|Fig. 1: Model of a nuclear-powered heart pacemaker developed by ARCO. (Courtesy of the DOE. Source: Wikimedia Commons)|
While nuclear energy and technology are known to have made significant strides in many different fields, an often overlooked one is that of medicine, most specifically medical devices. In the late 60's and early 70's, the idea of bringing nuclear batteries into the pacing industry was first introduced and ultimately pursued as by 1973, several pacemaker manufacturers had introduced nuclear models. The thought-process behind these nuclear pacemakers came down to longevity. They provided young patients the opportunity to have one pacemaker last their entire life. These nuclear pacemakers also proved cost-effective in comparison to the lithium battery powered pacemakers of today as follow-up costs of the two are roughly $19,000 versus $55,000 respectively.  Ultimately, the implementation of nuclear pacemakers came to a halt in the mid 1980's as lithium-powered pacemakers containing new technology and a more feasible life-span took over the market.
In looking at the nuclear pacemaker, there are two distinct kinds that became relevant in the short period of time that these medical devices were in use. The thermoelectric generator used Pu-238. Due to the extremely high risk and toxicity involved with using plutonium, numerous layers and shields were woven into these pacemakers resulting in larger and heavier devices. Despite strong concern of radiation exposure, the actual risk of exposure from these plutonium-powered pacemakers was almost non-existent.
Around the same time, other manufacturers developed a different nuclear cell for pacemakers utilizing the isotope Pm-147. Again though, due to the potential dangers of using these radioactive isotopes, extra precautions were taken in the physical development of the pacemaker resulting in a bulkier and heavier model.
Despite the often longer life-expectancies, nuclear pacemakers quickly became a part of the past when lithium batteries were developed. Not only did the technology improve, allowing for lighter, smaller, and programmable pacemakers, but doctors began to realize that this excessive longevity of nuclear pacemakers was excessive. Lithium pacemakers often last 10-15 years allowing for doctors to check in on their patients and replace either the batteries or the pacemakers themselves with new and improved technology as it is develops in those 10-15 year spans.  While there are still several remaining patients with nuclear-powered pacemakers functioning in their bodies, it is likely that in the next few decades as these patients pass away, so will the once promising nuclear pacemakers.
© Matthew DeGraw. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 G. Emery, "Nuclear Pacemaker Sill Energized After 34 Years," Reuters, 19 Dec 07.