The use of a thyroid shield for intra-oral anterior oblique occlusal views - a risk based approach

Mark Worrall, Alison Menhinick, Donald J. Thomson

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)
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Objectives: To estimate the radiation dose reduction to the thyroid for an anterior oblique occlusal view from the use of a thyroid shield, compare this with the variation in thyroid dose resulting from differences in examination positioning and discuss the additional considerations associated with the use of a thyroid shield before making a recommendation on their routine use for this examination. Methods: Doses to the oral mucosa, the salivary glands, the thyroid, the extrathoracic airways, the oesophagus and the lungs were directly measured for anterior oblique occlusal X-rays of a Rando phantom with and without a thyroid shield using strips of calibrated XRQA Gafchromic film. The examination was also simulated using Monte Carlo software for the without thyroid shield case for a comparison of the dose and to evaluate the dosimetric effect of suboptimal examination positioning.Results: A 36% reduction in thyroid dose was measured as a result of thyroid shield use; the effective dose reduction is of the order of 22%. Suboptimal positioning was found to increase thyroid dose by a far more significant amount. Conclusions: Despite the reduction in thyroid dose, cost-benefit considerations mean that the purchase of a thyroid shield is only recommended where a very high number of anterior oblique occlusal views are undertaken. Optimization efforts for this examination are better focussed on training in examination positioning.

Original languageEnglish
Article number20170140
Pages (from-to)1-11
Number of pages11
JournalDentomaxillofacial Radiology
Issue number1
Early online date27 Oct 2017
Publication statusPublished - 2018


  • Radiography
  • thyroid gland
  • Thyroid gland
  • Diagnostic Imaging
  • Humans
  • Radiation Protection/instrumentation
  • Software
  • Thyroid Gland/radiation effects
  • Radiation Dosage
  • Phantoms, Imaging
  • Monte Carlo Method

ASJC Scopus subject areas

  • General Dentistry
  • Radiology Nuclear Medicine and imaging
  • Otorhinolaryngology


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