RADIATION: Uses, Risks & Safety

Quick Take

Radiation is all around us. It powers medicine, industry, and energy but too much can harm humans, animals, and the environment. Safety rules and careful monitoring are key.

 What is Radiation?
Energy traveling as waves or particles.
- Non-ionizing: radio, microwaves, visible light.

- Ionizing: X-rays, gamma rays, high-energy particles → can damage DNA.

Dose units: Gray (Gy) = energy absorbed, Sievert (Sv) = biological effect.

Background exposure: 2–3 mSv/year (natural sources).

Positive Uses
Medical Imaging
Chest X-ray: ~0.1 mSv
CT scan: 5–10 mSv
Helps diagnose fractures, infections, cancer → improves survival.

 Radiotherapy
Treats cancer by killing tumor cells (40–70 Gy).
Proven for breast, prostate, head & neck cancers.
Some healthy tissue may receive dose.

 Industrial & Sterilization
Sterilizes syringes, tools, some food (10–30 kGy).
Non-destructive testing for welds & structures.

 Energy Production
Nuclear power produces electricity with low greenhouse emissions.
Accidents like Chernobyl/Fukushima are rare but serious.

 Negative Effects
 Acute Radiation Syndrome (ARS)
High dose, short time → nausea, vomiting, hair loss, bone marrow failure.
Lethal > ~4 Gy.

 Deterministic vs Stochastic Effects
Deterministic: above threshold → severity rises with dose (burns, cataracts).
Stochastic: cancer risk rises with dose; no threshold.

 Cancer & Genetic Risks
Excess solid cancer: ~0.5 per Sv (atomic bomb studies).
Pregnancy: high doses → developmental harm.
Heritable genetic effects in humans: limited evidence, inconclusive.

 Environmental Impacts
Wildlife: mutations, population changes (e.g., Chernobyl).
Long-term ecosystem effects: still under study.

 Safety & Regulation
ALARA: As Low As Reasonably Achievable.
Public exposure: ≤1 mSv/year (artificial sources).
Occupational: 20 mSv/year avg. over 5 years.
Medical: justify & optimize each procedure.
Industrial: shield, limit time, increase distance.

Radiation is useful but risky.
Benefits: medicine, sterilization, electricity.
Risks: ARS, cancer, developmental harm.
Safety measures save lives.
Low-dose effects & long-term ecology remain uncertain.