These rules are courtesy Stuart Hall, currently a medical student at Baylor College of Medicine. This was adapted from Harrison's Principals of Internal Medicine, 13th Ed. (McGraw-Hill Health Professions Division). This is in no way a medical opinion and is somewhat simplified. If you any comments, criticisms, or corrections, send them to me. Send complimens, money, etc... to Stuart.
| 1 rad | the absorption of 100 ergs of energy in 1 g of tissue |
| 1 rem | rad
× RBE (Relative Biological Effectiveness) 1 rad of gamma-ray exposure = approx. 1 rem 1 rad of neutron particle exposure = approx. 20 rem |
Rad and rem are passe. They have been replaced by Gray (Gy) and Sievert (Sv). 1 Gy = 100 rad; 1 Sv = 100 rem
The damage of radiation is, of course, a direct result of the ionization of tissues as the radiation is absorbed. There are two classes of radiation: ionizing and non-ionizing. We lump the ionizing radiation into two classes: high-frequency electromagnetic waves of relatively short wavelength, and subatomic particles. high-frequency electromagnetic waves of relatively short wavelength are things like gamma rays, or machine-made x-rays. They penetrate deeply, and can ionize structures and thereby disrupt biologic processes as they pass through. Subatomic particles are nasty, because they densely ionize structures as they punch holes (figuratively) through you. They ionize everything, and create reactive free radicals and the like. The worst is perhaps the neutron, which can penetrate more deeply than its charged cousins. They interact with nuclei and release alpha particles, etc., in effect multiplying their destructive force. Long-wavelength non- ionizing waves, like infrared, ultraviolet, radio, and stuff affect cellular processes on a higher level. They interfere with things like RNA and DNA transcription and repair. But that's boring.
One thing I noticed with regard to radiation injury in the context of GURPS is that their chart is a little out of whack. 50 Gy (5000 rads) will certainly kill you, even with "treatment." But, persons with exposures of anywhere from 10 Gy - 50 Gy (1000 to 5000 rads) "almost always" die within 3-4 days. If you were exposed to 15 Gy, and you lived a week, people would be writing you up.
Note: Stuart is referring to the tables from GURPS Space. Compendium II has much more accurate tables (these tables n turn, come from GURPS Grimoire)
The early manifestations of acute exposure to excessive radiation are termed the acute radiation syndrome, which classically has four stages in those who survive the whole thing.
The onset and duration of these phases vary with the variables of exposure.
People with exposures of 50 Gy or more invariably die within 24-48 hours from complications of the neurovascular syndrome. This is characterized by a rapid onset of apathy, lethargy, and prostration. If that weren't enough, they then usually have seizures which range from random muscle contractions to generalized tonic-clonic (grand mal) . . . which end in ataxia and death. If there is early neurologic involvement, there is also usually a cardiovascular syndrome, which is characterized by severe blood pressure depression, cardiac arrhythmias, and shock before the patient dies.
In patients exposed to radiation in doses of 10 - 50 Gy, there is often a prodrome, then a latent period of a few days, after which a gastrointestinal syndrome follows. This is the result of ulceration, infection, and hemorrhage due to direct damage to the GI tract (mucosal atrophy) and bone marrow depression. It is associated clinically with massive fluid, protein, and electrolyte loss, and patients usually die within a few days of onset of symptoms. As I mentioned before, the wording in my text is "Death almost always supervenes within a few more days."
Patients exposed to doses of 2 - 10 Gy suffer the bone marrow syndrome. They have a prodromal illness for a day or so, then a latent period for a few weeks. They have a horrible course, which includes hemorrhage, ulceration you-name- where, and infection (due to their lack of white cells and platelets). Few survive. Those who do experience epilation (hair loss) after about a week or two which peaks at about two months. It can take a year for the hair to grow back.
Persons with exposure to less than 2 Gy rarely suffer from more than mild GI symptoms. However, since any significant exposure to radiation depresses the bone marrow, they CAN have problems with hemorrhage and infection.
I won't get into intermediate- and long-term effects. They consist of nearly any kind of malignancy you could name.
Treatment . . . well, for ionizing radiation, there is no specific treatment. The only specific agent in use is potassium iodide, given to patients who are exposed to nuclear fallout. It's not used as a chelator per se; it is given in excess to prevent the thyroid from taking up radioactive iodide. Researchers are currently looking into the use of chelated metals, not really chelating "agents," but they're a long way from having human applications. I did a recent Medline literature search and was unable to find any recent papers on the subject. I did find one from 1995 which suggests using essential metalloelement chelates to prevent radiation damage in mice.
The basic treatment is to decontaminate and monitor for surface contamination. I guess with kids, you could have a phony Geiger counter rigged up to go nuts near the "exposed" kids. They'd need to be hosed down, and their close decontaminated. If there's a dosimeter present, use it to determine the dose received. In the absence of that, there are certain damaged biologic markers that can be sought in a blood sample. The rest of the treatment is supportive, and, in the case of anything more than 2 Gy, GM-CSF (granulocyte-macrophage colony stimulating factor, to prompt the marrow to make white cells) and transfusions are used. Most of such patients would end up needing a bone marrow transplant.
Prognosis is variable. There is almost zero mortality with no treatment at doses of 1 Gy or less (100 rad). Mortality is nearly 100% at any dose greater than 15 Gy (1500 rad). A 50% mortality is expected without treatment in exposures of 2 - 3 Gy; with optimal support, at a dose of 4.5 Gy your chances of survival are 50-50. At 7 - 10 Gy, you can survive WITH a bone marrow transplant . . . assuming you could get a match within a few weeks (when a match usually takes months). At anything above about 12 Gy, there is so much tissue damage that there is really nothing that can be done.
Keep in mind, also, that these prognostic data assume that there is NO radiation (thermal or otherwise) burn, no trauma, and no underlying illness. Prognosis is significantly worse if there are concomitant conditions.
I hope this gives you an idea of what we can and can't do. The GURPS chart is a little off, and could use some revision. There's not really a treatment for overdose; I think giving the kids mineral water is a little misleading in that it propagates the myth that there is a pill you can take. From what I have read, taking anything (like KI) by mouth would only be helpful if you ate a radon hamburger. For occupational exposures (or just whole- body exposures in general), the most important thing is surface decontamination. I guess, if you were going to give anything, you'd give a cathartic and an enema (make them vomit and, well, you know about enemas). But there's not much to do but watch their blood counts.
The last paragraph refers to a simulation of radiation damage for kids. As you might have noticed, there isn't a nice way to do this...