Hello all, I've been trying to create the background source with the NEMA phantom for a long time and finally accomplished it with the use of "confine" and "forbid" commands. I confirmed the source distribution each time by using /gate/source/FictiveSource/visualize command and I could get the image as attached(the alignment of the cold sources are a bit modified from the original NEMA phantom), which has a uniform distribution with complex shape. But, even it doesn't give me any error upon the visualization process, when I start the simulation, it always gives me an error as, ************************************* LoopCount = 100000 Either the source distribution >> confinement or any confining volume may not overlap with the source distribution or any confining volumes may not exist If you have set confine then this will be ignored for this event. ************************************* *** Break *** segmentation violation I checked my code but I don't understand what the "distribution >> confinement" means... My macros are very messy but if you are interested in this problem, please take a look at them. It should work when you start "test.mac" If you have any question or suggestion, I'll gratefully wait for it. Thank you. Taku -- Hokkaido University, Graduate school of medicine, medical physics and engineering D1 Taku Yamanaka <a href="mailto:takuyama@med.hokudai.ac.jp" target="_blank">takuyama@med.hokudai.ac.jp</a> --