Nuclear Medical Imaging Basics

Question 1

• Common tracer examples

Answer 1

MAA, MAG-3, FDG, FET, DOTATATE, PSMA

Question 2

Imaging/diagnosis: ?Bq
Therapy: ? Bq

Answer 2

Imaging/diagnosis: 10^6Bq
Therapy: ? 10^9Bq

Question 3

The radionuclide is either

Answer 3

gamma-ray-emitting or
positron-emitting

Question 4

Radioactive Decay

Answer 4

stochastic process in which an unstable nucleus transforms into a more stable
one by emitting particles, photons, or both, releasing energy in the process

Question 5

Important characteristics of each radionuclide:

Answer 5

• Mode of radioactive decay (Positron emission, alpha decay, β- decay, etc.)
• Type of emissions (positron, electron, gamma-ray, etc.)
• Transition energy
• Half life

Question 6

Particulate radiation

Electromagnetic radiation

Answer 6

Particulate radiation
* 𝛼 radiation:
 A lot of interaction processes
 Short range in tissue
 High tissue damage
* 𝜷− radiation:
 Many interaction processes
 Medium range in tissue
 High tissue damage

Electromagnetic radiation
* 𝜸 radiation or 𝛽+ annihilation
radiation:
 Few interaction processes
 Penetrating radiation
 Large range in tissue
 Detectable outside the patients’
body
 Photo peak at discrete energy

Question 7

Most commonly used PET radiotracer

Answer 7

Fluorodeoxyglucose (18F-FDG)
Glucose analog

Question 8

probability of interaction of the photons with matter depends on

Answer 8

*Energy Eγ of the gamma-ray photons
* Density ρ of the material
* Atomic number Z of the material
* Thickness Δx of the material