Chapter 29 - PET and SPECT

Question 1

Single-photo emission computed tomography principle

Answer 1

Collect gamma camera images from different angles to obtain better spatial resolution and higher contrast and improved sensitivity

Question 2

Positron emission tomography principle

Answer 2

Radionuclides emit positrons to become stable

PET better than SPECT at picking up photos and better spacial resolution 3-4 mm

Question 3

Common tracers in vascular surgery for nuclear imaging

Answer 3

1) 18F Fluorodeoxyglucose FDG –> cannot be metabolized and trapped in cytosol
2) 18F sodium fluoride - skeletal imaging with rapid bone uptake and blood clearance
3) labelled WBC

Question 4

FDG on plaque

Answer 4

suggest transient plaque inflammation indicating possible future complications

Question 5

Atherosclerosis process over time and different imaging modalities

Answer 5

Early = FDG only
Later stage with active calcification = FDG + NaF
Density of calcium reach threshold = CT as well
Calcification exceed inflammation = no more FDG
Dense without anymore calcium turnover = no more NaF

Question 6

FDG and immunosuppressive therapy

Answer 6

unreliable in patients who have received immunosuppressive therapy to demonstrate inflammation