# Calculation of SUV image

Parametric SUV map can be calculated from dynamic (multi-frame) or static (single-frame) PET image.

It is strongly recommended to use software provided by scanner manufacturer (such as ADW) to analyze PET-CT follow-up studies, when SUV is the only parameter of interest!

SUV image can be processed further like any parametric image.

## SUV image from dynamic PET image

SUV or %i.d./L image can be calculated from predetermined time range in a dynamic image.

Use program imgsuv in command prompt window. For example, if injected dose is 200 MBq and subject weight is 70 kg, and SUV mean from 40 to 60 min p.i. is to be calculated, enter the following command:

imgsuv myimage.v 40 60 200 70 mysuvimage.v


Resulting image data will be in units g/mL, although unit will not be saved in the output image files.

If you prefer to calculate percentage of injected dose per Litre tissue, enter 0 instead of patient weight.

Program imgsuv relies on the stored calibration units in the original PET image. In case of errors or unrealistic results, check and correct the image units, for example with program imgunit.

## SUV image from static PET image

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).

Proceed as with dynamic image, except enter zeroes for the calculation start and end times. For example:

imgsuv mystaticimage.v 0 0 200 70 mystaticsuvimage.v


## Convert dynamic PET image into SUV units

If you do not wish to calculate SUV mean in a certain time range but want just to convert radioactivity concentrations into SUV units (g/mL), you can also use program imgsuv, but enter zeroes in place of start and end times, for example:

imgsuv myimage.v 0 0 200 70 mydynamicsuvimage.v


## Alternative steps to compute SUV image

### 1. Prepare the single-frame image

The PET image must contain only one (late) frame. If necessary, the frame number and times can be viewed with eframe.

If PET image contains more than one frame, the selected frames can be summed together using

• imginteg with option -avg
• ecatsum; do not use option -i

Alternatively, to separate one (late) frame from a dynamic study, use esplit.

### 2. Check the units

Make sure that the kilos in body weight and radioactivity units in the image are cancelled out in the SUV calculation. If necessary, convert the units in image or injected dose.

For example, if injected dose is in MBq, PET image in Bq/cc, and animal weight in g, PET image must be divided by (Dose/Mass)×106. If PET image is in kBq/cc and body weight in kg, then PET image can be divided simply by (Dose/Mass).

### 3. Calculation

For the SUV computation, program imgcalc can be used to divide the image by injected dose normalized to body weight, lean body weight, or body surface area (BSA). The command could be e.g.

imgcalc ua789static.v / 0.253 ua789suv.v


All the mentioned commands can be given in command prompt window.

### 4. Regional SUV (if needed)

Regional quantitative SUV values can then be calculated from the SUV images as usual. SUV images can also be compared directly with SPM, or visually in presentations or scientific publications.

Regional SUV can be also be calculated from regional time-activity curves with dftsuv.

## References:

Miyashita K, Takahashi N, Oka T, Asakawa S, Lee J, Shizukuishi K, Inoue T. SUV correction for injection errors in FDG-PET examination. Ann Nucl Med. 2007; 21(10): 607-613. doi: 10.1007/s12149-007-0068-1.

Shin H-B, Sheen H, Lee H-Y, Kang J, Yoon D-K, Suh TS. Digital imaging and communications in medicine (DICOM) information conversion procedure for SUV calculation of PET scanners with different DICOM header information. Phys Med. 2017; 44: 243-248. doi: 10.1016/j.ejmp.2017.05.063.

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Updated at: 2017-10-22
Created at: 2007-11-01
Written by: Vesa Oikonen