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<div>Hello Simon,</div>
<div>I try to handle a planar tomosynthesis where the flat panel detectors are arranged in a 3x3 matrix. For each view,</div>
<div>the object and the detector are aligned, so that the "line" from xray source through the object center and through the middle</div>
<div>of the detector. As you told me, I do not change the size of the object. The problem is, that the object in the orhogonal view (center)</div>
<div>covers the whole detector. For any other view some parts of the object are outside of the cone beam and so are not part of the</div>
<div>projection image (see attached pdf). The detector's size is fixed and the object's size as well.</div>
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<div>Best regards,</div>
<div>Robert</div>
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<div style="margin:0 0 10px 0;"><b>Gesendet:</b> Dienstag, 03. März 2015 um 16:37 Uhr<br/>
<b>Von:</b> "Simon Rit" <simon.rit@creatis.insa-lyon.fr><br/>
<b>An:</b> "Robert Calließ" <Robert.Calliess@gmx.de><br/>
<b>Cc:</b> "rtk-users@openrtk.org" <rtk-users@openrtk.org><br/>
<b>Betreff:</b> Re: [Rtk-users] sart for planar tomosynthesis</div>
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<div>Hi Robert,</div>
I'm not sure I understand what your tomosynthesis does. But what I would do is fix all geometric parameters to constant values, including the angles (gantry, inplane, outofplane), except SourceOffsetX, SourceOffsetY, ProjectionOffsetsX, ProjectionOffsetsY. In any case, I would not modify the object size and positions, this is a given in practice. If you want to cover your object, just use a larger detector.</div>
Good luck,</div>
Simon</div>
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<div class="gmail_quote">On Tue, Mar 3, 2015 at 3:56 PM, "Robert Calließ" <span><<a href="Robert.Calliess@gmx.de" target="_parent">Robert.Calliess@gmx.de</a>></span> wrote:
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<div>Hello,</div>
<div>I know that RTK's primary use is the field of a circular trajectory. But if one would</div>
<div>use the the RTK for tomosynthesis the first choice's algorithm would be the</div>
<div>S-ART.</div>
<div> </div>
<div>Following situation. The Focus is fixed. The object only moves in the xy plane and also the</div>
<div>detectors, for instance flat panel detectors. So that a virtually line would always goes from</div>
<div>the focus through the object center and ends in the detector's center.</div>
<div>I wonder how to handle the different geometry settings for this kind of reconstruction.</div>
<div>What I mean is, that with a circular trajector the parameters FOD, FDD and ODD always</div>
<div>remain the same because we are rotationg around an axis. But for the case of planar</div>
<div>tomosynthesis the FOD, FDD will be different from the orthogonal view.</div>
<div>Usually we calculate the physical size of the object based on the FOD and FDD to get sure</div>
<div>that the object fits within the cone.</div>
<div>But now for the case of a planar tomosynthesis do one need to recalculate the object size</div>
<div>so that the object fits into the current cone beam or do one work with the object size calculated</div>
<div>for the center view (orthogonal view, where the original FOD, FDD are given) ?</div>
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<div>I think if I would resize the object for every viewing position this would change a lot for the</div>
<div>reconstruction result as I also change the "ray paths".</div>
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<div>Does anyone has experiences with this kind of reconstruction ?</div>
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<div>best regards,</div>
<div>Robert C.</div>
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