SUV- standardised uptake values in pet scanning

Hunter Health Imaging Service

Todd Charge Senior Technologist Nuclear Medicine and PET Centre Hunter Health Imaging Service

SUV’s - A Brief Overview of Silly Useless Values.


Standardised Uptake Values

Quantification has always held a pervasive allure for Nuclear Medicine.

There is a sense that anything that can be quantified should be.

J.W. Keyes Jr. PET Centre North Carolina USA Journal Nuclear Medicine 1995; 36:1836-1839


What are SUV’s?

A measure of FDG uptake as a function of time

Quantitative evaluation of tumour metabolism

Often used as a measure of malignancy vs. benignancy of lesion


Standardised Uptake Value

Data courtesy Mount Vernon Hospital


Standardised Uptake Value Pre Treatment

SUV = 18

Post Treatment

SUV = 4



eightdose/bodywSUV )/(TC

=

Where C/(T) = FDG concentration in tissue at time T



Tracer concentration is usually determined from the image pixel that shows the highest lesion activity

Average concentration was once used but is not routinely in use now


Assumptions of SUV’s

Negligible free FDG in tissue at time of PET scan

Equilibrium reached between plasma and free FDG in tissue

All tissues are affected in the same way by glucose levels


Variables Influencing SUV’s Large number of variables which need to be

taken into account. Patient size Measurement times Plasma Glucose ROI Partial Volume Effect Camera specifications


Summary Use of Lean Body Mass instead of true

weight Take plasma glucose levels into account,

tumour type & possible treatment effects Standardise uptake time, attenuation

correction, scatter correction and filtering Consider ROI placement and use of max

pixel


Summary

Only use SUV within institution and even camera specific

Be careful when using SUV threshold to distinguish tumour from normal tissue

Consider SUV in conjunction with a subjective analysis of a lesion.


Summary Overall, recognise SUV’s for what they are:

A helpful clue, but not the final answer.


References

DiChiro G, Brooks RA. “PET quantitation: Blessing and Curse.” J Nucl Med 1988:29;1603-1604

S Meikle “Quantitative Methods and Factors Affecting SUV Calculation” ANZSNM PET Workshop 2003

JW Keyes “SUV: Standard Uptake or Silly Useless Value?” J Nucl Med 36:1836-1839, 1995

SUV- standardised uptake values in pet scanning

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