Prog Med Phys.  2022 Dec;33(4):63-71. 10.14316/pmp.2022.33.4.63.

Effect of Bead Device Diameter on Z-Resolution Measurement in Tomosynthesis Images: A Simulation Study

• Fukui R
• Numata M
• Nishioka S
• Matsuura R
• Kida K
• Goto S

• KMID: 2537873
• DOI: http://doi.org/10.14316/pmp.2022.33.4.63

Abstract

Purpose
To clarify the relationship between the diameter of the simulated bead and the Z-resolution of the tomosynthesis image.
Methods
A simulated bead was placed on a 1,024×1,024×1,024-pixel base image. The diameters were set to 0.025, 0.05, 0.1, 0.2, 0.3, 0.7, 1.0, and 1.3 mm. A bead was placed at the center of the base image and projected at a simulated X-ray angle range of ±45° to obtain a projected image. A region of interest was placed at the center of the bead image and the slice sensitivity profile (SSP) was obtained by acquiring pixel values in the z-direction. The full width at half maximum of the SSP was defined as the Z-resolution and the frequency response was obtained by the 1-D Fourier transform of the SSP.
Results
Z-resolution increased with increasing bead diameter. However, there was no change in Z-resolution between 0.025 and 0.1 mm. The frequency response was similar to that of the Z-resolution, with a significant difference between 0.1 and 0.2 mm diameter.
Conclusions
Z-resolution is dependent on the diameter of the bead, which should be selected considering the pixel size of the tomosynthesis image.

Keyword

Tomosynthesis; Z-resolution; Frequency response; Bead method