Calculating parametric BPND and DVR image

Basis function method

Steps to compute parametric map of binding potential (BPND) or distribution volume ratio (DVR) using simplified reference tissue model (SRTM):

  1. Copy the dynamic PET image file from PETPACS to your local disk
  2. Find the SIF file for this image; if SIF file does not exist, then create it
  3. Draw ROI on the reference region, and calculate and save its time-activity curve (TAC) in a TAC file (do not include any other regional TACs in the file)
  4. Check the θ3 constraints for this study protocol (see below)
  5. Execute program imgbfbp in command prompt window. Remember to enter the θ3 constraints using options -min and -max, and preferably also threshold limit 10% using option -thr=10

Include also option -DVR, if DVR image is needed instead of BPND image.

Determination of constraints for θ3

Suggested constraints in Turku PET Centre

Table 1. Suggested θ3 constraints for calculation of BF-SRTM in Turku. Please note that units are [min-1], not [s-1] as in publication by Gunn et al., 1997.
PET tracer Parametric images Regional TACs
min max min max
[C-11]FLB 0.03(1 0.60(1 - -
[F-18]SPA-RQ 0.03 0.6 0.01 0.6
[C-11]PIB 0.05 0.6 0.04 0.6
[C-11]raclopride 0.06 0.6 0.06 0.6

(1 Fixed limits in RPM software, used and discussed by Cselényi et al., 2006.

Constraints for θ3 may need to be re-evaluated when imaging parameters that affect the noise properties of the PET image are substantially changed (scanner, reconstruction, framing, study length, injected dose, ...).

If your PET tracer is not in the table

Ask Jouni Tuisku to determine the constraints for the tracer. For this purpose, you must provide a couple of dynamic images (control subject and patient, basal state and intervention etc), TAC of reference region, and preferably ROI files of all regions that may be of interest in regional or SPM analysis.

Issues to consider when determining the constraints for θ3

Multilinear method

Program imgsrtm transforms the SRTM into multilinear form, and uses non-negative least squares method (NNLS) to estimate the model parameters. It can be used to compute BPND, DVR, R1, k2, and k2' images. With option -SRTM2 it uses the modification of simplified reference tissue model SRTM2 or MRTM2, where the original SRTM method is used first to calculate median k2' (k2 of reference region) from all pixels where BPND, and thereafter SRTM is run another time with fixed k2'.

See also:


Cselényi Z, Olsson H, Halldin C, Gulyás B, Farde L. A comparison of recent parametric neuroreceptor mapping approaches based on measurements with the high affinity PET radioligands [11C]FLB 457 and [11C]WAY 100635. Neuroimage 2006; 32: 1690-1708. doi: 10.1016/j.neuroimage.2006.02.053.

Gunn RN, Lammertsma AA, Hume SP, Cunningham VJ. Parametric imaging of ligand-receptor binding in PET using a simplified reference region model. Neuroimage 1997; 6: 279-287. doi: 10.1006/nimg.1997.0303.

Lammertsma AA, Hume SP. Simplified reference tissue model for PET receptor studies. Neuroimage 1996; 4: 153-158. doi: 10.1006/nimg.1996.0066.

Liukko K. Using basis function method for parametric mapping. TPCMOD0027.

Rizzo G, Turkheimer FE, Bertoldo A. Multi-scale hierarchical approach for parametric mapping: assessment on multi-compartmental models. NeuroImage 2013; 67: 344-353. doi: 10.1016/j.neuroimage.2012.11.045.

Sederholm K. Study on basis function methods reliance on θ3 parameter limits - study with simulated [11C]raclopride images. TPCMOD0028.

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Updated at: 2020-01-01
Created at: 2006-05-23
Written by: Vesa Oikonen, Kaisa Liukko, Jouni Tuisku