Examples of GATE simulation Yun Dong

Different systems available in GATE Scanner: most generic system; Cylindrical PET: cylindrical geometry; CPET: simulate C-PET Plus, Philips Medical Systems; SPECT Head: model SPECT dedicated scanners; ECAT: simulate ECAT of CPS Innovations;

System geometry: 3 Rings,  820mm; each ring has 48 blocks; each block has 8  8 crystals with 0.3 mm gap; each crystal is 6.45  6.45  25mm LSO; Thus, there are totally 24 slices. Phantom: cylinder,  200mm, 190mm length; water Example One

Digitizer: Energy Resolution: Energy Window: 350~650keV Timing Resolution: 2ns Coincidence Window: 12ns Source: 1,000,000 Becquerel; back-to-back 511keV gamma ray; uniform distribution in phantom;

Single events eventID | rsID | cryID | T(s) | E(KeV) | srcX(mm) | srcY | srcZ | glbX | glbY | glbZ | Scatter e e e e … before blurringafter blurring

Coincidence Events eventID | rsID | cryID | T(s) | E(KeV) | srcX(mm) | srcY | srcZ | glbX | glbY | glbZ | TSR e e T e e S e e R... What we can do with coincidence events? Estimation of performance of system: sensitivity; scatter fraction (SF), S/(T+S); NECR curve: T*T/(T+S+R) Reconstruction: conventional reconstruction via position; reconstruction w/ TOF; reconstruction w/ depth of interaction; Lots of other things

Example Two Our question: Good energy resolution and bad timing resolution vs. Bad energy resolution and good timing resolution Because of many kinds of simulation need to run, we choose in GATE simulation: Turn off the energy resolution Turn off the energy window Turn off the timing resolution Turn off the coincidences window

No blurring single events eventID | rsID | cryID | T(s) | E(KeV) | srcX(mm) | srcY | srcZ | glbX | glbY | glbZ | Scatter e e e e … After we get enough no blurring single events, we use C code to add energy resolution, energy window, timing resolution to the each no blurring single event. Then by the choice of coincidences window, we acquire the coincidence events by ourselves. It is similar with GATE but we can adjust easily the ER,EW,TR and CW followed what we need. That saves time.

To evaluate the trade-off between ER and TR, analysis of NECR curve is our first step doing with TOF PET GATE simulation. The next step we are doing now is to reconstruct images and evaluate the image quality. Until that, we could answer our question.

GATE Simulation of PET Conclusion Estimation of scanner performance New system design Imaging Reconstruction

Thanks