High doses of ionizing radiation can cause which of the following health effects?

• A. Hair loss, blood changes, illness, and death
• B. Improved immune function
• C. No effects at any dose
• D. Only skin burns

Answer: (B)

High doses of ionizing radiation cause serious health effects by damaging rapidly dividing cells in the body, especially those in the bone marrow, hair follicles, and the lining of the gut. This leads to hair loss, changes in blood cell counts (white cells, red cells, and platelets), resulting in illness and a higher risk of infection or bleeding, and can be fatal at very high exposures. Immune function is not improved by high-dose radiation; in fact, immune responses are typically suppressed due to damage to immune cells. The idea of no effects at any dose is incorrect because high doses clearly produce acute health effects, and saying “only skin burns” ignores the widespread, systemic damage that can occur beyond the skin.