Evaluate using nuclear radiation in medicine (6 marks)

"The benefits of using radioactive sources in medicine outweigh the risks." Evaluate this statement, referring to at least one diagnostic and one therapeutic use.

Mark scheme (6 marks — levelled):

Level 3 (5–6 marks): Detailed, balanced evaluation with specific examples and a justified conclusion. Likely to include:

• Diagnostic: technetium-99m as a medical tracer — gamma emitter, short half-life (~6 hours) so dose falls quickly, low ionising power so minimal cell damage, allows imaging of organs (e.g. thyroid, bones).
• Therapeutic: cobalt-60 / external gamma radiotherapy or internal beta sources (iodine-131 for thyroid cancer) — high-energy radiation kills cancer cells.
• Risks: ionising radiation can damage DNA and cause mutations / cancer; risk to medical staff (need shielding, dosimeters, ALARA principle); contamination risk with internal sources.
• Conclusion: for life-threatening illness, benefits clearly outweigh small statistical risk if dose is controlled; less justified for trivial conditions.

Level 2 (3–4 marks): Some examples and some risks, partial conclusion.

Level 1 (1–2 marks): Limited examples, mostly one-sided, no clear conclusion.

0 marks: No relevant content.