Fix output filename formatting
Fix output filename formatting

alexkernphysiker/j-pet-framework,wkrzemien/j-pet-framework,JPETTomography/j-pet-framework,wkrzemien/j-pet-framework,JPETTomography/j-pet-framework,alexkernphysiker/j-pet-framework,alexkernphysiker/j-pet-framework,wkrzemien/j-pet-framework,JPETTomography/j-pet-framework,alexkernphysiker/j-pet-framework,wkrzemien/j-pet-framework,wkrzemien/j-pet-framework,alexkernphysiker/j-pet-framework