Doses under automatic exposure control (AEC) for direct digital radiographic (DDR) X-ray systems

Area of Science:

• Medical Physics
• Radiological Imaging Technology

Background:

• Current X-ray system guidelines use 'Baseline ± X %' tolerances for automatic exposure control (AEC) device performance.
• This tolerance is not applicable during commissioning when a baseline has not yet been established.

Purpose of the Study:

• To establish mean radiation doses for direct digital radiography (DDR) X-ray systems operating in AEC mode.
• To provide reference values for performance comparisons during commissioning and quality assurance.

Main Methods:

• Dose measurements were conducted on 29 DDR detectors from three manufacturers under AEC operation.
• Two distinct testing protocols were employed: water-equivalent phantoms and an aluminum block at the tube head.
• Patient exit doses were measured with and without an antiscatter grid.

Main Results:

• Using an aluminum block, average patient exit doses were 4.6 μGy (grid) and 4.0 μGy (no grid).
• With water phantoms, average doses were 17.1 μGy (grid) and 5.4 μGy (no grid).
• The testing configuration significantly influenced the measured radiation dose.

Conclusions:

• The study highlights the variability in measured doses based on the testing methodology.
• Established mean doses offer a practical reference for DDR system performance evaluation in AEC mode.
• Standardized testing protocols are essential for reliable AEC performance assessment.