Dental radiography technique and equipment: How they influence the radiation dose received at the level of the thyroid gland

Abstract 

Purpose

The aim of this study was to investigate the influence that collimator and technique choice had on the radiation dose detected at the thyroid gland position, during intra-oral examinations of the upper and lower teeth. Radiation dose reduction from a different perspective, other than the application of lead–rubber shielding, was addressed.

Methods

A study was performed at a regional dental school with the use of a phantom head/neck and a radiation dosemeter, to measure the radiation dose detected at the thyroid gland position. The radiation dose was assessed for two intra-oral techniques (paralleling and bisecting angle), and two collimators (rectangular and circular). The radiation dose was also assessed with and without the application of a thyroid shield. Standard descriptive statistics, followed by inferential statistics were applied to the data.

Results

There was a significant reduction in the radiation dose detected at the thyroid gland position, when employing the paralleling technique (66.7%) and rectangular collimator (45.5%). Other factors, for example the tooth/teeth under examination, were also found to influence the radiation dose detected.

Conclusion

Radiation dose reductions using the paralleling technique and rectangular collimator were outlined. The use of this low dose combination within dental practices remains limited, therefore, continued awareness and acceptance of radiation hazards need to be addressed.

Keywords: Oral radiology, Radiation dose reduction