Differences in effective dose estimation from dose–area product and entrance surface dose measurements in intravenous urography

Introduction: Given the high radiation tissue sensitivity of pediatric patients, it is necessary to monitor their received dose to optimize radiation protection. The first aim of this study was to evaluate the entrance surface dose (ESD) in pediatric patients undergoing a chest X-ray at the main hospital of Dezful, Iran. The second aim was to compare our results with the established dose reference levels (DRLs). Materials and Methods: The studied population included 204 pediatric patients less than 15 years who were referred to as chest X-ray. A calibrated dose area product meter (DAP-meter) with permanent installation on the X-ray unit was used to radiation dose measurements. For each patient, the demographic data, exposure parameters and the dose read by DAP-meter were recorded and ESD was calculated using a standard mathematical formula. Results: The average value of ESD was 119 μGy in patients less than 15 years. This value was 51.3, 122.3, 131.5 and 171.2 μGy for the age groups for less than 1 year, 1 to 5 years, 5 to 10 years and 10 to 15 years, respectively. A statistically significant difference was seen between ESD values in different age groups (P<0.001), whereas no statistical difference was seen between ESD values in girls and boys (P =0.993). Conclusion: Pediatric patients in hospital investigated (except age group less than 1 year) are subjected to unnecessary radiation exposure, especially due to the use of non-optimize X-ray protocols.

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Estimation of the radiation dose for dental spectral cone-beam CT

Dentomaxillofacial Radiology ◽

10.1259/dmfr.20200372 ◽

2020 ◽

pp. 20200372

Author(s):

Kaan Orhan ◽

Ruben Pauwels ◽

Yi Chen ◽

Dandan Song ◽

Reinhilde Jacobs

Keyword(s):

Radiation Dose ◽

Effective Dose ◽

Cone Beam Ct ◽

Cone Beam ◽

Dose Area Product ◽

Ion Chamber ◽

Effective Doses ◽

Artefact Reduction ◽

Area Product ◽

Dose Measurements

Objectives: The purpose of this study was to estimate the radiation dose for a dental spectral cone-beam CT (SCBCT) unit at different scanning parameters. Methods: Radiation dose measurements were performed for a commercially available dental SCBCT. Scans were obtained at different exposure times and fields of view (FOV), both for non-spectral (25 × 18 cm, 14 × 18 cm, 14 × 12 cm, 9 × 9 cm, 6 × 6 cm) and spectral modes (14 × 18 cm, 14 × 12 cm, 9 × 9 cm, 6 × 6 cm) with the tube voltage alternating between 80 and 110 kV for spectral mode, and fixed at 110 kV for non-spectral mode. An ion chamber was used for air kerma and dose area product (DAP) measurements. The effective dose was estimated based on the mAs using previously published logarithmic curves for CBCT units with a similar X-ray spectrum. Results: The adult effective dose, in non-spectral mode, was 44-269µSv for small FOVs, 131-336µSv for the medium FOV, and 163-476µSv for the large FOV. In spectral mode, the estimated adult effective doses were 96-206µSv for small, 299µSv for medium and 372µSv for large FOV protocols. Pediatric effective doses were estimated to be 75% higher than corresponding adult doses. Conclusion: SCBCT showed comparable doses with other CBCT devices, but DAP values were generally above currently published DRLs. Spectral imaging might allow for artefact reduction at comparable dose levels, which should be assessed in further image quality studies at both a technical and diagnostic level.

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