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Plutonium Powered Pacemaker (From 1974)

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Re: Plutonium Powered Pacemaker (From 1974)

#21

Post by stinkbeetle »

kondro wrote: post #4
stinkbeetle wrote: post #3

Earlier quoted context omitted.

> For context, the 0.1 rem yearly dose to the patient is about 1/6th of the average background dose we all get every year. Wouldn't you be more concerned about dose rates in tissues near the device though, rather than whole body dose? At the surface of the pacemaker it would be about 90 rem / year.

REM is already an adjusted measure for absorption, not an general quantity of radiation.

This doesn't address my question. OP was talking about the whole-body dose, I'm asking about the surface and nearby dose.

Re: Plutonium Powered Pacemaker (From 1974)

#22

Post by stinkbeetle »

BurningFrog wrote: post #16
stinkbeetle wrote: post #3

Earlier quoted context omitted.

> For context, the 0.1 rem yearly dose to the patient is about 1/6th of the average background dose we all get every year. Wouldn't you be more concerned about dose rates in tissues near the device though, rather than whole body dose? At the surface of the pacemaker it would be about 90 rem / year.

Since it's a device that saves the life of the patient, you can accept a lot of patient risk as a tradeoff.

Obviously. That doesn't address my question though, the dose of concern is surely the nearby tissue rather than one calculated over the whole body. If the pacemaker is resting against my lungs, I'm not going to be concerned about foot cancer.

I'm not implying the risk was miscalculated in the medical approval process, I'm sure it's safe enough. I'm just questioning OP's statement about radiation dose, yes it's strictly true but seems to underplay the importance of the nature of the dose.

Re: Plutonium Powered Pacemaker (From 1974)

#23

Post by stinkbeetle »

LeoPanthera wrote: post #20
stinkbeetle wrote: post #3

Earlier quoted context omitted.

> For context, the 0.1 rem yearly dose to the patient is about 1/6th of the average background dose we all get every year. Wouldn't you be more concerned about dose rates in tissues near the device though, rather than whole body dose? At the surface of the pacemaker it would be about 90 rem / year.

[flagged]

I definitely read that part of the article, how else do you think I came up with that 90 rem / year number??

That does does not "cover" my question though. Perhaps you didn't actually read or comprehend my question? I was wondering whether the radiation dose rates for tissue near the device is more concerning than the whole body dose. This might seem fairly obvious, but I'm no medical expert (and either way it's still not covered by the article). And it is intended to be read in the context in which it was asked.

Glad I could help clear that up for you, you're welcome.

Re: Plutonium Powered Pacemaker (From 1974)

#24

Post by stinkbeetle »

SoftTalker wrote: post #5
stinkbeetle wrote: post #3

Earlier quoted context omitted.

> For context, the 0.1 rem yearly dose to the patient is about 1/6th of the average background dose we all get every year. Wouldn't you be more concerned about dose rates in tissues near the device though, rather than whole body dose? At the surface of the pacemaker it would be about 90 rem / year.

Pu-238 decays mainly by alpha decay which would be easily contained by the titanium casing.

Thanks. Presumably we're talking about "Dose rates at the surface of the pacemaker are approximately 5 to 15 mrem per hour from the emitted gamma rays and neutrons" though.

Re: Plutonium Powered Pacemaker (From 1974)

#25

Post by cyberax »

SoftTalker wrote: post #5
stinkbeetle wrote: post #3

Earlier quoted context omitted.

> For context, the 0.1 rem yearly dose to the patient is about 1/6th of the average background dose we all get every year. Wouldn't you be more concerned about dose rates in tissues near the device though, rather than whole body dose? At the surface of the pacemaker it would be about 90 rem / year.

Pu-238 decays mainly by alpha decay which would be easily contained by the titanium casing.

It also spontaneously fissions, with daughter products often being gamma/beta active. And it always contains some contaminants

Re: Plutonium Powered Pacemaker (From 1974)

#26

Post by cyberax »

jandrewrogers wrote: post #8

> Dose rates at the surface of the pacemaker are approximately 5 to 15 mrem per hour from the emitted gamma rays and neutrons. Where are these gamma rays and neutrons coming from? The decay chain for Pu-238 is via alpha emission (Pu-238 -> U-234 -> Th-230 -> ...) which won't penetrate the casing.

All U and Pu isotopes undergo spontaneous fission, producing neutrons and random daughter products.

Re: Plutonium Powered Pacemaker (From 1974)

#27

Post by sanarothe »

For similar / further reading on historical pacemakers, check out https://www.implantable-device.com/category/implantable-comp... where David Prutchi has amassed what I think is a comprehensive history of pacemakers / neurostimulators ranging from these early atomic designs up through current day devices / companies.

Re: Plutonium Powered Pacemaker (From 1974)

#28

Post by stinkbeetle »

jmb99 wrote: post #18
stinkbeetle wrote: post #3

Earlier quoted context omitted.

> For context, the 0.1 rem yearly dose to the patient is about 1/6th of the average background dose we all get every year. Wouldn't you be more concerned about dose rates in tissues near the device though, rather than whole body dose? At the surface of the pacemaker it would be about 90 rem / year.

If I die without a pacemaker, or maybe have an increased risk of certain cancers with a pacemaker but get to live, I’d choose the pacemaker.

Duly noted.

Re: Plutonium Powered Pacemaker (From 1974)

#30

Post by SoftTalker »

stinkbeetle wrote: post #24
SoftTalker wrote: post #5

Earlier quoted context omitted.

Pu-238 decays mainly by alpha decay which would be easily contained by the titanium casing.

Thanks. Presumably we're talking about "Dose rates at the surface of the pacemaker are approximately 5 to 15 mrem per hour from the emitted gamma rays and neutrons" though.

Yeah ideally I would not want that in or close to my body but if the choice is literally life or death I guess I'll take it.

How do modern pacemakers work? Can they be recharged inductively or is surgery required to replace batteries periodically?

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