Design and Validation of Synchronous QCT Calibration Phantom: Practical Methodology

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Radiology

Background:

• Quantitative computed tomography (QCT) offers advanced bone assessment beyond dual x-ray absorptiometry.
• Whole-body spiral CT scanners provide rapid scanning for QCT, unlike slower peripheral scanners.
• Accurate calibration is crucial for reliable QCT bone densitometry.

Purpose of the Study:

• To design and evaluate a novel, homemade calibration phantom for QCT.
• To assess the accuracy and precision of this phantom using a whole-body spiral CT scanner.
• To provide practical guidance for QCT bone mineral density quantification.

Main Methods:

• A QCT calibration phantom was designed using ABAQUS software.
• The phantom utilized potassium phosphate (K2HPO4) solutions of varying concentrations (0-1200 mg/cc) as reference standards.
• Whole-body spiral CT scans were performed for phantom evaluation.

Main Results:

• The homemade phantom demonstrated high accuracy and precision, with errors generally below 5.1%.
• A strong linear correlation (R² = 0.99) was observed between CT numbers and K2HPO4 concentrations.
• The phantom proved effective for performance assessment of the QCT method.

Conclusions:

• The developed homemade QCT calibration phantom is accurate and precise for bone mineral density quantification.
• This phantom can enhance QCT bone densitometry, especially when using widely available whole-body spiral CT scanners.
• The study offers practical directions for implementing this phantom in clinical QCT assessments.