In this study, we present a significant improvement in the minimum detection limit (MDL) for strontium measurement in bone
with X-ray fluorescence using 125I as the excitation source. The improvement was achieved thanks to a new collimator in the 90 degree geometry and a different
source positioning in the 180 degree geometry. The achieved MDL in the 90 degree geometry is 0.0426±0.0006 mg Sr/g Ca, which
is 5.5 times better than the one previously reported. In the 180 degree geometry, the new source positioning improved the
MDL from 0.118±0.004 to 0.0446±0.0009 mg Sr/g Ca.