Model

The simulation model accounts for :

• The numerical description of the tracer and attenuating media distributions.
• The modelling of the evolution of the activity concentration across time within each emitting region.
• The Poisson nature of positron emission, the positron range in tissues and the annihilation photons non-collinearity.
• Photoelectric, Compton and Rayleigh interactions in the tissues and in the scanner material.
• Accurate description of detection system (see figure).
• Fine tuning of the block sensitivity to encompass losses yielded by some detection effects that are not modelled in our program.
• Detector energy and spatial resolution modelling using gaussian blurring functions.
• Block, bucket and system dead-time and random contamination.

Computation efficiency

On average, 1 CPU hour (Opteron 246) is required per chunk of billion of disintegrations for standard brain studies (see the computation time in the database).
Whereas, PET-SORTEO is pretty fast compared to other simulators, it allows for parallel processing.

More informations about hte simulation model and its validation may be found in :

• A. Reilhac, C. Lartizien, N. Costes, S. Sans, C. Comtat, R. N. Gunn, and A. C.Evans, "PET-SORTEO: A Monte Carlo-based simulator with high count rate capabilities," IEEE Trans. Nucl. Sci., vol. 51, no. 1, pp. 46-52, Feb. 2004.
   
• A. Reilhac, G. Batan, C. Michel, C. Grova, J. Tohka, N. costes, and A. C.Evans, "PET-SORTEO: Validation and Development od database of simulated PET volumes," accepted in IEEE Trans. Nucl. Sci., 2005.