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The table gives some information about four radioactive isotopes - OCR Gateway - GCSE Physics - Question 5 - 2019 - Paper 1
Question 5
The table gives some information about four radioactive isotopes. Which isotope is the best to use as a medical tracer? | Half life | Radiation emitted | |----... show full transcript
Worked Solution & Example Answer:The table gives some information about four radioactive isotopes - OCR Gateway - GCSE Physics - Question 5 - 2019 - Paper 1
Step 1
Which isotope is the best to use as a medical tracer?
Answer
When selecting a radioactive isotope for use as a medical tracer, several factors must be considered including the type of radiation emitted and the half-life of the isotope.
Type of Radiation: Gamma radiation is generally preferred for medical tracers because it can penetrate tissues and is detectable outside the body without causing significant harm. Alpha radiation, on the other hand, is less suitable because it cannot penetrate the skin and can be harmful if ingested or injected.
Half-Life: The half-life of a tracer should be appropriate for the diagnostic procedure. A tracer that decays too quickly may not provide sufficient imaging time, while a tracer that decays too slowly could result in prolonged exposure to radiation.
Evaluating the Options:
- Isotope A: 6 hours, alpha radiation (not suitable)
- Isotope B: 6 hours, gamma radiation (suitable)
- Isotope C: 6 minutes, gamma radiation (suitable but very short half-life)
- Isotope D: 6 years, beta radiation (not suitable)
After evaluating these factors, Isotope B, which has a half-life of 6 hours and emits gamma radiation, is the most suitable choice for use as a medical tracer.