Development of a Practical Calibration Procedure for a Clinical SPECT/MRI System Using a Single INSERT Prototype Detector and Multimini Slit-Slat Collimator

In the context of the INSERT project, we have been developing a clinical single photon emission computed tomography (SPECT) insert for a magnetic resonance imaging (MRI) system, in order to perform simultaneous SPECT/MRI of the human brain. This system will consist of 20 CsI:Tl scintillation detectors, 5-cm wide and 10-cm long, with a 72-channel silicon photomultiplier (SiPM) readout per detector, and a multimini slit-slat (MSS) collimator set up in a stationary partial ring. Additionally the system has a custom-built transmit/receive MR coil to ensure compatibility with the SPECT system. Due to the novel design of the system/collimator, existing geometric calibration methods are not suitable. Therefore we propose a novel and practical calibration procedure that consists of a set of specific independent measurements to determine the geometric parameters of the collimator. This procedure was developed utilizing a prototype system that consists of a reduced-size single detector with a 36-channel SiPM-based readout and a single MSS collimator module. Validation was performed by reconstructing different imaging phantoms, using a rotating stage to simulate a tomographic acquisition. Regarding uniformity, the coefficient of variation (COV) for the cylinder phantom reconstructed with correct calibration parameters is 6.7%, whereas the COV using incorrect parameters is 9.4%. The quality of the phantom reconstructions provide evidence of the applicability of the proposed method to the calibration of the prototype system. This procedure can be easily adapted for the final INSERT system.

[1]  B. Hutton,et al.  Variance prediction in SPECT reconstruction based on the Fisher information using a novel angular blurring algorithm for computation of the system matrix , 2013, 2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC).

[2]  Tianyu Ma,et al.  Initial studies of PET-SPECT dual-tracer imaging , 2007, 2007 IEEE Nuclear Science Symposium Conference Record.

[3]  B. Hutton,et al.  Effects of the collimator magnification factor in the geometrical calibration of SPECT systems , 2016, 2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD).

[4]  H H Barrett,et al.  A stationary hemispherical SPECT imager for three-dimensional brain imaging. , 1993, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[5]  P. Suetens,et al.  Characterization of Acquisition Geometry of Pinhole SPECT , 2022 .

[6]  Shielding requirements of a SPECT insert for installation in a PET/MRI system , 2015, 2015 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC).

[7]  Kathleen Vunckx,et al.  Small animal imaging with multi-pinhole SPECT. , 2009, Methods.

[8]  M. Occhipinti,et al.  Mapping tool for investigation of component-level PCB compatibility in multimodal MRI/SPECT , 2016, 2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD).

[9]  L. R. Furenlid,et al.  A System Calibration and Fast Iterative Reconstruction Method for Next-Generation SPECT Imagers , 2012, IEEE Transactions on Nuclear Science.

[10]  Freek J. Beekman,et al.  The role of preclinical SPECT in oncological and neurological research in combination with either CT or MRI , 2014, European Journal of Nuclear Medicine and Molecular Imaging.

[11]  Johan Nuyts,et al.  Perturbative Refinement of the Geometric Calibration in Pinhole SPECT , 2008, IEEE Transactions on Medical Imaging.

[12]  R. D. de Rosales,et al.  Potential clinical applications of bimodal PET-MRI or SPECT-MRI agents† , 2014, Journal of labelled compounds & radiopharmaceuticals.

[13]  David T. Jones,et al.  Statistical SPECT processing in MRI-negative epilepsy surgery , 2014, Neurology.

[14]  Brian F. Hutton,et al.  Collimator Design for a Brain SPECT/MRI Insert , 2015, IEEE Transactions on Nuclear Science.

[15]  Carlo Fiorini,et al.  Development of a SiPM-based Anger camera for INSERT, a new multi-modality SPECT/MRI system for preclinical and clinical imaging , 2014, 2014 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC).

[16]  Roger Lecomte,et al.  Geometrical calibration for an animal PET converted SPECT , 2010, IEEE Nuclear Science Symposuim & Medical Imaging Conference.

[18]  Tianyu Ma,et al.  Determination of geometrical parameters for slit-slat SPECT imaging on MicroPET , 2007, 2007 IEEE Nuclear Science Symposium Conference Record.

[19]  Donald W. Wilson,et al.  FastSPECT II: a second-generation high-resolution dynamic SPECT imager , 2002, IEEE Transactions on Nuclear Science.

[20]  Alexandre Bousse,et al.  Evaluation of a partial ring design for the INSERT SPECT/MRI system , 2015, EJNMMI Physics.

[21]  E. Hoffman,et al.  3-D phantom to simulate cerebral blood flow and metabolic images for PET , 1990 .

[22]  Donald W. Wilson,et al.  Calibration of Scintillation Cameras and Pinhole SPECT Imaging Systems , 2005 .

[23]  C. Piemonte,et al.  Experimental Evaluation of a SiPM-Based Scintillation Detector for MR-Compatible SPECT Systems , 2015, IEEE Transactions on Nuclear Science.

[24]  C. Fiorini,et al.  Light response estimation and gamma events reconstruction in gamma-detectors based on continuous scintillators and SiPMs , 2016, 2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD).

[25]  B. Hutton,et al.  Novel collimation for simultaneous SPECT/MRI , 2014, 2014 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC).

[26]  Frans van der Have,et al.  System Calibration and Statistical Image Reconstruction for Ultra-High Resolution Stationary Pinhole SPECT , 2008, IEEE Transactions on Medical Imaging.

[27]  Patrick Dupont,et al.  Characterization of pinhole SPECT acquisition geometry , 2003, IEEE Transactions on Medical Imaging.

[28]  I. Perali,et al.  A compact SiPM photodetector array for SPECT applications , 2014, 2014 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC).