# Calculating fractional uptake rate (FUR) image

FUR image can be calculated from dynamic (multi-frame) or static (single-frame) PET image. However, plasma time-activity curve (TAC) must be measured continuously from injection time to the FUR calculation time, because the FUR method needs the AUC of the input function.

## Steps to compute a FUR image:

1. If you have a late-scan PET image then make sure that the image frame times and physical decay have been corrected to the injection time instead of scan start time (which is the default)
2. Make sure that radioactivity concentrations in the plasma data file and in the PET image are in the same calibration units or that both data at least contain the correct information on the calibration units
3. Depending on the tracer, plasma TAC may have to be metabolite corrected
4. Calculate the FUR image using Carimas or imgfur
5. FUR image can then be processed further as any parametric image.

## Steps to compute a MR or GU image:

Metabolic rate (MR) or glucose uptake (GU) image can be calculated as above using imgfur, except that the following information must be given to the program on the command line:

• Concentration of native substrate (for example glucose) in plasma with option -Ca
• Lumped constant with option -LC
• Tissue density (ρ) with option -density

If necessary, read more detailed information in the user help text for imgfur.