Effective dose and image quality for different patient sizes during AP upper abdominal radiography: A phantom study

Area of Science:

• Radiological physics
• Medical imaging
• Radiography

Background:

• Medical imaging of obese patients presents challenges in protocol selection and adhering to the ALARA principle.
• Optimizing image quality (IQ) and effective dose (ED) is crucial for patient safety and diagnostic accuracy.

Purpose of the Study:

• To assess the impact of increasing body part thickness on IQ and ED in upper abdominal radiography.
• To determine optimal exposure settings for larger patients undergoing abdominal X-rays.

Main Methods:

• Simulated varying abdominal sizes using an anthropomorphic phantom with added fat layers (6-16 cm).
• Utilized diverse tube potentials (70-110 kVp), automatic exposure control (AEC), and a 120 cm source-to-image distance.
• Assessed IQ via visual grading analysis and calculated ED using Monte Carlo simulations (PCXMC 2.0).

Main Results:

• Image quality significantly decreased (p=0.006) with increasing phantom thickness across all tube potentials.
• Highest IQ scores were achieved at lower tube potentials (70/75 kVp), while higher potentials reduced IQ.
• Effective dose significantly increased (p<0.001) with greater phantom thicknesses.

Conclusions:

• Higher effective doses were observed with lower tube potentials.
• Employing AEC with high tube potentials (105/110 kVp) significantly reduces effective dose with acceptable IQ for thicker abdomens.
• Higher tube potentials are recommended for patients with thicker abdomens to decrease effective dose.