AQA GCSE Physics (8463), Higher tier · Atomic structure › Hazards and uses of radiation
Practise Uses of nuclear radiation. 14 exam-style questions on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
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Give one way that nuclear radiation is used in medicine to control or destroy unwanted tissue.
Radiotherapy, e.g. aiming gamma rays at a tumour to kill the cancer cells.
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy4 marks
(a) Which two of the following are uses of nuclear radiation in medicine? Tick (✓) two boxes.[2]
Exploring internal organs using a radioactive tracer
Destroying cancer cells (radiotherapy)
Measuring body temperature
Measuring blood pressure
(b) A radioactive tracer is injected into a patient. The radiation is detected by a camera outside the body. Which type of radiation should the tracer emit? Tick (✓) one box.[1]
Alpha
Beta
Gamma
(c) Give one reason for your answer.[1]
Show the answer and mark scheme
(a)Answer: Exploring internal organs using a radioactive tracer; Destroying cancer cells (radiotherapy)
(b)Answer: Gamma
(c)Answer: Gamma rays pass out of the body to the camera and are only weakly ionising.
it can pass out of the body to reach the camera / it is the least ionising, so it causes the least damage to cells
Question 2Medium6 marks
Technetium-99m is used as a medical tracer. It is injected into a patient and collects in the organ being examined. A camera outside the body detects the radiation emitted. Technetium-99m emits gamma rays and has a half-life of 6 hours.
(a) Explain why an isotope that emits gamma rays is used as a tracer.[2]
(b) Explain why a half-life of 6 hours is suitable for a tracer.[2]
(c) Explain why an isotope that emits alpha particles would not be suitable as a tracer.[2]
Show the answer and mark scheme
(a)Answer: Gamma rays pass right out of the body to the camera, and they are only weakly ionising.
gamma rays are very penetrating, so they pass out of the body and reach the camera
gamma rays are weakly ionising, so they cause little damage to cells
(b)Answer: Long enough to complete the scan, but short enough that the activity soon becomes very low, keeping the dose small.
it is long enough for the tracer to reach the organ and for the images to be taken
it is short enough that the activity falls quickly after the scan, so the patient receives only a small dose
(c)Answer: Alpha particles would not get out of the body to the camera, and their strong ionisation would damage the tissue.
alpha particles would be absorbed in the body, so they could not be detected by the camera outside
alpha particles are strongly ionising, so they would damage the cells around the tracer
Question 3Hard8 marks
A patient has a tumour in the liver. Doctors are considering two treatments. Treatment A: tiny beads containing a beta-emitting isotope with a half-life of 64 hours are injected into the blood vessels that supply the tumour, where they become trapped. Treatment B: narrow beams of gamma rays from a source outside the body are aimed at the tumour from several directions, in a series of short sessions.
(a) Evaluate the two treatments.[6]
(b) Calculate the fraction of the initial activity of the beads that remains after 16 days.[2]
Show the answer and mark scheme
(a)Answer: A delivers short-range beta radiation right inside the tumour, sparing most healthy tissue, and decays away within weeks, but it puts radioactive material into the body. B is non-invasive and leaves nothing radioactive behind, but gamma rays also pass through healthy tissue, so the beams must be aimed from several directions.
A: the beads are in the tumour, so the radiation is delivered directly to the tumour cells
A: beta particles only travel a few millimetres in tissue, so they are absorbed by the tumour, with little damage to the rest of the body
A: beta particles are more ionising than gamma rays, so they are effective at destroying cells close to the beads
A: the 64-hour half-life delivers the dose over a few days, then the activity becomes very low (after 10 half-lives, about 27 days, it is about 1/1000)
A: the radioactive beads stay in the body and an invasive procedure is needed to inject them
B: no radioactive material is put into the body, so the patient is not contaminated
B: the gamma rays pass through healthy tissue on their way to and beyond the tumour, damaging healthy cells
B: aiming from several directions concentrates the dose on the tumour and spreads the dose to healthy tissue
B: several hospital visits are needed
a conclusion, e.g. A gives a large dose to the tumour with less damage to healthy tissue, but B avoids putting radioactive material inside the body
Marked with levels of response: the full level descriptors are in the app.