Types of Radiation Exposure: Acute, Chronic, and Prenatal Effects

Radiation exposure is categorized by dose rate and duration:

1. Acute Exposure

High dose, short time (minutes to days). Causes Acute Radiation Syndrome (ARS):

• Nausea, vomiting, diarrhea (hours).
• Skin burns, hair loss (days–weeks).
• Bone marrow suppression → infection, bleeding.
• High doses: multi-organ failure, death in days/weeks.

2. Chronic Exposure

Low dose, prolonged (years). Stochastic effects:

• Increased cancer risk (leukemia, thyroid, solid tumors).
• Cardiovascular disease, cataracts.
• Risk depends on cumulative dose, age, sex, genetics.

3. Prenatal Exposure

Radiation to pregnant woman affects fetus:

• Pre-implantation: usually lethal or no effect.
• Organogenesis (3–8 wks): malformations, growth restriction.
• Fetal period: CNS damage → intellectual disability, microcephaly.
• Childhood cancer risk increased at doses >100 mGy.

Radiation protection principles (time, distance, shielding) apply universally. Medical imaging uses ALARA to minimize necessary exposure.