Simulation System for Emission Tomography (SimSET): using simulation to research ideas in

emission tomography.

Robert L. Harrison, Steven B. Gillispie, Thomas K. Lewellen

University of Washington

Supported in part by PHS grant CA42593

SimSET

• Freely available.

• Photon-tracking simulation.

• PET and SPECT.

• Well engineered.

• Command-line driven.

Using simulation as a research tool

• Problem definition.

• Choosing and installing a simulation.

• Setting up and running a simulation.

• Analyzing the data.

Problem definition

Possible areas of research

• Optimizing patient studies.

• Assessing/improving quantitation.

• Designing tomographs.

Diffuse lung disease

• Reproducing work by Chicco et al.*

• Can disease be detected in SPECT scans of the lungs?

• Cold lesions in hot lung.• Vary size of lesions.• 30% of lung volume affected.

* Chicco, Eur J Nucl Med, 28:150-154.

Choosing and installing a simulation

Choosing SimSET

a

Analyticsimulations(e.g., ASIM)General purposephoton-trackingtomograph simulations(e.g., SimSET,PETSIM, SIMIND)High energy physicssimulations(e.g., GATE, EGS,MCNP, Penelope)Greater flexibility, accuracyGreater speed, ease-of-use

Installing SimSET

• Download from website.

• Unpack (e.g., gunzip).

• Customize links to your system.

• Make run file.

Setting up and running a simulation

General setup

• Scan time, number of decays, …

• Location of parameter files, data tables, etc.

• Object (phantom/patient) geometry.

• Tomograph geometry.

• Output specification.

Defining the object

• Define the activity and attenuation objects.

• We are using the NCAT phantom.*

* Segars and Tsui, IEEE Trans Nucl Sci, 49:3:675-679, 2002.

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Defining the tomograph

• Collimator parameter file.– LEGP.

• Detector parameter file.– Planar detector.

Defining the output

• 62 slices.

• Distance-angle sinograms (128 angles over 360°, 128 3mm distance bins).

• 10% energy window.

Analyzing the data

Analyzing the data

• Filtered backprojection reconstruction.

• Observer study.

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No lesions 8mm3 lesions 16mm3 lesions

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SimSET Summary

• Freely available emission tomography simulation.

• Efficient, easy-to-use.

• Useful for a broad range of research.

For further information

• Website:– http://depts.washington.edu/simset/html/simset_main.html

• Contact:– simset@u.washington.edu