After the scan. Is there any mass left after interactions?

No - positron and electron annihilate each other, generating two gamma photons.

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Originally Posted by ebaines

No - positron and electron annihilate each other, generating two gamma photons.

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If annihilation produces E=mc^2 why does the body not explode?

Do the math:

, where m = mass of positron + mass of electron



So the energy of a positron-electron annihiliation is minuscule.

Quote:

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Originally Posted by ebaines

Do the math:

, where m = mass of positron + mass of electron



So the energy of a positron-electron annihiliation is miniscule.

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Since there are millios of annihilations why do we no see the sum(E)?
Sum(E) may not be explosive; but what about collateral thermal damage?

Even if there were 100 million annihilations the total energy released would only be 1.6x10^-5 J or 16 microjoules. This is still a minuscule amount. Given that the specific heat of water is 4.2 joules per gram per degree C and assuming that all the energy was concentrated in 1 milligram of water ( in reality it's all over the body) it would only raise the temperature of that milligram of water by about 4thousandths of a degree C. Definitely no thermal damage occurring

Quote:

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Originally Posted by elscarta

Even if there were 100 million annihilations the total energy released would only be 1.6x10^-5 J or 16 microjoules. This is still a minuscule amount. Given that the specific heat of water is 4.2 joules per gram per degree C and assuming that all the energy was concentrated in 1 milligram of water ( in reality it's all over the body) it would only raise the temperature of that milligram of water by about 4thousandths of a degree C. Definitely no thermal damage occurring

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Thanks