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European Radiology

, Volume 14, Issue 7, pp 1275–1284 | Cite as

Assessment of a theoretical formalism for dose estimation in CT: an anthropomorphic phantom study

  • G. Brix
  • U. Lechel
  • R. Veit
  • R. Truckenbrodt
  • G. Stamm
  • E. M. Coppenrath
  • J. Griebel
  • H.-D. Nagel
Physics

Abstract

Dose assessment in computed tomography (CT) is challenging due to the vast variety of CT scanners and imaging protocols in use. In the present study, the accurateness of a theoretical formalism implemented in the PC program CT-EXPO for dose calculation was evaluated by means of phantom measurements. Phantom measurements were performed with four 1-slice, four 4-slice and two 16-slice spiral CT scanners. Firstly, scanner-specific n CTDIw values were measured and compared with the corresponding standard values used for dose calculation. Secondly, effective doses were determined for three CT scans (head, chest and pelvis) performed at each of the ten installations from readings of thermoluminescent dosimeters distributed inside an anthropomorphic Alderson phantom and compared with the corresponding dose values computed with CT-EXPO. Differences between standard and individually measured n CTDIw values were less than 16%. Statistical analysis yielded a highly significant correlation (P<0.001) between calculated and measured effective doses. The systematic and random uncertainty of the dose values calculated using standard n CTDIw values was about −9 and ±11%, respectively. The phantom measurements and model calculations were carried out for a variety of CT scanners and representative scan protocols validate the reliability of the dosimetric formalism considered—at least for patients with a standard body size and a tube voltage of 120 kV selected for the majority of CT scans performed in our study.

Keywords

Computed tomography Patient exposure Dosimetry Anthropomorphic phantom Scanner matching 

Notes

Acknowledgements

The authors would like to thank the owners and the staff of the ten facilities where the phantom measurements were performed for their excellent collaboration. Furthermore, the support of R. Banckwitz and C. Süß (Siemens AG, Medical Solutions, Forchheim, Germany) is gratefully acknowledged.

References

  1. 1.
    Kalender WA, Seissler W, Klotz E, Vock O (1990) Spiral volumetric CT with single-breath-hold technique, continuous transport, and scanner rotation. Radiology 176:181–183PubMedGoogle Scholar
  2. 2.
    Berland LL, Smith JK (1998) Multidetector-array CT: once again, technology creates new opportunities. Radiology 209:327–329PubMedGoogle Scholar
  3. 3.
    Klingenbeck-Regn K, Schaller S, Flohr T, Ohnesorge B, Kopp AF, Baum U (1999) Subsecond multi-slice computed tomography: basics and applications. Eur J Radiol 31:110–124PubMedGoogle Scholar
  4. 4.
    Rydberg J, Buckalter KA, Caldemeyer KS, Phillips MD, Conces DJ, Aisen AM, Persohn SA, Kopecky KK (2000) Multisection CT: scanning techniques and clinical applications. Radiographics 20:1787–1806PubMedGoogle Scholar
  5. 5.
    Dawson P, Lees WR (2001) Multi-slice technology in computed tomography. Clin Radiol 56:302–309PubMedGoogle Scholar
  6. 6.
    Laghi A, Lannaccone R, Panebianco V, Carbone L, Passariello R (2001) Multislice CT colonography: technical developments. Semin Ultrasound CT MR 22:425–431PubMedGoogle Scholar
  7. 7.
    Schoepf UJ, Becker CR, Hofmann LK, Das M, Flohr T, Ohnesorg BM, Baumert B, Rolnick J, Alles JM, Raptopulos V (2003) Multislice CT angiography. Eur Radiol 13:1946–1961PubMedGoogle Scholar
  8. 8.
    Hong C, Becker CR, Schoepf UJ, Ohnesorge B, Bruening R, Reiser MF (2002) Coronary artery calcium: absolute quantification in nonenhanced and contrast-enhanced multi-detector row CT studies. Radiology 223:474–480PubMedGoogle Scholar
  9. 9.
    UNSCEAR 2000 Report, vol. I, sources and effects of ionizing radiation. Annex D: medical radiation exposures (2000). United Nations Sales PublicationsGoogle Scholar
  10. 10.
    LeHeron JC (1993) CTDOSE—a computer program to enable the calculation of organ doses and dose indices for CT examinations. Ministry of Health, National Radiation Laboratory, Christchurch, New ZealandGoogle Scholar
  11. 11.
    Imaging Performance Assessment of CT-Scanners Group. ImPACT CT Patient Dosimetry Calculator v. 0.99 j. London: ImPACT. http://www.impactscan.org
  12. 12.
    Kalender WA, Schmidt B, Zankl M, Schmidt M (1999) A PC program for estimating organ dose and effective dose values in computed tomography. Eur Radiol 9:555–562PubMedGoogle Scholar
  13. 13.
    National Institute of Radiation Hygiene (1999) CT dose calculation software “CT-Dose”. National Institute of Radiation Hygiene, Herlev. ctdose@sis.dkGoogle Scholar
  14. 14.
    Tack D (2001) Comments on Kalender et al.: a PC program for estimating organ dose and effective dose values in computed tomography. Eur Radiol 11:2641–2642 and Kalender WA, Schmidt B (2001) Reply to Tack D: a PC program for estimating organ dose and effective dose values in computed tomography. Eur Radiol 11:2643CrossRefGoogle Scholar
  15. 15.
    Stamm G, Nagel HD (2002) CT-Expo-ein neuartiges Programm zur Dosisevaluierung in der CT. Fortschr Rontgenstr 174:1570–1576Google Scholar
  16. 16.
    Jones DG, Shrimpton PC (1991) Survey of CT practice in the UK. Part 3. Normalised organ doses calculated using Monte Carlo techniques. NRPB-250. National Radiological Protection Board, OxonGoogle Scholar
  17. 17.
    Zankl M, Panzer W, Drexler G (1991) The calculation of dose from external photon exposures using reference human phantoms and Monte Carlo methods. Part IV. Organ doses from tomographic examinations. GSF report 30/91. NeuherbergGoogle Scholar
  18. 18.
    Galanski M, Nagel HD, Stamm G (2001) CT-Expositionspraxis in der Bundesrepublik Deutschland. Fortschr Rontgenstr 173:R1–R66Google Scholar
  19. 19.
    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 13:1979–1991CrossRefPubMedGoogle Scholar
  20. 20.
    Nagel HD, Galanski M, Hidajat N, Maier W, Schmidt T (2002) Radiation exposure in computed tomography–fundamentals, influencing parameters, dose assessment, optimisation, scanner data, terminology. 4th edn. CTB Publications, Hamburg (ctb-publications@gmx.de)Google Scholar
  21. 21.
    ICRP Publication 60 (1991) 1990 recommendations of the International Commission on Radiological Protection. Annals of the ICRP vol 21/1-3. Elsevier Science, OxfordGoogle Scholar
  22. 22.
    European Commission (1999) Report EUR 16262 EN “European guidelines on quality criteria for computed tomography”Google Scholar
  23. 23.
    Kramer R, Zankl M, Wiliams G, Drexler G (1982) The calculation of dose from external photon exposures using reference human phantoms and Monte Carlo methods. Part I. The male (Adam) and female (Eva) adult mathematical phantoms. GSF report S-885. NeuherbergGoogle Scholar
  24. 24.
    Shrimpton PC, Jones DG, Hillier MC, Wall BF, Leheron JC, Faulkner K (1991) Survey of CT practice in the UK. Part 2. Dosimetric aspects. NRPB-249. London: HMSO, 48Google Scholar
  25. 25.
    Taylor JR (1997) An introduction to error analysis: The study of uncertainties in physical measurements. 2nd edn. University Science Books, Sausalito, CAGoogle Scholar
  26. 26.
    ICRU Publication 17 (1970) Radiation dosimetry: X-rays generated at potentials of 5 to 150 kV. ICRU Publications, Washington, DCGoogle Scholar
  27. 27.
    European Commission (2000) Report EUR 19604 EN “Recommendations for patient dosimetry in diagnostic radiology using TLD”Google Scholar
  28. 28.
    Jastrow W Atlas of human sections in the internet. Labelling of sections from the visible human project. http://www.uni-mainz.de/FB/medizin/anatomie/workshop/engl/welcome.html
  29. 29.
    Huda W, Sandison GA (1984) Estimation of mean organ doses in diagnostic radiology from Rando phantom measurements. Health Phys 47:463–467PubMedGoogle Scholar
  30. 30.
    Shrimpton PC, Edyvean S (1998) CT scaner dosimetry. Br J Radiol 71:1–3Google Scholar
  31. 31.
    Cohnen M, Poll LW, Puettmann C, Ewen K, Saleh A, Mödder U (2003) Effective doses in standard protocols for multi-slice CT scanning. Eur Radiol 13:1148–1153PubMedGoogle Scholar
  32. 32.
    Petoussi-Henss N, Zankl M, Fill U, Regulla D (2002) The GSF family of voxel phantoms. Phys Med Biol 47:89–106CrossRefPubMedGoogle Scholar
  33. 33.
    Dinkel HP, Sonnenschein M, Hoppe H, Vock P (2003) Low-dose multislice CT of the thorax in follow-up of malignant lymphoma and extrapulmonary primary tumors. Eur Radiol 13:1241–1249PubMedGoogle Scholar
  34. 34.
    Iannaccone R, Laghi A, Catalano C, Mangiapane F, Piacentini F, Passariello R (2003) Feasibility of ultra-low-dose multislice CT colonography for the detection of colorectal lesions: preliminary experience. Eur Radiol 13:1297–1313PubMedGoogle Scholar
  35. 35.
    Diederich S (2003) Radiation dose in helical CT for detection of pulmonary embolism. Eur Radiol 13:1491–1493CrossRefPubMedGoogle Scholar
  36. 36.
    Jakobs TF, Wintersperger BJ, Herzog P, Flohr T, Suess C, Knez A, Reiser MF, Becker CR (2003) Ulta-low-dose coronary artery calcium screening using mutlislice CT with retrospective ECG gating. Eur Radiol 13:1923–1930CrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • G. Brix
    • 1
  • U. Lechel
    • 1
  • R. Veit
    • 1
  • R. Truckenbrodt
    • 1
  • G. Stamm
    • 2
  • E. M. Coppenrath
    • 3
  • J. Griebel
    • 1
  • H.-D. Nagel
    • 4
  1. 1.Department of Radiation Protection and Health, Division of Medical Radiation Hygiene and DosimetryFederal Office for Radiation ProtectionNeuherbergGermany
  2. 2.Department of RadiologyHannover Medical SchoolHannoverGermany
  3. 3.Department of RadiologyUniversity of MunichMunichGermany
  4. 4.Department of Science and TechnologyPhilips Medical SystemsHamburgGermany

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