Radioactive Transitions

Question 1

what is radiation in the form of?

Answer 1

Energetic particles or photons

Question 2

In in-vivo nuclear medicine procedures what is the desirable range to use a radionuclide?

Answer 2

100-500 keV

Question 3

What is particle radiation?

Answer 3

Byproduct of the transition requiredfor desirable photon emissions

Question 4

What are the two types of changes that occur within a nucleus?

Answer 4

1. loss of energy

2. Change in atomic number in an isobaric transition

Question 5

Why does the transition always move downward?

Answer 5

The nucleus is decreasing energy by emitting radiation

Question 6

What are the steps of radioactive transition?

Answer 6

1. Isobaric transition
2. Isomeric transition
3. Interaction with orbiting electrons

Question 7

What are the 3 types of isobaric transition?

Answer 7

1. Beta emission
2. Positron emission
3. Electron capture

Question 8

What is crucial in nuclear stability?

Answer 8

neutron-proton ratio

Question 9

What happens if the neutron-proton ratio (N/P) is too low or too high?

Answer 9

The nucleus will eventually rearrange itself into a more stable configuration

Question 10

What is Beta radiation and what does it result in?

Answer 10

1. Emission of energetic electrons

2. N/P ratio is too high for stability

Question 11

What occurs when it is too low for stability?

Answer 11

1. Positron emission

2. Electron capture

Question 12

How is the condition relieved if the N/P is too high for stability?

Answer 12

Conversion of an internal neutron into a proton accompanied by the emission, from the nucleus, of an electron

Question 13

What are the two functions of electron or beta particle?

Answer 13

1. Carry away from the nucleus a one-unit negative charge so that a neutron can be converted into a proton with a one-unit positive charge,
2. carry off a portion of the energy given up by the nucleus

Question 14

What is the average beta energy?

Answer 14

usually between 25% and 30% of the maximum energy

Question 15

What is a positron?

Answer 15

A small particle that has essentially the same mass as an electron but has a positive rather than negative electrical charge

Question 16

What is the transition energy shared between?

Answer 16

Positron and a neutrino

Question 17

What happens when a positron particle is formed?

Answer 17

A proton is converted into a neutron

Question 18

What must the total transition energy be for positron emission to occur?

Answer 18

1.8 MeV

Question 19

How can a nucleus relieve neutron-proton ratio by?

Answer 19

Absorbing an electron from a shell

Question 20

What does electron capture create?

Answer 20

Vacancy in one shell

Quickly filled by an electron from a higher energy location

Question 21

When is Auger electrons produced?

Answer 21

When the energy given up by an electron filling the K-shell vacancy is transferred to another electron, knocking it out of its shell

Question 22

What do most Auger electrons have?

Answer 22

Relatively low energies

Question 23

What will nuclei in the intermediate state undergo?

Answer 23

isomeric transition by emitting energy and dropping to the ground state

Question 24

In most isomeric transition, what will nucleus emit its excess energy in the form of?

Answer 24

Gamma photon

Question 25

What is a gamma photon?

Answer 25

Small unit of energy that travels with the speed of light and has no mass

Question 26

What are the photon energies useful for diagnostic procedures?

Answer 26

Range of 100 keV to 500 keV

Question 27

What is the energy of a gamma photon determined by ?

Answer 27

Difference in energy between the intermediate and final states of nucleus undergoing isomeric transition

Question 28

What does alpha particle consist of?

Answer 28

Two neutrons and two protons

Question 29

How are beta emitters created?

Answer 29

neutron bombardment

Question 30

How can neutrons be obtained?

Answer 30

nuclear reactors or accelerators