Size-based optimization of pediatric CT protocols: balancing radiation dose and image quality

Area of Science:

• Radiology and Medical Imaging
• Pediatric Imaging
• Radiation Dose Optimization

Background:

• Pediatric chest CT protocols require optimization for radiation dose and image quality.
• Tube voltage selection is a key parameter influencing CT outcomes.
• Water Equivalent Diameter (WED) is a patient-specific metric relevant for dose estimation.

Purpose of the Study:

• To investigate a water equivalent diameter (WED)-based protocol for selecting tube voltage in pediatric chest CT.
• To optimize radiation dose and image quality by comparing 100 kV and 120 kV protocols.
• To determine optimal WED ranges for each tube voltage protocol.

Main Methods:

• Retrospective analysis of 100 pediatric patients undergoing chest CT.
• Division into 100 kV and 120 kV groups.
• Calculation of signal-to-noise ratio (SNR), central size-specific dose estimate (SSDEcenter), and WED.
• Normalization of dose and SNR by CTDIvol.
• Analysis of relationships between ratios and WED using fitting methods.

Main Results:

• SSDEcenter and SNR were significantly correlated with WED (R2 = 0.67 and R2 > 0.60, respectively).
• 100 kV protocol offered lower radiation dose for WED < 22 cm; 120 kV was better for WED > 22 cm.
• 100 kV yielded higher SNR for most organs when WED < 24 cm; 120 kV was superior above this threshold.
• The aorta consistently showed better SNR at 120 kV across all WEDs.

Conclusions:

• A WED-based protocol can guide tube voltage selection for pediatric chest CT.
• Recommend 100 kV for WED < 22 cm and 120 kV for WED > 22 cm for dose optimization.
• This approach aids in balancing radiation dose and image quality in pediatric patients.