And again the story of how people used radioactive objects until they realized they were killing them.
It's a pacemaker. Over the years, various power sources have been used for pacemakers, including thermoelectric batteries containing 2 to 4 curies of plutonium-238 – that is, that plutonium called "weapons grade". As the term "thermoelectric" implies, the heat from decomposing plutonium is used to generate electricity that stimulates the heart.
There are currently between 50 and 100 people in the US with nuclear-powered pacemakers. When one of these people dies, it is assumed that the pacemaker will be removed and sent to Los Alamos, where the plutonium will be extracted. The pacemaker shown in these Medtronic production photos has plutonium removed. And as you can see in these photos, the electronics of the device are embedded in epoxy resin. And the solid titanium body is designed to withstand any incredible event, including a direct bullet hit and cremation.