Some thing wrong about the output in PET and SPECT

Dear CASToR user,

I am using Gate for PET and SPECT simulation,but the result looks like little strange.
Here is my phantom I used,the value of white part is 10, the red one is 1 ,and the black is 0.


Here is my reconstruction of PET and SPECT:


It seems that this is not a problem with running commands.Has anyone ever encountered similar problems in the use process.