xample main-files as a basis and construct the class object by using the </span><span style=' font-family: monospace;'>options</span><span> struct: </span><span style=' font-family: monospace;'>A = forwardBackwardProjectCT(options)</span><span>. 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 </span><span style=' font-family: monos