Safety - Radiation Exposure
Usually, high-dosage exposures cause symptoms to develop immediately,
and low dose exposures have delayed effects. The
somatic and genetic effects
regarding low-dose exposure have been described.
High-dose Radiation Exposures
From the experiences in industrial and laboratory accidents, atomic bomb
explosion in Hiroshima and Nagasaki, atomic and thermonuclear testing
grounds, and miscalculated and accidental medical exposures of patients,
we have learned the consequences of high-dose radiation exposures.
Injuries due to radiation in the past led the medical profession to
divide the radiation clinical cases into four categories.
From these categories, we learn to appreciate the level of danger
when a whole-body is exposed to various doses.
Effects on Human systems:
- Low dosage - less than 1 sv (100 rem)
Patients under radiological treatments with a one-time whole-body exposure
of 14-100 rem showed no particular radiation syndromes and they all
recovered well. Few cases showed nausea and vomit. Symptoms and harmful
effects vary due to different health conditions of individuals. Data
for delayed effects are not reliable..
- Medium low dosage - 1-2 sv (100 - 200 rem)
Victims receiving 100-200 rem showed nausea and occasional vomiting
on the day of exposure or the day after. Itching and burning were
felt in the skin after exposure, and these sensations subsided in
few days. Two weeks later, however, dermatitis (skin inflammation),
itching, burning and pain were severe. More serious ones showed
epilation (loss of hair), erythema (abnormal redness due to
inflamation), necrosis (tissue death), wet desquamation (peel off),
followed by weeping, crusting and ulceration (open sore). Some cases
recovered if infections were prevented by medical treatment.
- Medium high dosage exposure 2-5 sv (200-450 rem)
All victims receiving 200-450 rem showed anorexia (loss of appitite),
fatigue, nausea and vomiting, some had diarrhea. These symptoms might
persist for months, but some may show signs of recovery. However, the
patients in this group were susceptible to infection. Hemorrhage
(discharge of blood) in various tissues may happen, and chances of
recovery are limited to only a few.
- High dosage exposure more than 5 sv (500 rem and more)
The human lethal dose (LD50) is generally believed to be 400 to 500 rem,
lower if the dose is received in a short time period. Clinically, survival
for victims who had received more than 500 rem was impossible.
Higher doses had resulted in quick death. Victims would go through
stages of disorientation and shock due to injury to central nervous
(CN) and cardiovascular systems. On the other hand, some victims
overcome infections and they survived after bone marrow transplant.