MTFTools for 2D & 3D MTF Measurement

Fork of MTF Tools used in calculating 3D MTF for Photon Counting CT. Implemented different segmentation for the spheres and rebinning functions.

MTFTools enables 2D / 3D line spread function (LSF), edge spread function (ESF), and modulation transfer function (MTF) calculation from a variety of test phantoms (wire, slit, edge/plane, wedge, circular rod, sphere) for X-ray, CT, and Cone-Beam CT systems.

This toolbox was developed at I-STAR Lab at Johns Hopkins University. Contact Pengwei Wu (pengwei.wu@jhu.edu) or Jeff Siewerdsen (jeff.siewerdsen@jhu.edu) with questions. This toolbox can also be downloaded from https://i-star.jhu.edu/downloads/.

This toolbox was first published in the following journal publication. Please kindly cite the following paper for using this toolbox: [1] P. Wu, J. M. Boone, A. M. Hernandez, M. Mahesh, and J. H. Siewerdsen, "Theory, method, and test tools for determination of 3D MTF characteristics in cone-beam CT," Medical Physics (2020).

Installation

Simply add src directory to MATLAB search path.

Usage

MTFTools is designed to be simple to use. Please checkout example scripts (examples folder) for MTF measurement using a variety of 2D or 3D test tools as listed below:

2D test tools

• Ex_2d_Edge.m: 2D edge test tool (2D ESF, MTF). See also Ex_2d_Edge_BinningMatch.
• Ex_2d_Slit: 2D slit or wire test tool (2D LSF, MTF).

3D test tools

• Ex_3d_Wire.m: 3D wire test tool (3D axial LSF, MTF). Checkout the pseudocode in our paper.
• Ex_3d_Sphere.m: 3D sphere test tool (3D ESF in any direction, MTF). See also Ex_3d_Sphere_DiffPhi (different \phi angle out of the axial plane), Ex_3d_Sphere_SliceAver (how sphere test tool reacts to slice averaging). Checkout the pseudocode in our paper.
• Ex_3d_Slit.m: 3D slit test tool (3D axial LSF, MTF).
• Ex_3d_Rod.m: 3D circular rod test tool (3D axial ESF, MTF).
• Ex_3d_AxialCircle.m: single axial slice from a circular test tool (3D axial ESF, MTF). See also Ex_3d_AxialCircle_DiffTheta (different \theta angle within the axial plane).
• Ex_3d_Plane.m: 3D plane test tool (3D ESF in any particular direction (perpendicular to the plane), MTF).
• Ex_3d_Wedge.m: 3D wedge test tool (3D ESF in any particular direction (perpendicular to the plane), MTF). Checkout the phantom design & pseudocode in our paper (for MTF that is 45 degree out of the axial plane).

Method Overview

One can find method overview as well as pseudocode for the wire, wedge, and sphere phantom in our paper (section 2.2.2 - 2.2.4).

Acknowledgement

Beta testers:

• Andrew Hernandez
• Xiaoxuan Zhang

External tools (modified to be used in this toolbox):

• Andrew Horchler (2021). circfit (https://github.com/horchler/circfit), GitHub. Retrieved February 27, 2021.
• Alan Jennings (2021). Sphere Fit (least squared) (https://www.mathworks.com/matlabcentral/fileexchange/34129-sphere-fit-least-squared), MATLAB Central File Exchange. Retrieved February 27, 2021.

Contributing

Contributions are always welcome. Please feel free to make a pull request.