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The effect of focal spot size on the spatial resolution of variable resolution X-ray CT scanner
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H. Arabi   , A.R. Kamali Asl , S.M. Aghamiri |
| , A_R_Kamali@yahoo.com |
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Abstract: (15099 Views) |
| Background: A variable resolution X-ray (VRX) CT
scanner provides a great increase in the spatial
resolution. In VRX CT scanners, the spatial resolution
of the system and its field of view (FOV) can be
changed according to the object size. One of the main
factors that limit the spatial resolution of VRX CT
scanner is the effect of the X-ray focal spot. Materials
and Methods: A theoretical study of the effect of X-ray
focal spot on the spatial resolution of VRX CT is
presented in this paper. In this study, we used the
parameters of an actual VRX CT scanner. By using the
relevant equations, the effects of foal spot sizes of
0.6 and 0.1 mm were calculated on spatial resolution
of the system at various opening half angles. Results:
Focal spot size of 0.6 mm had no significant effect on
spatial resolution of the system for opening half
angles of above 14°. Even focal spot sizes of larger
than 0.6 mm could not affect the spatial resolution of
the system. For opening half angles of below 14°,
foal spot size of 0.6 mm limited the spatial resolution
of the system to 5.7 cycle/mm and caused great
spatial resolution non-uniformity along the detector
length. Conclusion: By focal spot size of 0.1 mm,
the spatial resolution varied as a function of the
opening half angle and increased to more than 30
cycle/mm. Additionally, focal spot size of 0.1 mm
minimized the spatial resolution non-uniformity along
the detector length. Iran. J. Radiat. Res., 2010 8 (1):
37-43 |
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| Keywords: Variable resolution X-ray (VRX) CT scanner, focal spot size, spatial resolution. |
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Full-Text [PDF 331 kb]
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Type of Study: Original Research |
Subject:
Medical Physics
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