Eatimation of effective doses from a dental cone beam computed tomographic scanner

Abstract

Objective To calculate effective dose based on the dose-area Product (DAP) measured in dental cone beam computed tomograhic (CBCT) scanning and using a conversion coefficient. Methods The method of the DAP was used to calculate the effective dose from KODAK 9500 dental CBCT scanner with fields of view (FOV) of 16 cm×15 cm and 12 cm×8 cm. The DAP-values (mGy·cm2) were measured using a transmission ionization chamber connected to an electrometer (Doseguard 100, RTI Electronics AB, Sweden) and the chamber was placed directly on the exit of the X-ray tube. All measurements were repeated three times and averaged on each FOV data. The conversion coefficient of 0.080 μSv/mGy·cm2 was used to estimate the effective dose on the basis of DAP values, which was quoted from a literature. Results DAP values were found between the two FAOs to vary from 512 to 1 083 mGy·cm2, and the effective doses calculated with 0.080 μSv/mGy·cm2 were 41 to 87 μSv. The effective doses given in this paper was lower than those reported in other literatures. Conclusions DAP measurement was found to be well defined and easy-to-use method of determining effective dose for some CBCT Units. However, determination of specific conversion coefficient in the CBCT must be further developed. Key words: Cone beam computed tomography(CBCT); Dose-area product(DAP); Effective dose; Conversion coefficient