A new method to measure directional modulation transfer function using sphere phantoms in a cone beam computed...

Area of Science:

• Medical Imaging
• Radiology
• Image Reconstruction

Background:

• Cone beam computed tomography (CBCT) systems require accurate assessment of image quality.
• Directional modulation transfer function (MTF) is a critical metric for evaluating imaging performance, but its measurement in 3D is challenging.

Purpose of the Study:

• To develop and validate a novel method for measuring directional modulation transfer function (MTF) in CBCT systems.
• To assess the spatial variation of 3D MTFs using sphere phantoms.

Main Methods:

• A modified Richardson-Lucy (RL) deconvolution method was employed to estimate directional plane spread functions (PlSFs) from reconstructed sphere phantoms.
• Directional MTFs were derived from the Fourier transform of the estimated directional PlSFs.
• The FDK reconstruction algorithm was modeled in local regions for spatially varying MTF analysis.

Main Results:

• The proposed method successfully estimated directional MTFs using sphere phantoms in CBCT.
• Measured directional MTFs showed excellent agreement with simulated ideal MTFs across simulation and experimental data.
• Quantitative evaluation using full-width at half-maximum (FWHM) and full-width at tenth-maximum (FWTM) confirmed the accuracy of the method.

Conclusions:

• The developed method provides an effective approach for measuring directional MTFs in CBCT systems.
• This technique enables accurate characterization of spatially varying 3D image quality.
• The findings demonstrate the potential for improving CBCT imaging performance assessment.