ass object. The recommended 
% method is to use one of the example main-files as a basis and construct the 
% class object by using the |options| struct: |A = forwardBackwardProjectCT(options)|. 
% Both the improved Siddon and volume-based ray tracers are available  with this 
% method as well as automatic PSF if selected. With this method, it is also possible 
% to easily affect the initial position of the source by using the |options.offangle| 
% value.
% 
% Alternatively, it is possible to construct the 