Patient-size-dependent radiation dose optimisation technique for abdominal CT examinations

Area of Science:

• Medical Physics
• Radiological Imaging
• Radiation Protection

Background:

• Computed tomography (CT) scans involve relatively high patient radiation doses, necessitating a balance between dose and image quality.
• Optimizing CT scanning parameters is crucial for patient safety and effective risk-benefit analysis.

Purpose of the Study:

• To develop and evaluate a patient-dependent CT scanning parameter optimization technique for abdominal examinations.
• To minimize radiation dose to patients while maintaining diagnostic image quality by utilizing patient diameter.

Main Methods:

• Cylindrical phantoms (16-40 cm diameter) were used to simulate patients of varying sizes.
• CT scanning parameters were systematically varied, and relationships between image quality, dose, and patient size were established.
• Image noise was quantified using region of interest software, and CT dose index in air was measured and corrected for phantom attenuation.

Main Results:

• Exposure settings (milliampere seconds) were reduced by up to 82% for smaller phantoms compared to standard settings.
• Detector signal reduction reached up to 93% for smaller phantoms, indicating lower energy deposition.
• Object-specific scanning parameters reduced incident radiation by up to 86% for smaller objects while maintaining image quality.

Conclusions:

• Patient-specific optimization of CT scanning parameters, based on transverse diameter, can substantially reduce radiation dose.
• This approach offers significant dose savings for pediatric and small-statured adult patients undergoing abdominal CT.
• Implementing patient-dependent optimization is key to improving radiation safety in diagnostic imaging.