Extended detail contrasts for TO.10 use on flat panel detector fluoroscopy systems

Area of Science:

• Medical Physics
• Radiological Imaging
• Image Quality Assessment

Background:

• The Leeds Test Object Ten (TO.10) is standard for subjective Threshold Contrast Detail Detectability (TCDD) in fluoroscopy.
• Current TO.10 contrast calibration is limited to specific voltage and filtration settings, which are often not met by modern fluoroscopic systems.
• Independent control of voltage and filtration in flat panel systems complicates standard TO.10 testing.

Purpose of the Study:

• To expand the range of TO.10 contrasts for routine fluoroscopy testing.
• To provide methods for calculating TO.10 contrasts at commonly encountered voltage and copper filtration settings.
• To enhance the accuracy and reproducibility of image quality assessments in fluoroscopy.

Main Methods:

• Developed a 3D interpolation/extrapolation model in MATLAB® to generalize contrast calculations.
• Utilized a multivariate log-polynomial function for estimating contrasts.
• Both methods use existing calibrated contrasts to predict values at non-standard conditions.

Main Results:

• Results presented as Threshold Detection Index ([Formula: see text]) curves, fitted using a second-order polynomial.
• The methods demonstrated higher accuracy for unprescribed conditions.
• Results showed reproducibility with consistent input air kerma rate (IAKR) from automatic dose rate controls (ADRC).

Conclusions:

• Calculations of TO.10 contrasts at non-standard conditions improve absolute image quality estimation in fluoroscopy.
• Extended TO.10 detail contrasts enhance TCDD testing for fluoroscopy units.
• The methods facilitate absolute assessments and inter-system comparisons of fluoroscopic image quality for clinical physicists.