[The Use of a Thyroid Collar for Intraoral Radiography]

Objective: To determine whether a thyroid collar is a reasonable measure to reduce patient exposure from intraoral radiography (cost benefit analysis).

Design: In the thyroid gland of a Rando phantom dose measurements were carried out to determine the effect of a thyroid collar during intraoral radiography.

Setting: Department of Oral Radiology at ACTA, Amsterdam.

Methods: Dose measurements were carried out using LTDs. The average absorbed dose to the thyroid gland with and without thyroid collar from intraoral radiography was compared using an analysis of variance.

Results: For periapical radiographs the equivalent dose to the thyroid gland was significantly lower (p < 0.05) when a thyroid collar was used. For bitewing radiography there were no significant effects of the thyroid collar (p > 0.05). The cost benefit analysis showed that it takes more than 40 years before the benefits of a thyroid collar exceed the costs.

Conclusion: Collective use of thyroid collars therefore does not seem to be a reasonable measure to optimize radiological protection during intraoral radiography.