Critique PET/CT

PET/CT critique

What is the half life of F-18?

110min

Fill in the blanks: Many malignant tumors have ____ affinity for ____ than normal cells

high; glucose

T/F: FDG is not trapped within the cell and can re-cross the cell membrane

false

T/F: FDG is trapped within the cell, and cannot cross the cell membrane

true

What is the emission type, and energy of F-18?

2 photons @ 180 degrees apart

511keV

In PET imaging, we are imaging the positrons or photons of a tracer?

photons

What is true-coincidence?

Simultanious detection of 2 emissions resulting from single decay event

What is scatter coincidence?

when one or both photons from single event are scattered and both are detected

What is random coincidence?

simultaneous detection of emission from more than 1 decay event

This is an example of _____ coicidence

True

This is an example of _____ coincidence

Random

This is an example of _____ coincidence

Random

T/F: A pet scanner in 3D acquisition mode has led septa in between detector blocks

False

T/F: A pet scanner in 2D acquisition mode has led septa in between detector blocks

true

What is the main difference in detector configuration between a 2D and 3D PET scanner?

2D is collimated, 3D is not

What patient information should be acquired prior to an FDG PET scan?

height/weight

NPO 4-6 hrs?

Have diabetes?/Measure glucose

allergies, if administering CT contrast

patient history

What is a normal adult FDG PET dose? What is the typical dose at most institutions?

5-20mCi

10-12mCi

What is the pediatric dose range for an FDG PET scan?

0.1-0.14mCi/kg

When is imaging performed post FDG injection?

60-90min

What should you have the patient do immediately before a PET scan?

Void

When imaging patients with cancer in the pelvis, what can be done to improve image quality?

catheterize patient, administer Diuretics to promote excretion

What are the most common and constant sites of intesne uptake of FDG?

brain

liver (moderate)

kidneys (calyces and pelvis)

bladder

What are normal variable areas of activity on an FDG PET scan?

Salivary Glands

Thyroid

Heart and Vessels

Spleen

Stomach

Bowel

Bone Marrow

Muscles

Testicles

What can cause muscle uptake on a FDG PET scan?

exercise or weight lifting day before PET scan

This FDG PET scan demonstrates:

Muscle uptake due to exercise