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Table 1 Commonly used radiotracers in evaluation of neurodegenerative syndromes

From: Multimodality imaging of neurodegenerative disorders with a focus on multiparametric magnetic resonance and molecular imaging

 

FDG-PET

Amyloid PET

Tau PET

Patient Preparation

4 to 6 h fasting

Abstain from heavy exercise for 24 h prior to injection

Following injection sit quietly in dimly lit room with eyes open

No special preparation

No special preparation

Administered activity MBq (mCi)

185–740 (5–20)

F-18-Florbetapir 370 (10)

F-18-Florbetaben 300 (8)

F-18-Flutemetamol 185 (5)

F-18-Flortaucipir 370 (10)

Effective dose

0.019 mSv/MBq

~ 6–7 mSv

~ 8–9 mSv

Uptake period (minutes)

30–60

F-18-Florbetapir 30–50

F-18-Florbetaben 45–130

F-18-Flutemetamol 90

*Note dynamic imaging immediately following bolus can also be performed to estimate cerebral blood flow

F-18-Flortaucipir 80

Acquisition time (minutes)

 

F-18-Florbetapir 10

F-18-Florbetaben 15–20

F-18-Flutemetamol 20

F-18-Flortaucipir 20

Normal study

Uptake within the cerebral cortex and deep gray nuclei greater than cerebellum

Uptake within the cerebral white matter

Absence of neocortical uptake. Note there can be significant off-target binding in the striatum, choroid plexus, and brainstem nuclei which is considered normal

Abnormal study

Regions within the cerebral cortex and deep gray nuclei with decreased metabolic activity compared to cerebellum (with the exception of Parkinson plus syndromes which lead to cerebellar hypometabolism)

Uptake in the cerebral white matter with blurring of the corticomedullary junction, with various named signs (tree in summer, kissing hemispheres, etc.)

Increased contiguous neocortical activity, generally involving greater than one area

  1. PET Positron emission tomography, MBq Megabecquerel, mCi Millicurie, mSv Millisievert