Computing effective doses to pediatric patients undergoing body CT examinations

Area of Science:

• Medical Physics
• Radiological Dosimetry
• Pediatric Imaging

Background:

• Pediatric effective dose computation is crucial due to high CT radiation doses and increased CT utilization in children.
• Current methods for pediatric effective dose calculation are complex, necessitating simpler clinical approaches for radiologists and technologists.

Purpose of the Study:

• To determine pediatric effective doses for body CT scans.
• Utilize adult effective dose (E) per unit dose length product (DLP) coefficients.
• Incorporate energy imparted to children relative to adults.

Main Methods:

• Adult E/DLP coefficients were calculated using the ImPACT CT dosimetry spreadsheet at 120 kV.
• Monte Carlo modeling simulated energy imparted to water cylinders representing patients.
• Pediatric effective doses were derived using scaling factors for scan length, mAs, patient weight, and relative energy imparted (R(en)).

Main Results:

• Adult E/DLP values were approximately 16 microSv/mGy cm (males) and 19 microSv/mGy cm (females).
• Newborn R(en) values at 120 kV were 0.35 (chest) and 0.49 (abdomen).
• Pediatric chest CT doses were ~50% higher, and abdominal doses ~100% higher than adult doses at constant mAs.

Conclusions:

• Adult effective doses, derived from DLP data, can be effectively scaled.
• This scaling method provides corresponding pediatric effective doses for body CT examinations.
• The approach offers a simplified method for clinical use by radiologists and technologists.