Tohoru Takeda

Development of high-resolution x-ray CT system using parallel beam geometry

For fine three-dimensional observations of large biomedical and organic material samples, we developed a high-resolution X-ray CT system. The system consists of a sample positioner, a 5-μm scintillator, microscopy lenses, and a water-cooled sCMOS detector. Parallel beam geometry was adopted to attain a field of view of a few mm square. A fine three-dimensional image of birch branch was obtained using a 9-keV X-ray at BL16XU of SPring-8 in Japan. The spatial resolution estimated from the line profile of a sectional image was about 3 μm.

Cardiac Wall Motion Obtained By Digital Subtraction Angiography (Dsa) Without Contrast Material

Without contrast material, the cardiac wall motion can be clearly described by using subtraction method. The subtracted x-ray images from an end diastolic phase image gives sufficient information to evaluate cardiac motion quantitatively. Clinical validity is discussed on the actual data and several observations to distinguish abnormality of cardiac motion are obtained. In normal cases, the contraction of the cardiac wall is approximately symmetrical to long axis. The degree of contraction in the apex was significantly less than that in anterior wall, and that in inferior wall was slightly greater than that in anterior wall. The profile analysis showed that greater contraction was occurred in the inferior wall, and probably, the reason may be the upper forward shift of center of gravity. The localized abnormality of the contraction were found in the area of previous myocardial infarction as dyskinesis, akinesis, and hypokinesis. The phase images of regional wall motion showed that synchronous contraction occurred in the normal cases, whereas asynchronous contraction occurred in the ischemic cases. The amplitude image of that showed the degree of contraction clearly.