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A Double-Edged Sword
☢️ A Double-Edged Sword
The same radiation that can cause cancer can also cure it. The same gamma rays used to sterilise surgical equipment are the ones that kill tumour cells in radiotherapy. Radioactivity is one of science's greatest paradoxes: the very property that makes it dangerous — the ability to damage biological molecules — is exactly what makes it medically useful. The key is always about control: the right type, the right amount, directed at the right place, for the right time.
Medical Uses of Radiation
Radioactive isotopes are invaluable in medicine for both diagnosis (finding what's wrong) and treatment (fixing it).
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🧠 Memory Aids
Matching radiation to use: Think about what properties each use needs:
- Smoke detectors — need to stay INSIDE the detector → short-range → Alpha
- Paper thickness — need to partially go through paper → Medium penetration → Beta
- Checking welds — need to go through thick metal → Maximum penetration → Gamma
- Medical tracers — need to escape the body to be detected → Gamma
Safety 3Ds: Distance, Duration (minimise time), Dense shielding (lead). Always apply the 3Ds when working with radiation.
Irradiation vs Contamination: "Irradiation = Illuminated from outside (like a lamp). Contamination = Contaminated from inside (like a dye in water)."
Now try it yourself
Quiz · Question 1 of 17
Which type of radiation is used in smoke detectors?
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This topic in real past papers
Every real exam question we've found on uses & hazards of radiation, with a full worked answer.