Effects of Tube Voltage on Phase-Contrast Imaging for Different Microfocus X-Ray Tubes

Jianbao Gui, Zhanli Hu, Peter Z. Wu, Hairong Zheng

Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.

DOI: 10.4236/eng.2013.510B121                

Abstract

In the past decade, phase-contrast imaging (PCI) has become a hot research with an increased improvement of the image contrast with respect to conventional absorption radiography. In this paper, effects of tube voltage (kVp) on propagation-based phase-contrast imaging have been investigated with two types of microfocus x-ray tubes, a conventional sealed x-ray tube with the focal spot size of 13 - 20 μm and an open x-ray tube with minimum focal spot size less than 2 μm. A cooled x-ray CCD detector with the pixel size of 24 μm was used to acquire digital images. Two thin plastic sheets with different thickness were used as radiography phantoms. Two different phenomena were observed for the two x-ray tubes. For the open tube, phase-contrast effect has a slight drop with the increasing of tube voltage, however, it is opposite for the sealed tube. A further investigation indicates that the variation of focal spot size causes the abnormal result for the sealed tube. It also shows that phase-contrast effect is more sensitive to focal spot size than tube voltage.

Keywords

Phase-Contrast Imaging; Edge Enhancement; X-Ray; Tube Voltage

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	X. Z. Wu and H. Liu, “Clinical Implementation of X-Ray Phase-Contrast Imaging: Theoretical Foundations and Design Considerations,” Medical Physics, Vol. 30, No. 8, 2003, pp. 2169-2179. http://dx.doi.org/10.1118/1.1593836
[2]	A. Pogany, D. Gao and S. W. Wilkins, “Contrast and Resolution in Imaging with a Microfocus X-Ray Source,” Review of Scientific Instruments, Vol. 68, No. 7, 19997, pp. 2774-2782. http://dx.doi.org/10.1063/1.1148194
[3]	X. Z. Wu and H. Liu, “Phase-Space Formulation for Phase- Contrast X-Ray Imaging,” Applied Optics, Vol. 44, No. 28, 2005, pp. 5847-5854. http://dx.doi.org/10.1364/AO.44.005847
[4]	F. D. Edwin and R. P. Ronald, “Quantification of the Effect of kVp on Edge-Enhancement Index in Phase-Contrast Radiography,” Medical Physics, Vol. 29, No. 6, 2002, pp. 999-1002. http://dx.doi.org/10.1118/1.1477416
[5]	F. D. Edwin, et al., “Characterization of the Phase-Contrast Radiography Edge-Enhancement Effect in a Cabinet X-Ray System,” Physics in Medicine and Biology, Vol. 51, No. 1, 2006, p. 21. http://dx.doi.org/10.1088/0031-9155/51/1/002
[6]	F. D. Edwin, R. P. Ronald and R. P. David, “Quantification of the Effect of System and Object Parameters on Edge Enhancement in Phase-Contrast Radiography,” Medical Physics, Vol. 30, No. 11, 2003, pp. 2888-2896. http://dx.doi.org/10.1118/1.1617430