How do I use particle sources in DICOM instances

Hi Geant4ers:
Recently I have been testing my radioactive seed using DICOM examples, and I have used parallel geometry to implant this radioactive seed into the model constructed by DICOM. Now I’m going to use GPS to confine particles to the radioactive seed that I’ve created. In my past experience I’ll use: / GPS /pos/confine .
Unfortunately, my idea didn’t work out.

G4WT2 > Raw position -1.21677,-2.83726,-0.809618
G4WT2 > Rotated position (-1.21677,-2.83726,-0.809618)
G4WT2 > Rotated and translated position (-1.21677,-2.83726,-0.809618)
G4WT2 > Reference vectors for cosine-law (0.919051,-0.394138,0) (0.099983,0.23314,-0.967289) (-0.381246,-0.888989,-0.253675)

The process stays in a thread until the program is killed.
So I would like to ask the experts if there is any way to limit the particles generated by GPS to the radioactive seeds I designed. Thank you for your guidance and answers. As a newcomer, I really need your help

I also found a problem that the program worked when I used GPS to define a point source that emitted only one particle at a time. But when I hit five particles the program will also be killed. I really don’t know why this problem occurs. I look forward to your good advice and wish you a happy life.