Estimation of dose-area product-to-effective dose conversion factors for neonatal radiography using PCXMC

Area of Science:

• Medical Physics
• Radiological Sciences
• Pediatric Imaging

Background:

• Accurate estimation of effective dose (E) in neonatal radiography is crucial for radiation protection.
• Existing dose conversion factors may not be optimized for the unique anthropometry of neonates.
• Monte Carlo simulations are a standard for detailed radiation dose assessment.

Purpose of the Study:

• To compute dose-area product (DAP) to effective dose (E) conversion factors specifically for neonatal radiography.
• To validate these conversion factors against detailed Monte Carlo simulations.
• To assess the impact of beam quality and patient size on dose conversion.

Main Methods:

• Utilized the PCXMC Monte Carlo software with seven neonatal patient models (0.5-6.0 kg).
• Calculated conversion factors for a range of tube potentials (50-80 kVp) and beam filtrations (3.0 mm Al, 3.0 mm Al + 0.1 mm Cu).
• Compared calculated effective dose values using conversion factors with customized PCXMC simulations for 133 neonatal radiographs.

Main Results:

• DAP-to-effective dose conversion factors were determined for chest, abdomen, and chest-abdomen neonatal radiographs.
• For a 3.0-kg neonate at 60 kVp/3.0 mm Al, factors were 2.58, 1.90, and 1.91 μSv/(mGy cm²) for chest, chest-abdomen, and abdomen, respectively.
• The average dose difference between conversion factors and customized simulations was 16%, with under-collimation being a key factor in disagreement.

Conclusions:

• The computed conversion factors provide a reliable method for estimating effective dose from DAP measurements in neonatal radiography.
• The accuracy of dose estimation is influenced by factors such as beam filtration, tube potential, and collimation accuracy.
• These findings support improved radiation protection strategies in pediatric diagnostic imaging.