4.4.3.3 Uses of Nuclear Radiation

Question 1

Uses of nuclear radiations in medicine:

Answer 1

• exploration of internal organs
• control or destruction of unwanted tissue

Question 2

Explanation of use of radiation as a tracer:

Answer 2

• It is injected/swallowed and there is enough time for it flow through the
  body and be detected before it decays away but is only present for a short
  enough time to minimise any harm from radiation
• It is a gamma emitter, so can pass through the body tissue without being
  absorbed (as it is the most penetrating)

Question 3

Explanation of use of radiation as a smoke alarm:

Answer 3

• alpha emitter, and used in smoke alarms
• It is emitted into the air around the alarm, and does not reach far because alpha is weakly penetrating
• If smoke reaches the alarm, the amount of alpha particles in the surrounding air drops as smoke particles stop/absorb alpha radiation
• decrease in count rate of alpha radiation is detected causing the alarm to sound
• long half life means it’s count rate is approximately constant - doesn’t need to be rep,axed very often
• weak activity means it won’t be harmful to anyone
• cannot use beta or gamma as they would penetrate smoke particles (higher penetration) so no decrease in count rate would be detected

Question 4

Explanation of use of radiation as chemotherapy:

Answer 4

• Gamma emitters are used to emit gamma rays, ,which are directed onto certain areas of the body with cancerous cells, which absorb the energy and die, controlling the disease
• gamma radiation has high penetrating power so can pass through tissues acting as a tracer and then pass out of the body and is less likely to be absorbed reducing damage done to body
• It is used to control any other unwanted tissue too
• However, as it is hard to direct accurately, surrounding healthy cells may also be
  irradiated, and their destruction causes unhealthy side effects
• short half-life - less damage to cells/tissues/organs/body
• low ionising power - less damage to cells/tissues/organs/Boyd
• high penetration means it can be detected outside the body
• emits gamma radiation