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

[Vincent Libertiaux]

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.