[Rtk-users] Lateral blur in a FDK reconstructed volume

[Simon Rit]

Hi,
Yes, I think it's correct. To be sure you correctly understand it, you can
always do test cases with the source and detector positions, u v vectors in
the coordinate system of your object.
http://www.openrtk.org/Doxygen/classrtk_1_1ThreeDCircularProjectionGeometry.html#a0fb1475ed76a28cde24fac85eae18e1e
and then check the resulting angles and distances.
Simon

On Wed, May 11, 2022 at 2:15 PM Vincent Libertiaux <vl at xris.eu> wrote:

> On 10.05.22 22:54, Simon Rit wrote:
> > Hi Vincent,
> > RTK can parametrize any orientation of the detector with the three
> > angles GantryAngle, InPlaneAngle, OutOfPlaneAngle. 0.025° seems very
> > small indeed! I don't know how much you know about software B but the
> > easiest would be to have either the projection matrix or the source
> > position, detector position, u axis and v axis in patient/object
> > coordinates to derive the RTK parameters.
> > Good luck with this!
> > Simon
>
> Hi Simon !
>
> Unfortunately, I don't have access to B projection matrices.
>
> As for the detector orientation in RTK, I have made this picture to make
> sure I understand properly how to use the gantry angle to achieve my
> desired geometry:
>
> https://ibb.co/J3H8z9M
>
> The cyan detector is the default configuration with a 0° gantry angle.
> The blue detector is at a gantry angle of alpha (largely exaggerated for
> the sake of clarity).  So in order to simulate an out-of-plane rotation
> of the detector around its vertical axis, I should translate this blue
> detector so that its center matches the coordinates of the cyan one, and
> translate the source accordingly (along the black vectors on the
> picture) ?  I assume that proj_iso_x/y and source_x/y are expressed in
> the gantry system of coordinates (local) ?
>
>
> Thank you again for your feedback,
>
> kindest regards,
>
> V.
>
>
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