And so, if you look at the pictures, you&#x27;ll see an interesting number denoting the quantity of plutonium powering the device. It&#x27;s not measured in grams, or even micrograms, or any unit of mass, as would be common with ordinary materials. Instead, the quantity of plutonium is measured in curies.<p>And is there a means of converting curies to mass?<p>Well, sort of... except radioactive decay generally means the original mass of a sample of material has been steadily converting itself into something else over time, so to provide a measurement of mass might not be a practical piece of information later on, and given the application in these circumstances, the gross weight of the device is more relevant than the mass of the plutonium therein, and the power provided by the plutonium, and how hot the slug is, turns out to be the more interesting number.<p>So what&#x27;s a curie?<p><pre><code>  The term &quot;specific activity&quot; is defined as the amount 
  of radioactivity - or the decay rate - of a particular 
  radionuclide per unit mass of the radionuclide. For 
  example, the specific activity of Ra-226 is 1, meaning 
  that one gram of Ra-226 contains one (1) curie (assumed 
  to be uniformly distributed throughout that mass)

  http:&#x2F;&#x2F;www.iem-inc.com&#x2F;information&#x2F;tools&#x2F;specific-activities
</code></pre>
And, so based on all those pictures, the devices seem to average ~2.0 to ~4.3 curies of plutonium.<p>The specific radioactivity of plutonium, according to the above source, is:<p><pre><code>  Pu-238 - 1.7E1
</code></pre>
So, approximately one or two grams per device.<p>Based on all this information, I bet harvesting plutonium pacemakers would be way more lucrative than stealing kidneys.