A non-linear programming method for optimizing parallel-hole collimator design Simmons, G. H. ; Christenson, J. M. ; Kereiakes, J. G. ; Bahr, G. K. Abstract Publication: Physics in Medicine and Biology Pub Date: September 1975 DOI: 10.1088/0031-9155/20/5/007 Bibcode: 1975PMB....20..771S