title: Effectiveness of thyroid gland shielding in dental CBCT using a paediatric anthropomorphic phantom.
abstract: OBJECTIVE
  The purpose of the study is to evaluate the effectiveness of thyroid shielding in dental CBCT examinations using a paediatric anthropomorphic phantom.
  
  
  METHODS
  An ATOM(®) 706-C anthropomorphic phantom (Computerized Imaging Reference Systems Inc., Norfolk, VA) representing a 10-year-old child was loaded with six thermoluminescent dosemeters positioned at the level of the thyroid gland. Absorbed doses to the thyroid were measured for five commercially available thyroid shields using a large field of view (FOV).
  
  
  RESULTS
  A statistically significant thyroid gland dose reduction was found using thyroid shielding for paediatric CBCT examinations for a large FOV. In addition, a statistically significant difference in thyroid gland doses was found depending on the position of the thyroid gland. There was little difference in the effectiveness of thyroid shielding when using a lead vs a lead-equivalent thyroid shield. Similar dose reduction was found using 0.25- and 0.50-mm lead-equivalent thyroid shields.
  
  
  CONCLUSIONS
  Thyroid shields are to be recommended when undertaking large FOV CBCT examinations on young patients.
authors.affiliation: 1 School of Dentistry, University of Manchester, Manchester, UK.
authors.forename: A
authors.initials: A
authors.lastname: Hidalgo
authors.forename: J
authors.initials: J
authors.lastname: Davies
authors.forename: K
authors.initials: K
authors.lastname: Horner
authors.forename: C
authors.initials: C
authors.lastname: Theodorakou
mesh_terms: D002648:Child; D054893:Cone-Beam Computed Tomography; D006801:Humans; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011835:Radiation Protection / Q000295:instrumentation*; D013819:Thermoluminescent Dosimetry; D013961:Thyroid Gland / Q000528:radiation effects*
keywords: cone beam computed tomography; thermoluminescent dosimetry; thyroid gland