Cesium 137 is a lot less radioactive, it has a half life of about 30 years. As far as I know, it doesn't have a special affinity for a specific organ or tissue
Cesium is in the same grouping on the periodic chart (1A) as sodium and potassium and therefore could be found anywhere those two elements (or their salts) are found. In other words, just about everywhere.
It has been a while for me, but I do recall Cs-137 is very dangerous when inhaled or ingested. That was the case in South America when some people found a discarded medical source in a dump and broke it open to see what was inside.