Development and Validation of a Monte Carlo Simulation Tool for Multi-Pinhole SPECT

PurposeIn this work, we developed and validated a Monte Carlo simulation (MCS) tool for investigation and evaluation of multi-pinhole (MPH) SPECT imaging.ProceduresThis tool was based on a combination of the SimSET and MCNP codes. Photon attenuation and scatter in the object, as well as penetration and scatter through the collimator detector, are modeled in this tool. It allows accurate and efficient simulation of MPH SPECT with focused pinhole apertures and user-specified photon energy, aperture material, and imaging geometry. The MCS method was validated by comparing the point response function (PRF), detection efficiency (DE), and image profiles obtained from point sources and phantom experiments. A prototype single-pinhole collimator and focused four- and five-pinhole collimators fitted on a small animal imager were used for the experimental validations. We have also compared computational speed among various simulation tools for MPH SPECT, including SimSET-MCNP, MCNP, SimSET-GATE, and GATE for simulating projections of a hot sphere phantom.ResultsWe found good agreement between the MCS and experimental results for PRF, DE, and image profiles, indicating the validity of the simulation method. The relative computational speeds for SimSET-MCNP, MCNP, SimSET-GATE, and GATE are 1: 2.73: 3.54: 7.34, respectively, for 120-view simulations. We also demonstrated the application of this MCS tool in small animal imaging by generating a set of low-noise MPH projection data of a 3D digital mouse whole body phantom.ConclusionsThe new method is useful for studying MPH collimator designs, data acquisition protocols, image reconstructions, and compensation techniques. It also has great potential to be applied for modeling the collimator-detector response with penetration and scatter effects for MPH in the quantitative reconstruction method.

[1]  B.M.W. Tsui,et al.  A mathematical observer study for the evaluation and optimization of compensation methods for myocardial SPECT using a phantom population that realistically models patient variability , 2004, IEEE Transactions on Nuclear Science.

[2]  M. S. Kaplan,et al.  Coherent scatter implementation for SimSET , 1997 .

[3]  Eric C. Frey,et al.  Combination of MCNP and SimSET for Monte Carlo simulation of SPECT with medium and high energy photons , 2001, 2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310).

[4]  Benjamin M W Tsui,et al.  Integration of SimSET photon history generator in GATE for efficient Monte Carlo simulations of pinhole SPECT. , 2008, Medical physics.

[5]  Rik Van de Walle,et al.  Monte Carlo simulation in PET and SPECT instrumentation using GATE , 2004 .

[6]  Michael A. King,et al.  An optimization of reconstruction parameters and investigation into the impact of photon scatter in /sup 67/Ga SPECT , 2002 .

[7]  R. A. Forster,et al.  MCNP - a general Monte Carlo code for neutron and photon transport , 1985 .

[8]  C E Metz,et al.  The geometric transfer function component for scintillation camera collimators with straight parallel holes. , 1980, Physics in medicine and biology.

[9]  Y. Yonekura,et al.  Ultra-high resolution SPECT system using four pinhole collimators for small animal studies. , 1995, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[10]  S. Meikle,et al.  Small animal SPECT and its place in the matrix of molecular imaging technologies , 2005, Physics in medicine and biology.

[11]  H. Atkins,et al.  Pinhole SPECT: an approach to in vivo high resolution SPECT imaging in small laboratory animals. , 1994, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[12]  V. Kohli,et al.  Investigation of OPET performance using GATE, a Geant4-based simulation software , 2003, 2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515).

[13]  Eric C Frey,et al.  Development of a 4-D digital mouse phantom for molecular imaging research. , 2004, Molecular imaging and biology : MIB : the official publication of the Academy of Molecular Imaging.

[14]  Yong Choi,et al.  Optimization of pinhole collimator for small animal SPECT using Monte Carlo simulation , 2002 .

[15]  Horst Halling,et al.  Compact high resolution detector for small animal SPECT , 1999, 1999 IEEE Nuclear Science Symposium. Conference Record. 1999 Nuclear Science Symposium and Medical Imaging Conference (Cat. No.99CH37019).

[16]  I Buvat,et al.  Monte Carlo simulations in SPET and PET. , 2002, The quarterly journal of nuclear medicine : official publication of the Italian Association of Nuclear Medicine (AIMN) [and] the International Association of Radiopharmacology.

[17]  B. Hasegawa,et al.  A multipinhole small animal SPECT system with submillimeter spatial resolution. , 2006, Medical physics.

[18]  P. V. van Rijk,et al.  U-SPECT-I: a novel system for submillimeter-resolution tomography with radiolabeled molecules in mice. , 2005, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[19]  D L Kirch,et al.  Thallium-201 myocardial perfusion scintigraphy: results of standard and multi-pinhole tomographic techniques. , 1979, The American journal of cardiology.

[20]  Ronald J. Jaszczak,et al.  Analytic determination of the pinhole collimator's point-spread function and RMS resolution with penetration , 2001, 2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310).

[21]  G. Santin,et al.  GATE: a Geant4-based simulation platform for PET and SPECT integrating movement and time management , 2003 .

[22]  Eric C Frey,et al.  Optimum compensation method and filter cutoff frequency in myocardial SPECT: a human observer study. , 2002, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[23]  E C Frey,et al.  Scatter compensation methods in 3D iterative SPECT reconstruction: a simulation study. , 1997, Physics in medicine and biology.

[24]  Craig S. Levin.  TU‐D‐J‐6B‐01: Small Animal PET and SPECT: Instrumentation, Performance, and Applications , 2005 .

[25]  C E Metz,et al.  Theoretical prediction of the geometric transfer function for focused collimators. , 1974, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[26]  R. Jaszczak,et al.  Pinhole collimation for ultra-high-resolution, small-field-of-view SPECT. , 1994, Physics in medicine and biology.

[27]  E C Frey,et al.  Improved estimation of the detector response function for converging beam collimators. , 1998, Physics in medicine and biology.

[28]  G T Gullberg,et al.  The geometric transfer function for cone and fan beam collimators. , 1990, Physics in medicine and biology.

[29]  D L Kirch,et al.  Seven-pinhole tomography--a technical description. , 1981, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[30]  Benjamin M. W. Tsui,et al.  Pinhole SPECT With Different Data Acquisition Geometries: Usefulness of Unified Projection Operators in Homogeneous Coordinates , 2007, IEEE Transactions on Medical Imaging.