Radioactivity

Question 1

Define Radioactivity

Answer 1

Spontaneous emission of radiation, either directly from unstable atomic nuclei or because of a nuclear reaction

Question 2

What is the annual millisievert exposure?

Answer 2

20 millisieverts

Question 3

How can you use radionuclides in diagnostic nuclear medicine

Answer 3

Function and anatomy
Nervous system
Circulatory system
Skeletal system
Urinary system

Question 4

What happens when there are too many neutrons in the nucleus?

Answer 4

Radioactive decay

Question 5

What happens when there is too many protons in the nucleus?

Answer 5

Positron emission

Question 6

What is an Isobar?

Answer 6

different Z, same A

Question 7

What is an Isotope?

Answer 7

same Z, different A

Question 8

What is an Isomer?

Answer 8

same Z and A

Question 9

What does Isomeric mean?

Answer 9

From metastable (radioactive) to ground state (stable)

Question 10

How can a nucleus be unstable?

Answer 10

Too many protons or neutrons
Or incorrect arrangement

Question 11

What does a becquerel represent?

Answer 11

SI unit
1 nuclear disintegration per second
Rate of decay
(Bq)

Question 12

Repulsive forces

Answer 12

Exist between protons

Question 13

Attractive forces

Answer 13

Exist between neutrons over short ranges

Question 14

What are the two types of Beta particle decay

Answer 14

Negatron B- emission
Positron B+ emission

Question 15

Explain Negatron B- emission

Answer 15

When a nucleus has too many neutrons, the N:P ratio is too high
A B- particle results from the transformation of a neutron in the nucleus to a proton
The B- particle may carry a part of the energy released, and shares part of the energy with an antineutrino which is ejected at the same time.
The number of neutrons decreases, the number of protons increases (decreasing neutron: proton ratio)

Question 16

Explain Positron B+ emission

Answer 16

The emission of a positive Beta particle is associated with the breakdown of nuclides which have too many protons, the N:P ratio is too low
Proton turns into neutron within nucleus
A proton is emitted with a positron (positron emission)
As a result, the number of neutrons in the nucleus is increased by 1 and the number of protons is reduced by 1

Question 17

Electron capture

Answer 17

When a nuclide has too many protons, the nucleus captures one of the K shell electrons and combines it with a proton to form a neutron
This results in orbital vacancy which produces a cascade effect in the electron shells to fill the vacancy
This releases energy in the form of characteristic radiation

Question 18

Physical vs biological half-life

Answer 18

Physical- the time taken for the element to decay by half
Biological- influences that change the radioactive dose to the patient (hydration, location)

Question 19

Why is a shorter half-life beneficial?

Answer 19

Cheaper
Patients/staff receive less radiation
Residual activity is low

Question 20

What to do when a radioactive spill occurs

Answer 20

Inform
Confine/contain
Decontaminate