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Updated: May 28, 2026
A Basic Positron Emission Tomography System Constructed to Locate a Radioactive Source in a Bi-dimensional Space
Published on: February 1, 2016
Fast Monte Carlo-simulator with full collimator and detector response modelling for SPECT
Antti O Sohlberg1, Markus T Kajaste
1Department of Clinical Physiology and Nuclear Medicine, Joint Authority for Päijät-Häme Social and Health Care, Lahti, Finland. antti.sohlberg@phsotey.fi
Objective:
Monte Carlo (MC)-simulations have proved to be a valuable tool in studying SPECT-reconstruction algorithms. Despite their popularity, the use of Monte Carlo-simulations is still often limited by their large computation demand. This is especially true in situations where full collimator and detector modelling with septal penetration, scatter and X-ray fluorescence needs to be included. This paper presents a rapid and simple MC-simulator, which can effectively reduce the computation times.
Methods:
The simulator was built on the convolution-based forced detection principle, which can markedly lower the number of simulated photons. Full collimator and detector response look-up tables are pre-simulated and then later used in the actual MC-simulations to model the system response. The developed simulator was validated by comparing it against (123)I point source measurements made with a clinical gamma camera system and against (99m)Tc software phantom simulations made with the SIMIND MC-package.
Results:
The results showed good agreement between the new simulator, measurements and the SIMIND-package. The new simulator provided near noise-free projection data in approximately 1.5 min per projection with (99m)Tc, which was less than one-tenth of SIMIND's time.
Conclusion:
The developed MC-simulator can markedly decrease the simulation time without sacrificing image quality.
