Estimating the effective dose to children undergoing heart investigations--a phantom study

Area of Science:

• Medical Physics
• Radiological Sciences
• Pediatric Imaging

Background:

• Accurate estimation of effective dose from dose-area product (DAP) is crucial for radiation protection in pediatric radiology.
• Congenital heart disease examinations involve complex imaging protocols requiring specific conversion factors (F).

Purpose of the Study:

• To assess the conversion factor (F) for deriving effective dose from DAP measurements in pediatric patients undergoing radiological examinations for congenital heart diseases.
• To establish reliable F values for different child sizes and X-ray beam projections.

Main Methods:

• Utilized anthropomorphic phantoms (1-year-old and 5-year-old) irradiated under simulated heart examination conditions.
• Measured organ doses with thermoluminescent dosimeters to calculate effective dose (mSv) per International Commission on Radiological Protection (ICRP) guidelines.
• Simultaneously measured dose-area product (DAP) values (Gy cm²).
• Calculated the conversion factor (F) as the ratio of effective dose to DAP.

Main Results:

• The conversion factor (F) showed a strong correlation with phantom size and a lesser correlation with irradiation projection.
• Significant deviations in F were observed at major beam angulations and lateral projections compared to frontal views.
• Recommended F values for PA and lateral views were provided for children weighing 7-11 kg (1.8 and 1.4, respectively) and 15-26 kg (0.9 and 0.7, respectively).

Conclusions:

• Effective dose in pediatric heart investigations can be reliably estimated from DAP values using size and projection-specific conversion factors.
• The study provides practical F values to enhance radiation dose assessment accuracy in pediatric cardiac imaging.
• Implementation of these factors can aid in optimizing radiation protection strategies for children undergoing these examinations.