42. NUCLEAR MEDICINE: BETA MINUS DECAY

Question 1

1. What are the radionuclides that decay through Beta Minus Decay used for in Medicine?

Answer 1

• External Beam Radiotherapy
• Brachytherapy

Question 2

2. What happens during Beta Minus Decay?

Answer 2

• the parent nuclide decays into an excited daughter
  nuclide

Question 3

3. How does the daughter nuclide decay into its ground state?

Answer 3

• it does this instantaneously
• or it can do it through a metastable decay process

BY DOING SO:
- it emits the excitation energy
- this is in the form of Gamma Ray photons

Question 4

4. What are the Gamma ray photons used for?

Answer 4

• they are used for radiotherapy

Question 5

5. How many radio-nuclides are suitable for use in radiotherapy

Answer 5

• only a few
• this is out of the 3000 natural or artificial radionuclides

Question 6

6. Name the radionuclide that is mostly used for Radiotherapy?

Answer 6

• Cobalt 60
  it has a half life of 5.26 in an unstable state

Question 7

7. What does Cobalt 60 decay into?

Answer 7

• it decays into an excited Nickel 60 nuclide
• it decays instantaneously into its ground state
• this emits two gamma rays

Question 8

8. Does this image make sense?

Answer 8

• yes

NB:
- Q = the amount of energy released as Gamma Rays