Effect of the geometry of the intraoral position-indicating device on effective dose.

ABSTRACT

OBJECTIVE: The objective of this study was to calculate and compare the effective dose and to estimate risk from the use of intraoral position-indicating devices of differing geometries. STUDY DESIGN: Thermoluminescent dosimeters were placed at selected sites in the upper portion of a tissue-equivalent human phantom to record the equivalent dose to weighted tissues and organs. The phantom was exposed to simulated complete mouth surveys with either a long (29.8 cm) or short (19.6 cm) round open-end position-indicating device, a long (35.3 cm) or short (23.3 cm) rectangular open-end position-indicating device, or a pointed (29.6 cm) closed-end position-indicating device. RESULTS: The effective dose was calculated as the sum of the equivalent doses to each organ or tissue multiplied by that organ or tissue's weighting factor. The salivary glands were included as part of the remainder. The effective dose ranged from 362 micro Sv for the pointed position-indicating device, to 63 micro Sv for both the long and the short rectangular position-indicating devices. CONCLUSIONS: These effective doses were calculated to represent a probability for stochastic effects that range in magnitude from 26 x 10(-6) to 4.6 x 10(-6).