It depends. What exactly is "dicom image"? Maybe it is teh name of a file, which is stored on a slow network drive. Then store it on a local disk or install a faster network connection. Maybe the file is stored locally already on a very busy disk. Then reduce the load of this disk caused by otehr applications. Maybe the disk is slow due to damaged sectors? Maybe your file is huge an the speed is limited by the memory or the CPU. Then install more RAM (or quit other applications) or buy a faster CPU. Does your regionprops3 (I assume not "...pros", by the way) access the graphics card at all?
Possibly the job is simply hard and there is no magic swicth to increase the speed beside running it on a faster machine or with different inputs. If you post more details, this question could be answered more precisely. Perhaps 'All' is more than you actually need?
