I think this subject is worth revisiting every year or so, as many of us have sporadic needs for CT scans. I have one coming up myself in a couple weeks, hence this post. I've outlined what I think I know below, and invite your commentary.
It goes without saying that most doctors want maximum imaging resolution and just assume that it's acceptable to turn you into a neutron star in order to obtain that. Depending on the imaging requirements, MRI may offer comparable quality with zero radiation hazard -- in particular, 3T or better MRI with an appropriate contrast agent (if vascularization is relevant). Just make sure to research the kidney protection protocol required for that agent.
If CT is a necessity, for example for bone imaging, then see if a dedicated scanner can shave off some rads, for example, cone beam CT in dental and jaw applications.
I read somewhere that drinking a large amount of water prior to the scan can cut the radiation dose received, presumably because hydrogen is a radiation absorber, but I can't find any good references to this. Instead, I only see references to water with respect to kidney protection from CT contrast agents, as with MRI.
Absent any long term studies on CT scan dosage vs. cancer rates, you should at least have a look at this cancer odds calculator.
Now, critically, what is the best prophylactic regimen against CT radiation damage?
A. Days, ideally a couple weeks, prior
1. Liposomal vitamin C, 1 g/d. We need to let it accummulate in the cytoplasm.
2. Astaxanthin, 4 mg/d. We need it to build up in the lipid bilayer.
3. Magnesium sulphate (citrate? glycinate?) and gamma tocopherol (vitamin E). The only study I could find involved intractably high doses, though.
4. Nigella sativa oil which protects against radiation but might contain hexane residues from extraction, so perhaps stick with the seeds (3X as much required, by mass, to obtain equivalent oil content).
B. 24 hours prior
Start fasting, except for the supplements listed below. This is because (fasting-induced) ketosis preferentially enhances damage to glycolytic cancer cells. And you thought CT scans were all bad news! As a somewhat effective alternative, presumably a tablespoon of MCT oil or even coconut oil an hour before the scan should raise blood ketones, albeit not to the level of a day's fasting.
C. An hour minutes prior to the appointment (maybe 75 prior to the scan itself)
1. 4000 IU vitamin D (based on its purported antiradiation benefits, for which I can find no evidence apart from UV).
2. 15 mg c60oo (essentially 20 mL of oil). More might be better, but this is roughly the maximum single dose which is well documented on Longecity.
3. 500 mg niacin. This upregulates NAD+, which should help with DNA repair after the fact. (Might it protect damaged cells, though, which would be bad?)
4. 1 g nicotinamide riboside. This upregulates NAD+ through a pathway parallel to niacin (so the same question applies).
5. 200 mg of pterostilbene, or more if you can handle the hypoglycemic effects. Like vitamin D, it lessens UVB damage so I'm optimistically extrapolating to radiation damage in general. (I think the pathway might be the same, as I recall that its cousin, resveratrol, interacts with vitamin D receptors.)
6. 1 mg of melatonin (but don't fall asleep on the way home!). This amplifies the damage to some cancer cells but might reduce damage to normal ones.
7. 5 g of Longvida or some other lipidated curcumin because curcumin is rumored to act bivalently, like melatonin, and we want to lipidate it to enhance uptake.
8. 100 g dark chocolate, the darker the better. (An organic cacao drink might be preferable, if less convenient, because it would be less disruptive to ketosis.) Chocolate is rich in epicatechin, which protects against DNA strand breaks and enhances cancer cell susceptibility to radiation -- yet another bivalent agent.
Finally, comments have been made on Longecity previously to the effect that radiation-induced hormesis might be a good thing. I would have to agree, considering that hormesis apparently results from every toxic compound, given sufficiently tiny exposure. But from an evolutionary standpoint, it seems to me that the hormesis benefits would only occur on the level of moderate UV exposure, which is orders of magnitude less radiation than any CT scan.
Edited by resveratrol_guy, 16 October 2015 - 10:52 AM.
The actual risk of a fatal cancer from a CT scan is perhaps 1 in 1,000 or 1 in 2,000. The chances of dying in a car crash on a given trip are less than one in a million.
