Tabla 3 Summary of Svstem Zfficiency and MDLS for Field WBC System Nuc lide 13705 C5 40 K Energy Efficiency MDL Time 662 KeV 8.7 x 1073 37 Ba (1 nCid 900 sec 37 Bq (1 nCi) 900 sec 222 Bq (6 nCi) 900 sec 1173 & 4 1334 KeV 6.7 x 10 1460 KeV 7.0 x 10 ~3