Nuclear-Powered Cardiac Pacemakers
osrp.lanl.gov
osrp.lanl.gov
Thus begins one of my favorite Ian Banks novels, starting with exactly this event.
That all is significantly more expensive than saying "you hand us a form telling us whether there's a pacemaker or not, and if you fuck it up you get in trouble."
Fair point on suing people probably being cheaper, though. -.-
Would you have to remove the joints as well then? How are you meant to properly dispose of something like a knee or a hip?
WTF!?! We have plutonium powered pacemakers?
http://large.stanford.edu/courses/2015/ph241/degraw2/
Ah, okay we had.
> 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.
I cynically read this as "we needed to get more money out of these patients"
Additionally, any kind of implanted device is significantly prone to a wide range of problems that range from inconvenient to devastating. The human body is very hostile to foreign objects, often with few warning signs. Clots and fibrous capsules (and eventually, calcified capsules) form around ANY implant, and that's the best case problem.
Titanium is extremely biocompatible. It forms a thinner capsule than most materials. It integrates with bones beautifully, due to surface treatments that allow bone to grow into microscopic surface cavities, with strong molecular bonds. But also sometimes, for no apparent reason, all the bone around a titanium implant will just start dying and resorbing. It's rare, but if you get a hip replacement you absolutely need to check on it regularly because if you don't you'll lose use of the leg completely (and quickly, and permanently).
In and around the heart is one of the most challenging places to implant things, aside from maybe the brain. Any moving part of the body will constantly stress any mechanical part, and build up scar tissue around and rubbing spots. The only reason the brain is worse is because its fragile and changes size significantly when you sleep.
Recently we started using leadless pacemakers. Even before that pacemakers were continually getting smaller, and smaller pacemakers are less irritating and experience less stress and movement. Even if that weren't true, it would still be worth checking in on pacemakers, because they're doing incredibly hard jobs and if they fail people can die faster than they can get to a hospital.
EDIT: oh, and heart disease is the #1 cause of death in the US, while heart surgery is one of the most difficult specialties to get in to. They are absolutely never short on patients, lol.
Maybe my cardiologist is just trying to make me feel good, but he says my leads will likely last 30-50 years. Intuitively that seems unlikely, but we'll see. It's got to be one of the most engineered cables in existence.
The leadless pacemakers are indeed a technical marvel, but they aren't yet nearly as feature packed as shoulder implanted devices. They'll keep your heart from stopping if your nerves are flaky from time to time, but they don't have the energy storage to do much more than that. Mine monitors every single beat my heart takes, and automatically reports issues to my doctor via BLE. (Is bluetooth more or less scary than radioactive isotopes mounted in your body?)
For about 8 months, my AV nerves were completely broken, and the pacemaker paced my ventricles 100% of the time. It was a nearly perfect drop-in replacement for the failed nerves. A leadless pacemaker wouldn't have had nearly the same performance. My nerves eventually started mostly working again, and now I'm on track to have a battery life pushing 15 years.
It would of course be great for the technology to advance even more over the next decade. Since my nerves mostly healed, a leadless device with a 30+ year battery life would be a nice replacement. With a shorter battery life, I don't really want to be collecting them in my heart (they don't plan to remove leadless pacemakers when they die.) I'm hoping by the time my current device is worn out, it will have logged enough telemetry for me to convince my cardiologist that I don't need a pacemaker at all, though.
One of my favorite learnings in school was about the "Endurance limit".
Some materials, like aluminum, will eventually fail under cyclic loading even at tiny, tiny loads. This was a big problem when they built the first passenger jets. Other materials, like steel, have a threshold at which they can be cycled indefinitely without issue.
For something like a pacemaker, I like to imagine they dialed the materials and forces to be within such a threshold so you can keep on ticking!
What I want is a shoulder implanted pacemaker that's significantly smaller, with a quarter of the primary battery capacity, and an inductively charged supercap that can store enough charge to run at least week between charges.
BLE replaces the previous diagnostic interface, which was some form of near-field. You had to have a puck resting within a few inches, going to a several decade old toughbook. My device supports both. It's just in the last couple years that UCLA got the BLE equipment, and sometimes a doctor will whip out the old gear if they feel more confident with it.
When I had the pacemaker first implanted, there was a reliability problem they had to do a second operation to fix it. The pacemaker failed to "capture" my ventricle a few times when it should have. It turned out to be a loose lead connection, but the device's impedance diagnostics didn't make the issue immediately obvious. My overall case was weird enough that UCLA did a case study about it, so for the revision procedure they had a vendor rep in the room to help out just in case. She was holding a tablet and pushing buttons that would make my heart temporarily stop.
Now my AV nerves mostly work again, so the pacemaker can't stop my heart if it wanted to. It can only increase my heart rate, and report unusual patterns to my doctor. Also, if someone did somehow mess with it, holding a strong magnet near it will force it into safe mode.
You would think if you can detect a strong magnet, you could use that to turn the wireless on and off... Like how holding a power button on a phone turns it off, but holding longer can do a factory reset or what have you.
Glad you're doing better since then, though.
eliminating RF/BLE bullshit from talking to the pacemaker.
-
Oops - I didnt realize you were same poster from other comment
If you got in you could probably put the leads into single-ended mode (so that there's more current path to cause mayhem) and pace my atrium and ventricles at 210bpm, and effectively give me a seizure. I can't imagine it would kill me before an EMS arrived with a magnet?
Perhaps a more nuanced attack would be to somehow use all the configuration parameters to intentionally bias the pulses so that there's net charge going into the muscle. Over a long time that would cause tissue damage.
If someone wanted to kill me overtly, a gun would be less work. A pacemaker malfunction that bad would be thoroughly investigated, and would be fixed in new devices within a year or two.
Perhaps, he got the 'reverse bounty' on this bug...
Nah, it's not that bad. Decent mechanical keyboard switch is specified for 100 million clicks [1, or google for "switch million actuations"]. Surely good engineering can eek out another order of magnitude. Not to mention - pacemaker leads ("wires"), the only part that bends, have way less stress on them (= larger bend radius) compared to a keyboard switch. Oh, and technology of multi-strand wire for redundancy is a very well established and understood one.
[1] https://cdn-shop.adafruit.com/product-files/4974/EN_CHERRY_M...
I'm going to assume those failure numbers are far higher than you'd want for something keeping you alive.
The doctors keep quoting figures of how reliable this tech is, but I've had 3 procedures due to device failure in the last 5 years.
This is still relevant to his concern, but from the other end. They might be making the labor artificially scarce to increase pay.
This is very much true. I find that a lot of people in tech seem to put healthcare on a pedestal and believe that the professionalisation and gatekeeping of the industry create a better outcome than other engineering fields. This is very much untrue, the healthcare field is in need of massive disruption and lobbying to increase labor supply. You are being downvoted because a lot of tech people here hate to imagine that healthcare at the highest level is still subject to market forces like everything else. Medical training is being severely gatekept and hindered via the current apprenticeship/residency system. After all, we call the worst medical student, doctor. If you want to improve healthcare, tie medical school admission to the MCAT score, and only the MCAT score. You are not going to get better doctors just because candidates spend their summers building houses in some impoverished third world country.
I heard consistently that residency slots are extremely competitive and a lot of qualified candidates get passed over. The more I learn about the process the more insane it seems.
From the student perspective you go from paying to work one day and spending most your time working cases with zero relevance to your actual specialty, to raking in several hundred thousand a year.
It also seems like hospital systems seem to spend more than half their capacity either dealing with patients that don’t need to be there but there’s literally no place to send them, or patients that are too far gone and untreatable but there’s literally no place to send them.
Healthcare is like a Gordian knot of terrible policies cemented into place by trillions of dollars of government spending.
Heart surgeries often happen on actively beating hearts. Tiny mistakes mean death. Infections mean death. Its a muscle which never gets rest, the majority of people in the US have clogged arteries and high blood pressure by the time they die.
Theres no artificial shortage. Heart surgery is really hard. Its the third hardest kind of surgery, right behind brains and rockets.
Wait,what??
I agree that a surgeon at a general hospital probably wouldn’t care (little financial incentive).
The vast majority of pacemakers are placed by cardiologists with an additional two years of training in electrophysiology (not by cardiothoracic surgeons, who prefer to do complicated open heart surgeries and generally find things like pacemakers boring).
Contrary to the conspiratorial thinking all over this thread, medical society guidelines have scaled back the indications for putting in pacemakers time and time again, so the market has shrunk. Electrophysiologists have to make up for the lost pacemaker volume by doing newer procedures (ablations) that reimburse less per hour of work. Even then, the volume at a lot of shops isn't enough to merit full time work. A lot of graduating electrophysiologists have to take mixed electrophysiology/general cardiology jobs where less than 50% of the work is electrophysiology.
All that is to say, no, pacemakers are not a money making scheme. While there is decent money to be made, it's a shrinking market and those who got obscenely rich putting in pacemakers in the 80s and 90s have mostly already retired.
[0] When the pacemaker detected a problematic arrhythmia it would give a couple of defibrillation shocks just like the paddles but right on the heart muscle. He said this felt like getting kicked in the chest by a horse and came completely out of the blue with zero warning. So it could be quite disruptive. He wanted a feature where it would tingle or beep or something just a few seconds ahead of time so he could mentally prepare; apparently the second one that was expected was a lot less traumatic. Anyway, the docs thought it was a good idea, and passed it up, but it never happened before he passed.
reminds me of the pre-safe sound prior to collision
https://www.mercedesbenzofnatick.com/new-features-mercedes-b...
Heart problems are funky.
Most patients don’t survive those 10 years anyways.
My understanding is that people diagnosed with bradycardia young can expect to survive a long time with the device.
He died in 2014, not from heart-related issues.
I'd say that was a good return on medical investment.
We're all going to die and an extra 9 years is not bad.
I see people Dad's age or older driving and walking around and I find it amazing how older people are alive. Elderly people are amazing as people and for their knowledge.
Love every day you and your family are here and healthy!
> I personally could be realistically looking at 3 replacement devices and at least one lead replacement over the years. In the unlikely event that I suffer from ventricle enlargement long term, I'd need two more leads installed as well.
This is the point I'm making, though: realistically, you have a high chance of needing 2 additional procedures for non-battery reasons, which are likely good times to replace the device, too.
Unfortunately in the OECD I think its possie for an American to read it this way due to the unusual health system. Don't get me wrong... things are changing elsewhere too... it used to be a great shame to go sue a surgeon for anything but reckless intentional negligence... after all we all have bodies that age and decay and the surgeon is provided freely as a public service and their profession is to try as best and compassionately as they can with their training they recieved freely to delay or prevent the suffering inevitable from life... now people sue here for like an orthopetic surgury that simply didn't produce any result ... we are becoming more like america it is sad.
Same. In what world can a lifesaving device run excessively long? One with our health system is where...
What a strange phrase. I would say it was because of the concern of the risk of radiation, not "despite" it, leading to the precautions built into the device, that the risk was reduced to "almost non-existent".
Or is this a claim that the shielding was unnecessary?
Even though people might worry about radiation from the device, the actual risk (due to all the shielding) is almost non-existent.
Short summary: Soviet engineers installed RTG powered radio relays to support the construction of a damn in Georgia. Political instability lead to the abandonment of the RTGs. Someone scavenged the generators and removed the radioactive cores from them.
Two of the radioactive sources were discovered by men gathering firewood in the forest. They decided to bring them to their camp(!) and cozy up to them to keep warm during the night(!!). Despite showing symptoms of radiation poisoning they kept the cores on their person while loading their truck(!!!). They all suffered terrible radiation injuries.
There are more sources "lost" from the same batch which remains unaccounted for to this day.
https://m.imdb.com/title/tt1588875/
Only the Soviets were daft enough to build RTGs using Strontium 90.
The United States did too.
Oak Ridge National Laboratory technical report "Strontium-90 Heat Sources"
https://technicalreports.ornl.gov/1971/3445605716035.pdf
Introduction
Compact electrical generators powered by heat from radioisotopes have been under development in the United States since the early 1950s for space, marine, and terrestrial uses. Essentially all the generators developed for marine and terrestrial uses have been powered by 90 Sr. This report summarizes the development work done by Oak Ridge National Laboratory (ORNL), Hanford Atomic Products Operation, and Martin Company, Nuclear Division, which led to the production of 90 Sr heat sources for use in the generators.
It was a natural choice since strontium 90 is an inevitable byproduct of operating any fission reactor, and was readily available as a coproduct from weapons plutonium production reactors. Making better RTG isotopes like plutonium 238 required additional infrastructure.
I mean, Sr90 is super cheap, and as long as it stays inside the RTG you're fine. The AEC actually tried Polonium RTGs in the late 50s.
The shorter half-life of Sr compared to Pu also means it's a bit less of an issue when you lose the source.
https://www.emergencylights.net/collections/self-luminous?gc...
They aren’t generating electricity though.
These batteries have very poor power density and are very inefficient. The advantages of nuclear-powered batteries are:
- They generate power over a long time, decades,
- They generate some heat.
They don’t generate much power. If you have a building, you would definitely think of a nuclear RTG as a “very shitty battery”, and that’s even if you don’t care at all about radioactivity.
Thinking of these as a “battery” is also a bit misleading, IMO. These are really just small power plants, which generate heat and turn the heat into electricity. The heat is powered by radioactive decay of Pu-238, and then turned into electricity with the extremely inefficient Seebeck effect. If you had a source of heat you wanted to turn into electricity, it’s much more efficient to use that heat to turn a turbine which is connected to a generator. And if you want an efficient, cost-effictive turbine, you make it big. At that point, you have a power plant.
The beta decaying substance is connected electrically to one electrode of a capacitor, while the electrons emitted due to the beta decay are able to pass through the insulating layer of the capacitor, reaching the other electrode.
Thus the capacitor is charged directly by the beta-decay and it can provide electrical energy to the external circuit.
The problem is that a nuclear reactor is a dynamic system, with some moving parts. It requires thermal management. It requires dynamic control. It is really hard to design a fully self-contained nuclear power system which wouldn’t require any human intervention to operate.
And even if we could, there is also a problem of waste management. Nuclear waste is not too dangerous, if you don’t touch it. It is, however, quite dangerous, if you grind it into fine particles and spray a large city with it by a crop duster. Our world is crazy. There are people like that out there, who might be interested in it. It is relatively hard to obtain hot nuclear waste from centralized large power plants. It will be really easy in the case of small building-scale reactors.
We'd need to have a lot of money, a disregard for return of investment and a lot patience: Current RTGs can do that, but they're rather expensive for heating houses and problematic from the nuclear materials POV (waste / profileration), not to mention the regulatory and licensing for using it a neighbourhood - better budget the time and money for lobbying for some legislation changes.
If by building we mean say 10 apartments, and each needs 10 kW, the RTG would need hundreds of kg of Pu-238 plutonim dioxide [1].
It's hard to cite the exact cost for that since it's not a freely traded commodity but that's a lot of plutonium. Eg NASA said that with a $75-90 million investment they can make 1.5-2 kg per year of it. [2]
[1] https://drinksavvyinc.com/blog/how-much-does-a-radioisotope-... gives 2 kW per 5 kg [2] https://www.space.com/20774-plutonium-spacecraft-fuel-nasa-b...
The EneFarms used to be heavily subsidized by the japanese government in a long term program to encourage fuel cell development and manufacturing. Over time prices have decreased such that the subsidy is either already expired or could be soon expired.
The tech is near, and allows getting a bit more energy out if natural gas. The gas companies hope it will allow them to eventually reuse their pipes to send hydrogen. Personally I think the combo of cheap solar panels and 400% efficiency heat pumps will outcompete gas.
If heat pumps are 400% efficient then log burners in cabins in the woods are even better.
Thank you for helping me learn a new HVAC term!
It's desirable for multiple reasons, of course, but it's not efficiency.
The 400% metric let's you compare with other heaters, the 100% is kind of useless.
A heat pump takes heat from outside the system. You put in x fuel and you get >x heat. Getting more energy than you put in makes the efficiency over 100%.
Even manufacturers call this 'coefficient of performance', not efficiency.
> "You can't [...]"
He did, so obviously he can. You mean shouldn't, not can't.
If we're willing to be so blasé with 'efficiency' then why not, say, 'functional programming'? If it works it's functional right?
I think only matter-antimatter reaction comes close to 100%. Burning fuels isn't even 1% of that.
Small research reactors exist, but they tend to generate in the neighborhood of tens of watts.
Only really viable in deployments that need very little power, where no other energy harvesting method is available, and periodically changing out batteries is not an option.
Best that you not discover that little detail when you're trying to "seal the deal" with an ultra-powerful Eldritch Abomination, which you summoned from Far Beyond Mortal Realms, and are pulling the still-beating heart from your live human sacrifice for that kinda-critical part of the Horrific Ritual.
And it's clearly a detail which any Faithful Lieutenant should check when "procuring" sacrifice victims. And yet another reason for any survival-oriented members of the Evil Overlord's Legions of Terror to request postings in distant and sleepy bits of the EO's Empire - far from the glory and promotion opportunities...
On the one extreme, you have the Elephant Foot at Chernobyl, which even today will kill you if you, like, go up and lick it. But it's not going to sneak up behind you, so just don't go over there.
On the other extreme you have the release of radioactive water from Fukushima, which instantly dilutes to nothing in the vastness of the ocean. Meh.
In the middle, you have radiation sources like this, which are small enough to be unnoticed and highly mobile, but clumpy enough to still kill you dead if you get too close. Unless you have a radiation detector, you could step on one on your way home today and never know it.
Scary!
Stuff with a really short half life is horribly radioactive, but not for long. Stuff with a half life of millions of years sticks around forever, but it’s not throwing off that much radiation. But stuff in the middle (a half life of perhaps decades to a thousand years) can be very dangerous and remain that way for a long time.
Plus it can probably be done in roughly a headphone jack sized spot.
Nah... You will know it quite soon.
https://en.wikipedia.org/wiki/Ciudad_Ju%C3%A1rez_cobalt-60_c...
There were houses built of contaminated rebar! The story gets crazier the more you read about it.
A caesium-137 source from an industrial sensor has been lost and ended up inside a concrete wall of an apartment building; four people died from it.
Lia was two RTGs, which the URSS used quite a lot, and which regularly got lost or into accidents e.g. two degraded RTGs were found in the north of russia in 2003, one on the Cape of Navarin and one near Kola Bay, and two got dropped by a helo transporting them in 2004.
Though from the Plainly Difficult channel, I feel like the most frequent radiological accidents aren't even orphan sources but either misused / defective radiological devices (à la Therac 25), or commercial irradiation facilities whose opsec degrades until fatal exposure occurs after a jam.
https://www.upi.com/Archives/1984/04/02/Radioactive-tables-r...
Otherwise, Mexico (my country) being Mexico, I am sure nobody would have known anything about it. Specially during that time when we had a "soft dictatorship" that buried all bad things under the ground (not that nowadays is that much different...)
Anyway, thanks for the read, I have always found very interesting to know the extent of the contamination.
https://navajotimes.com/reznews/grand-canyon-gateway-chapter...
They've been begging the EPA for help for decades.
Is it “stealing” if it’s abandoned?
This whole thing was a complete failure of bureaucracy from that start and the only entities that deserve any blame are those responsible for leaving nuclear waste in an abandoned facility after being told about it.
The hospital moved to a new site but as there was disagreement with their previous landlord they were prevented to move equipments by the police despite trying to secure the source which was later stolen and having repeatedly warned of its danger.
I'd use a capacitor to accumulate a charge which would power one of the really old-school LED digital watches of the early 70s.
Totally impractical, dangerous and illegal? Sign me up!
There's not a miniature nuclear reactor in there, it's just a RTG, which is simple but also very inefficient. So it doesn't get the crazy amount of power from a tiny amount of material a fission reactor does.
I believe these are not RTGs (radioisotope thermoelectric generators.) Rather they use radiovoltaic conversion, probably alphavoltaic conversion judging by the use of Pu-238. Such devices convert alpha or beta radiation directly to electricity using semiconductors, not unlike photovoltaic cells.
But your point still holds, these atomic batteries produce a tiny amount of power.
Maybe it would make people put phones in the sun all the time and wear out batteries with heat.
No, it wouldn't. Sunlight is ~1 kW per m^2. A medium-sized room has maybe a couple 60 watt bulbs, spread over 10+ m^2, each of which radiates ~10 watts of actual light.
Light indoors is pretty easily 1000x less than outdoors. Eyes work exceptionally well in low light conditions, so we don't even realize the enormous difference in brightness.
If it's on for 8hrs a day and you capture all of it, on 1/5000th of a room, you get... 4mWh, or in reality, 0.7mWh because panels aren't perfect?
You could make a call in a few months of charge time. with a 3x3inch panel. But yeah, I suppose I was wrong and "eventually" is a bit of an understatement.
However I do not trust the public to dispose of recyclable waste properly, let alone radioactive devices.
I have had an iPhone 7 for many years; yes, same device. I don't remember the exact time when I got it, but it might've been around 2017. So this device is over 5, if not 6, years old. In all this time, I've had to replace only the screen due to physical damage, but the phone is otherwise perfectly functional. I've been told a few times that the battery needs replacement, but that's primarily because the phone reports battery's "Maximum Capacity" is 73%; but I'm reluctant to replace the battery because I haven't had any problems with the current battery.
Another data point: I bought an iPad Air 2 in November 2016 for my kids, and it's been used by my kids, changing hands as the older one grew out of it, and has had zero issues. Yes, it's screen has got scratches, and it's got blemishes on the body. But it's been running along just fine for over 7 years now. It's getting OS updates, even though it's been discontinued for over 5 years. I cannot say that for any of the Android devices I had bought, not even the ones made by Google.
Before getting the iPhone, I was firmly in the "android is best" camp, and I was almost against buying Apple devices, primarily for the cost of the hardware. I have bought phones, and a tablet, powered by Android, but none of them lasted long enough for me to extract value out of my investment. Either they died early because of some hardware failure, or because the device stopped getting updates.
After trying iPhone, and Apple's other hardware, like MacBooks, I have become a fan of the _quality_ of their products. Their products may not give the customer the same freedoms (of choice) and flexibilities that we've come to expect from Linux and Android worlds, but their products serve the needs of their customers for long durations, and in a way that no other company possesses the ability to do.
If you are of the type who pines for products of a bygone era where the products used to last decades, serving the customers faithfully without much fuss, I think you should seriously consider buying Apple devices.
From the site guidelines. The most plausible interpretation by far is that the comment referred to the time between charges; otherwise, what would nuclear power do to extend the lifespan of a device?
> Any chance we can get a nuclear-powered iPhone which lasts 4 years?
> iPhone that lasts 4 years
Sorry if that was not your intent.
https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/f...
Now my sibling comment links to a paper where they say they can find heat differences in the body that are sufficient for their needs, so this is still a possibility! But it does mean you need to be somewhere with a heat gradient: the paper mentions just under the skin.
But some satellites actually had real fission reactors on board. The US had the experimental SNAP-10A satellite and the soviets used a small fission reactor in their RORSAT satellites to power a radar so they can detect NATO naval fleets.