What sort of contributions could a dying man make to science?

I was searching around for information on body cell replacement and stumbled on this thread, where I found this unrelated but intriguing quote:

This got me to thinking… supposing a hypothetical dying man with, shall we say, about 6-12 months left to live (perhaps more or less if that would affect the type of experiments that are performable), and assuming he is sane and rational but decides he wants to donate the remainder of his existence to furthering science or medical research, even at the cost of a further reduced lifespan, what sort of experiments could he (legally) volunteer himself for that would not be able to be performed on a non-terminal patient due to safety, moral, ethical, etc concerns?

I’d like to avoid the obvious answer of experimental treatments designed specifically for the ailment our patient is suffering, if possible. While no doubt equally noble and potentially beneficial to society, what I’m really curious about is what sort of gaps we have in our understandings of biology or physiology that could be better explored if only there were an ethically acceptable way for a person to volunteer his own mortality.

It’s totally a WAG, but we had a similar situation with my great-uncle; I think one cutoff would have been any test which involved direct, short-term harm. For example, no “causing a brain lesion to study how does it heal.” OTOH, if he happened to have a brain lesion, using methods to study it which would normally not be acceptable due to causing harm in the long term (like the example in the OP) would be acceptable.

The worst problem might be convincing the Ethics Committee fast enough. In my uncle’s case, he was a doctor and still is a legend among local medics almost 20 years after his death, so it wasn’t as difficult as with a regular patient; the convincing had to be double, both to run more tests than usual in order to follow the cancer’s progression and in order to not give him a lot of the usual medication (in his own words, he didn’t want to take anything whose main purpose would be to make his doctors feel like they “had tried everything”).

One guy who got an artificial heart said he did it to help others, he knew it probably would not help him live much longer. Doctors told him without the artificial heart he would die in a few weeks, he ended up living a few more months.

poison and poison gas research? When Russians (under Stalin), Japanese and North Koreans studied this stuff, they just used normal people. Maybe the dying are not quite normal, but you can get at least some info. Would this info be any more interesting than testing on pigs? No idea.

What happens to the HIV virus or leprosy bacteria in newly infected person within the first several weeks after immediate treatment with yet another potential wonder drug?

Drugs that mess with synapse growth in the brain, such as in order to make people smarter? All the more so if they have an immediate measurable effect but that effect can only be studied by taking the brain out…

While there might be many potential applications, I suspect that few would be cost-effective. Maybe something like HIV or leprosy research I mentioned above would be more useful than average because this stuff is hard or impossible to inoculate to animals. Meanwhile, what can be done on rats and pigs should be done on rats and pigs since they are cheap, plentiful and easy to work with.