Table 8 Summary of Svscem Efficiency and MDLS for Field WBC Svstem Nuc lide fi Enerev Efficiency MDL Time 1a 662 Kev 8.7 x 1079 37 Bq (1 nCi) 900 sec 6065 1173 & 1334 Kev 6.7 x 107? 37 Bq (1 nCi) 900 sec 40, 1460 XeV 7.0 x 107° 222 8q (6 nCi) 900 sec