Tierärztliche Hochschule Hannover Entwicklung von Methoden zur ...

SUMMARY
contrast increased to the cortical and decreased to hydroxylapatite or bone meal using the
µCT 80.
A density calibration by means of using bone meal filled or paraffin wax filled bores in
LAE442-pins, turned out to be feasible with the XtremeCT. A highly linear correlation
between decreasing implant density and corresponding CT-numbers for both bone meal filled
(R 2 = 0,995) or paraffin wax filled (R 2 = 0,997) pins was found.
Mainly because of the low contrast resolution, the XtremeCT proved to be suitable for small
animal imaging to only a limited extent.
The XtremeCT’s large FOV, measuring 126 mm is advantageous since it allows scanning
with a high spatial resolution (41 µm) of large laboratory animals like e.g. rabbits. The
unchangeable tube voltage (60 kV) turned out to be disadvantageous. This way, the mean
photon energy, and therefore the contrast-to-noise-ratio, could not be altered. Hence, the
XtremeCT can’t optimally display low contrast objects. For this reason the XtremeCT turned
out to be not suitable for imaging of degradable magnesium implants when low contrast
structures around or within the implant are to be analysed.
A variable tube voltage would be recommendable for the XtremeCT in the future and would
improve the suitability for small animal imaging considerably. A choice of different convolution
kernels, adapted to varying anatomical structures, would be desirable as well.
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