Imaging In Inflammation And Infections

Question 1

What is molecular imaging?

Answer 1

Term that covers imaging using molecules such as radionuclide imaging and PET

Question 2

What is radionuclide used to image?

Answer 2

Bones, organs and other parts of the body

Question 3

What are the steps to radionuclide imaging? (4)

Answer 3

1. Intravenous injection of dose of radiopharmaceutical
2. Makes the patient radioactive so they release photons
3. The perpendicular photons detected by lead collimator
4. Gamma camera takes in photons and converts them to an image

Question 4

What are radiopharmaceuticals?

Answer 4

Radioisotopes which decay leading to emission of gamma rays

Question 5

What are gamma rays?

Answer 5

Part of high frequency, high energy, low wavelength region of the electromagnetic spectrum

Question 6

What are the components of radiopharmaceuticals?

Answer 6

Radioactive element - isotope which decays overtime

Pharmaceutical element - determines where the drug goes in the body

Question 7

What is technetium ?

Answer 7

A clinically used radiopharmaceutical. Binds to molecules allowing it to produce images of certain systems.

Question 8

Properties of a good isotope (6)

Answer 8

1. Short half-life similar to examination length
2. gamma emitter rather than beta and alpha
3. energy of gamma rays should be between 50-300
4. radiopharmaceutical should be really available
5. easily bind to the pharmaceutical element
6. radiopharmaceutical is easy to prepare

Question 9

How does a gamma camera work?

Answer 9

1. Radioisotope decays
2. Gamma rays released
3. Perpendicular rays taken in by collimator
4. Gamma rays hits crystals on gamma camera that produces light
5. Light displays image

Question 10

Radiation dose (4)

Answer 10

1. Higher dose = better quality image
2. Limit to dose given as radiation is harmful to the body
3. Metal objects destruct image
4. Dose of radiation must have more benefits than risks

Question 11

What does SPECT stand for?

Answer 11

Single photon emission computed tomography

Question 12

How does a SPECT work?

Answer 12

Similar to CT

• radio pharmaceutical injected into the body to make it radio active
• emit gamma ray
• gamma camera rotates around body and picks up gamma rays after it has gone through collimator

USED FOR CARDIAC AND BRAIN STUDIES

Question 13

What does PET stand for?

Answer 13

Positron emission tomography

Question 14

What is PET

Answer 14

Uses radionuclides that decay by positron emission - cause annihilation reaction

Used to detect any abnormal tissues to see any FDG build up - useful to see how far cancer has spread

Question 15

What are the steps involved in PET?

Answer 15

Involves intravenously injecting radiotracer - most commmon type FDG which can be traced in body

Seeing build up of FDG in body shows areas of infection

Question 16

What is FDG taken up in the body by? (6)

Answer 16

• brain
• myocardium
• stomach
• liver
• spleen
• urinary tract

Question 17

What are the benefits of imaging?

Answer 17

Help in diagnosis

Treatment option

Question 18

What are the risks of imaging?

Answer 18

Radiation is bad - leads to cancer

Costly