The overall goal of this renewal application is to improve the effectiveness of single photon emission tomography (SPECT) imaging for the diagnosis and treatment of patients with cancer. More specifically, it focuses on the capabilities of modern SPECT systems that include X-ray computed tomography systems (CT) with a focus on the estimation of activity concentration. This proposed effort will include a systematic phantom exploration of two SPECT/CT systems (one with cone beam CT and one with 16 slice helical CT) with 16 different combinations of isotopes and collimators. The data will be collected in the current sinogram binned mode and, in parallel, in listmode (keeping all events above 50 keV). A 4 cm diameter 57Co cylinder with calibrated 57Co standards for the dose calibrator will be used to determine a conversion factor from counts/pixel to activity/volume. These data will be used to explore the feasibility of such a calibration measurement (one isotope, one collimator) and scaling factors to apply that calibration to all isotope/collimator combinations. As part of ths effort we will develop more accurate scatter and collimator response modeling using accelerated Monte Carlo simulation in the image reconstruction process. This new effort is an outgrowth of our previous work, under this grant funding, in exploring quantitation in PET, including isolating many sources of error, finding ways to minimize them, and exploring alternative scanner geometries. That work also included image reconstruction with modeling scanner non-stationary resolution response. As part of our previously funded research, a Simulation System for Emission Tomography (SimSET) has been developed. This Monte Carlo-based software package tracks photons through complex heterogeneous objects (patients) and models the effects of collimation and detection. The package has been essential to our efforts and has been adopted by more than 300 other investigators in their own work. Part of our effort will be to continue to improve SimSET with significance acceleration of SPECT collimator simulation tools. The SimSET software package is freely available via the Internet.
Single Photon emission tomography (SPECT) has now been combined with X-ray Computed tomography (CT) to provide a single scanner that can image both physiology and anatomy. This grant will develop techniques to make quantitative SPECT/CT more available as a practical and cost effective clinical tool to make more specific diagnosis of disease and monitoring response to therapy than current techniques allow. This work is another step toward personalized medicine where therapies are tailored to the individual patient.
|MacDonald, L R; Harrison, R L; Alessio, A M et al. (2011) Effective count rates for PET scanners with reduced and extended axial field of view. Phys Med Biol 56:3629-43|
|Harrison, Robert L (2010) Introduction To Monte Carlo Simulation. AIP Conf Proc 1204:17-21|
|Harrison, Robert L (2010) Monte Carlo Simulation Of Emission Tomography And Other Medical Imaging Techniques. AIP Conf Proc 1204:126-132|
|Hunter, William C J; Harrison, Robert L; Gillispie, Steven B et al. (2009) Parametric Design Study of a Long Axial Field-of-View PET Scanner using a Block-Detector Tomograph Simulation of a Cylindrical Phantom. IEEE Nucl Sci Symp Conf Rec (1997) 2009:3900-3903|
|Alessio, Adam M; Schmitz, Ruth E; Macdonald, Lawrence R et al. (2008) Image Reconstruction for a Partially Collimated Whole Body PET Scanner. IEEE Trans Nucl Sci 55:975-983|
|Macdonald, L R; Schmitz, R E; Alessio, A M et al. (2008) Measured count-rate performance of the Discovery STE PET/CT scanner in 2D, 3D and partial collimation acquisition modes. Phys Med Biol 53:3723-38|
|Harrison, Robert L; Kinahan, Paul E; Lewellen, Thomas K (2007) A generalized simulation description language. IEEE Nucl Sci Symp Conf Rec (1997) 5:4012-4014|
|Schmitz, Ruth E; Harrison, Robert L; Stearns, Charles W et al. (2007) Optimization of noise equivalent count rate performance for a partially collimated PET scanner by varying the number of septa. IEEE Trans Med Imaging 26:935-44|
|Alessio, Adam M; Kinahan, Paul E; Lewellen, Thomas K (2006) Modeling and incorporation of system response functions in 3-D whole body PET. IEEE Trans Med Imaging 25:828-37|
|Alessio, Adam M; Kinahan, Paul E (2006) Improved quantitation for PET/CT image reconstruction with system modeling and anatomical priors. Med Phys 33:4095-103|
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