Performing MLEM with Response Matrix for 4pi Imager and 1x3 Vector Input

[a.glick]

TL;DR

I am studying 4pi kinematic imaging with a neutron scatter camera and want to perform MLEM given det1, det2, and theta values for my cones.

I have a response matrix for my 4pi imager to perform MLEM that has dimensions:

(16 x 16 x 18) x (72 x 36) which is Observation Bins x Source Bins.

I'm told that I can use MLEM to create an image by feeding in a 1x3 vector of

det1, det2, theta

into the MLEM algorithm. Where det1, det2 are the 2 detectors a particle interacts with in the kinematic imaging and theta is the opening angle of a cone of probability for the particle's incident direction. However every paper I've read says I need a vectorized image (or simple backprojection) that has a 1 x (72 x 36) dimensional form. How can I do the MLEM iteration in my case?

 

[Mark44]

You'll have a much better chance of getting answers to your questions if you provide more information.

• What is MLEM? We shouldn't need to do a search to find what this algorithm is. A link to a description of this algorithm would be helpful.
• What is 4pi kinematic imaging?