Skip to main content
SpringerLink
Log in

Eye-lens bismuth shielding in paediatric head CT: artefact evaluation and reduction

  • Original Article
  • Published:
Pediatric Radiology Aims and scope Submit manuscript

Abstract

Background

CT scans of the brain, sinuses and petrous bones performed as the initial imaging test for a variety of indications have the potential to expose the eye-lens, considered among the most radiosensitive human tissues, to a radiation dose. There are several studies in adults discussing the reduction of orbital dose resulting from the use of commercially available bismuth-impregnated latex shields during CT examinations of the head.

Objective

To evaluate bismuth shielding-induced artefacts and to provide suggestions for optimal eye-lens shielding in paediatric head CT.

Materials and methods

A bismuth shield was placed over the eyelids of 60 consecutive children undergoing head CT. Images were assessed for the presence and severity of artefacts with regard to eye-shield distance and shield wrinkling. An anthropomorphic paediatric phantom and thermoluminescence dosimeters (TLDs) were used to study the effect of eye lens-to-shield distance on shielding efficiency.

Results

Shields were tolerated by 56/60 children. Artefacts were absent in 45% of scans. Artefacts on orbits, not affecting and affecting orbit evaluation were noted in 39% and 14% of scans, respectively. Diagnostically insignificant artefacts on intracranial structures were noted in 1 case (2%) with shield misplacement. Mean eye-lens-to-shield distance was 8.8 mm in scans without artefacts, and 4.3 mm and 2.2 mm in scans with unimportant and diagnostically important artefacts, respectively. Artefacts occurred in 8 out of 9 cases with shield wrinkling. Dose reduction remained unchanged for different shield-to-eye distances.

Conclusion

Bismuth shielding-related artefacts occurring in paediatric head CT are frequent, superficial and diagnostically insignificant when brain pathology is assessed. Shields should be placed 1 cm above the eyes when orbital pathology is addressed. Shield wrinkling should be avoided.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7

Similar content being viewed by others

References

  1. Brenner D, Elliston C, Hall E et al (2001) Estimated risks of radiation-induced fatal cancer from pediatric CT. AJR 176:289–296

    CAS  PubMed  Google Scholar 

  2. International Commission on Radiological Protection (1990) Recommendations of the international commission on radiological protection. In: ICRP Publication 60. Ann ICRP 21:1–3, Pergamon, Oxford

  3. National Research Council (1990) Health effects exposure to low levels of ionizing radiation, BEIR V. National Academy, Washington

    Google Scholar 

  4. Merriam GR Jr, Focht EF (1957) A clinical study of radiation cataracts and the relationship to dose. Am J Roentgenol Radium Ther Nucl Med 77:759–785

    PubMed  Google Scholar 

  5. Minamoto A, Taniguchi H, Yoshitani N et al (2004) Cataracts in atomic bomb survivors. Int J Radiat Biol 80:339–345

    Article  CAS  PubMed  Google Scholar 

  6. Hall P, Granath F, Lundell M et al (1999) Lenticular opacities in individuals exposed to ionizing radiation in infancy. Radiat Res 152:190–195

    Article  CAS  PubMed  Google Scholar 

  7. McLaughlin DJ, Mooney RB (2004) Dose reduction to radiosensitive tissues in CT. Do commercially available shields meet the users’ needs? Clin Radiol 59:446–450

    Article  CAS  PubMed  Google Scholar 

  8. Hopper KD, Neuman JD, King SH et al (2001) Radioprotection to the eye during CT scanning. AJNR 22:1194–1198

    CAS  PubMed  Google Scholar 

  9. Colombo P, Pedroli G, Nicoloso M et al (2004) Evaluation of the efficacy of a bismuth shield during CT examinations. Radiol Med 108:560–568

    PubMed  Google Scholar 

  10. Keil B, Wulff J, Schmitt R et al (2008) Protection of eye lens in computed tomography—dose evaluation on an anthropomorphic phantom using thermo-luminescent dosimeters and Monte-Carlo simulations. Rofo 180:1047–1053

    CAS  PubMed  Google Scholar 

  11. Kim S, Yoshizumi TT, Frush DP et al (2009) Dosimetric characterization of bismuth shields in CT: measurements and Monte Carlo simulations. Radiat Prot Dosim 133:105–110

    Article  CAS  Google Scholar 

  12. Hein E, Rogalla P, Klingebiel R et al (2002) Low-dose CT of the paranasal sinuses with eye lens protection: effect on image quality and radiation dose. Eur Radiol 12:1693–1696

    Article  PubMed  Google Scholar 

  13. Perisinakis K, Raissaki M, Theocharopoulos N et al (2005) Reduction of eye lens radiation dose by orbital bismuth shielding in pediatric patients undergoing CT of the head: a Monte Carlo study. Med Phys 32:1024–1030

    Article  PubMed  Google Scholar 

  14. Mukundan S Jr, Wang PI, Frush DP et al (2007) MOSFET dosimetry for radiation dose assessment of bismuth shielding of the eye in children. AJR 188:1648–1650

    Article  PubMed  Google Scholar 

  15. Hopper KD (2002) Orbital, thyroid and breast superficial radiation shielding for patients undergoing diagnostic CT. Semin Ultrasound CT MR 23:423–427

    Article  PubMed  Google Scholar 

  16. Geleijns J, Salvadó Artells M, Veldkamp WJ et al (2006) Quantitative assessment of selective in-plane shielding of tissues in computed tomography through evaluation of absorbed dose and image quality. Eur Radiol 16:2334–2340

    Article  CAS  PubMed  Google Scholar 

  17. Shah R, Gupta AK, Rehani MM et al (2005) Effect of reduction in tube current on reader confidence in paediatric computed tomography. Clin Radiol 60:224–231

    Article  CAS  PubMed  Google Scholar 

  18. Fricke BL, Donnelly LF, Frush DP et al (2003) In-plane bismuth breast shields for pediatric CT: effects on radiation dose and image quality using experimental and clinical data. AJR 180:407–411

    PubMed  Google Scholar 

  19. Hohl C, Wildberger JE, Süss C et al (2006) Radiation dose reduction to breast and thyroid during MDCT: effectiveness of an in-plane bismuth shield. Acta Radiol 47:562–567

    Article  CAS  PubMed  Google Scholar 

  20. Yeoman LJ, Howarth L, Britten A et al (1992) Gantry angulation in brain CT: dosage implications, effect on posterior fossa artifacts, and current international practice. Radiology 184:113–116

    CAS  PubMed  Google Scholar 

  21. Heaney DE, Norvill CA (2006) A comparison of reduction in CT dose through the use of gantry angulations or bismuth shields. Australas Phys Eng Sci Med 29:172–178

    Article  CAS  PubMed  Google Scholar 

  22. Tzedakis A, Damilakis J, Perisinakis K et al (2005) The effect of z overscanning on patient effective dose from multidetector helical computed tomography examinations. Med Phys 32:1621–1629

    Article  CAS  PubMed  Google Scholar 

  23. Leswick DA, Hunt MM, Webster ST et al (2008) Thyroid shields versus z-axis automatic tube current modulation for dose reduction at neck CT. Radiology 249:572–580

    Article  PubMed  Google Scholar 

  24. Smith AB, Dillon WP, Lau BC et al (2008) Radiation dose reduction strategy for CT protocols: successful implementation in neuroradiology section. Radiology 247:499–506

    Article  PubMed  Google Scholar 

  25. Papadakis AE, Perisinakis K, Damilakis J (2007) Angular on-line tube current modulation in multidetector CT examinations of children and adults: the influence of different scanning parameters on dose reduction. Med Phys 34:2864–2874

    Article  PubMed  Google Scholar 

  26. Papadakis AE, Perisinakis K, Damilakis J (2008) Automatic exposure control in pediatric and adult multidetector CT examinations: a phantom study on dose reduction and image quality. Med Phys 35:4567–4576

    Article  PubMed  Google Scholar 

  27. Coursey C, Frush DP, Yoshizumi T et al (2008) Pediatric chest MDCT using tube current modulation: effect on radiation dose with breast shielding. AJR 190:W54–W61

    Article  PubMed  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Radiology, University Hospital of Heraklion, University of Crete, Faculty of Medicine, Stavrakia, Voutes, PO Box 2208, 71003, Heraklion, Crete, Greece

    Maria Raissaki & Kostas Perisinakis

  2. Medical Physics Department, University of Crete, Faculty of Medicine, Heraklion, Crete, Greece

    John Damilakis & Nicholas Gourtsoyiannis

Authors
  1. Maria Raissaki
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Kostas Perisinakis
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. John Damilakis
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Nicholas Gourtsoyiannis
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Maria Raissaki.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Raissaki, M., Perisinakis, K., Damilakis, J. et al. Eye-lens bismuth shielding in paediatric head CT: artefact evaluation and reduction. Pediatr Radiol 40, 1748–1754 (2010). https://doi.org/10.1007/s00247-010-1715-6

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00247-010-1715-6

Keywords

Search

Navigation