Hi All, I would like to register a pair of nuclear medicine whole body bone scans of the same patient and make a subtraction image to evaluate for disease progression. To do this I must employ non-rigid registration techniques as patient posture is highly likely to be different between scans. I have managed this task fairly successfully using ImageJ in the past but would like to develop some code in IDL to integrate with Siemens e.Soft Workflow in the department. The only non-rigid registration procedure I have identified so far is Warp_TRI. This isn't ideal as it will require definition of many control points and will likely introduce error into the final registration. Is there any other appropriate IDL software out there for this purpose? Jamie