Corporate Publishing, ErlangenGoogle Scholar
  23. 23.
    Kalender WA, Wolf H, Suess C, Gies M, Greess H, Bautz WA (1999) Dose reduction in CT by on-line tube current control: principles and validation on phantoms and cadavers. Eur Radiol 9:323–328. DOI 10.1007/s003300050674 PubMedCrossRefGoogle Scholar
  24. 24.
    Flohr T, McCollough CH, Bruder H, Petersilka M, Gruber K, Suess C, Grasruck M, Stierstorfer K, Krauss B, Raupach R, Primak A, Küttner A, Achenbach S, Becker C, Kopp A, Ohnesorge B (2006) First performance evaluation of a dual-source CT (DSCT) system. Eur Radiol 16:256–268. DOI 10.1007/s00330-005-2919-2 PubMedCrossRefGoogle Scholar
  25. 25.
    Riedel T (2005) Deterministic simulation of arbitrary CT measurements with experimental verification. In: Kalender WA (ed) Berichte aus dem Institut für Medizinische Physik, vol 14. Shaker Verlag, AachenGoogle Scholar
  26. 26.
    Ulzheimer S, Kalender WA (2003) Assessment of calcium scoring performance in cardiac computed tomography. Eur Radiol 13:484–497. DOI 10.1007/s00330-002-1746-y PubMedGoogle Scholar
  27. 27.
    Archer BR, Glaze S, North LB, Bushong SC (1977) Dosimeter placement in the Rando phantom. Med Phys 4:315–318PubMedCrossRefGoogle Scholar
  28. 28.
    European Commision (2000) Recommendations for patient dosimetry in diagnostic radiology using TLD. Report EUR 19604 EN, LuxembourgGoogle Scholar
  29. 29.
    Tzedakis A, Damilakis J, Perisinakis K, Stratakis J, Gourtsoyiannis N (2006) The effect of z overscanning on patient effective dose from multidetector helical computed tomography. Med Phys 32:1621–1629CrossRefGoogle Scholar
  30. 30.
    Petoussi-Henss N, Zankl M, Fill U, Regulla D (2002) The GSF family of voxel phantoms. Phys Med Biol 47:89–106PubMedCrossRefGoogle Scholar
  31. 31.
    Zankl M, Fill U, Petoussi-Henss N, Regulla D (2002) Organ dose conversion coefficients for external photon irradiation of male and female voxel models. Phys Med Biol 47:2367–2385CrossRefGoogle Scholar
  32. 32.
    Kalender WA, Kyriakou Y (2007) Flat-detector computed tomography (FD-CT). Eur Radiol 17:2767–2779. DOI 10.1007/s00330-007-0651-9 PubMedCrossRefGoogle Scholar
  33. 33.
    Kachelrieß M, Knaup M, Bockenbach O (2007) Hyperfast parallel-beam and cone-beam backprojection using the cell general purpose hardware. Med Phys 34:1474–1486. DOI 10.1118/1.2710328 PubMedCrossRefGoogle Scholar

Copyright information

© European Society of Radiology 2007

Authors and Affiliations

  • Paul Deak
    • 1
  • Marcel van Straten
    • 1
  • Paul C. Shrimpton
    • 2
  • Maria Zankl
    • 3
  • Willi A. Kalender
    • 1
  1. 1.Institute of Medical PhysicsUniversity Erlangen-NürnbergErlangenGermany
  2. 2.Health Protection AgencyChiltonUK
  3. 3.GSF - National Research Center for Environment and HealthNeuherbergGermany

Personalised recommendations