Filtered backprojection with 2 detectors

Hey everyone !

Aim : Detect filtered backprojection artefact on early scintigraphy and correct them.

Summary :
I created a 4D phantom. It’s simulate the projection of an early scintigraphy. The interesting point, it’s that the bladder evolve in time and i think, it s responsible of the artefact.
I want to simulate the FBP of my 4D projections, so i can reconstruct the tomoscintigraphy and detect the artefact.
In the hospital we use a gamma camera with 2 detectors. The position of the detectors from each others can be in H (180° from each others) or in L (90° from each others).

Problem :
I have two detectors, how can I add the information about the 2 detectors FBP so I can reconstruct the tomoscintigraphy.
I don’t think that an algebric sum of the two FBP is the answer.

Solution that i tried :
I used the Xlib plugins (filtered bacckprojection) in Fiji.
It asks for two main arguments :

1. Angle for reconstruction.
2. Projection ID’s used for the reconstruction.

So I wanted to simulate the FBP of 2 detectors in L (90° from each others).
The first detectors (D1) : goes from 0° to 179 (matlab notation)
The second detectors (D2) : goes from 90° to 269° (matlab notation)

(The projections of 0° is acquired simultaneously with 90° projections, 1° with 91°, etc. ==> sinogram with dimensions (182, 270))

I gave those arguments to the plugins :

1. Angle for reconstruction : 0° to 269° incremented every 1°
2. Projectons ID’s used for the reconstruction : 0°,90°,1°,91°,…,179°,269°

Questions :
Any tips two combine the information of the 2 detectors for the reconstruction ?
Did i use correctly Xlib plugins ?

Thank’s for your answers.