Exam-style question
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For Defects of vision and correction, which option best uses PET annihilation photons to answer this objective: Calculate lens power where appropriate.?.
- A.Use PET annihilation photons: detecting opposite gamma photons from positron decay, so the answer is anchored to coincidence detection.
- B.Use a clinical description only, without naming the measured physical signal.
- C.Assume all tissue produces the same detector response, so no useful contrast is formed.
- D.Ignore the limitation or safety factor and treat the method as risk-free.
Model answer
What a good answer should say
- The correct option is Use PET annihilation photons: detecting opposite gamma photons from positron decay, so the answer is anchored to coincidence detection.
Explanation
Why this works
It is correct because PET annihilation photons gives a specific physical mechanism and connects the detector or image evidence to the objective. The other options are incorrect because they either avoid the measured signal, remove contrast or detection detail, or ignore a limitation that AQA medical physics answers should consider.
Common mistake
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