Sabet Lab

About the lab

PI: Hamid Sabet

Research activities in Sabet Lab fall into the category of radiation physics and instrumentation that span over many areas of medical and non-medical applications. These projects mainly fit into development of high-performance and advanced radiation detectors by rigorously studying and addressing fundamental limitations of current radiation detector systems. Current research include fabrication of high-performance scintillation detectors using laser-induced optical barriers (LIOB) technique, light transport simulation in crystals, detector-, and system-level modeling of radiation detectors, and system integration and characterization. Developing high-performance cardiac SPECT system, novel brain and small animal PET systems, photon counting CT detector system, and multimodality intraoperative imaging system are the current active projects.

Research

Laser Processed Scintillators

Laser processed scintillators.
Photos of LYSO:Ce, CsI:Tl, and NaI:Tl scintillators for PET and SPECT as well as light guide processed with the LIOB technique
Photos of LYSO:Ce, CsI:Tl, and NaI:Tl scintillators for PET and SPECT as well as light guide processed with the LIOB technique

Light transport simulations for detector performance evaluation

Performance comparison of laser processed LIOB:Ce with mechanically pixelated/monolithic scintillators. [Publication]

Light transport simulations for detector performance evaluation. Performance comparison of laser processed LIOB:Ce with mechanically pixelated/monolithic scintillators

Comparison of the characteristics of the four detector categories. The Mechanical array and the all-way barrier patterns were simulated with a 1 mm thick light guide (RI=1.5). A, C, and D show the results for polished crystal/pixels for the mechanical array and the monolithic crystal, and barrier RI=1.0 and interface roughness characterized by σα=20° for the laser-processed detectors. A: LRF for four adjacent MPPC pixels under a beam scan through the center of the detector. B: FWHM of the LRF, for a central MPPC pixel, as a function of DOI and the characteristics of the optical barriers in the case of laser-processed detectors, and surface roughness of the crystal/pixels in the case of the mechanical array and the monolithic crystal. The error bars correspond to the 95% confidence interval of the fitting parameter. C: Flood maps showing the sum of 7 (8 in the case of half- way barriers) discrete interaction depths. D: Line profiles through a central and an edge row in the above flood maps. For the monolithic detector and the half way barriers the depth dependence of the flood map is large making the line profiles not illustrative.


Dynamic Cardiac SPECT

A stationary SPECT system for dynamic cardiac imaging applications

GATE mode of DC-SPECT, a stationary dynamic cardiac SPECT system, with 80 detector modules each viewing the entire field of view. This geometry is facilitated by using detectors with high intrinsic resolution. This geometry yields ~15x more sensitivity at the same resolution compared with conventional dual head gamma cameras.
GATE mode of DC-SPECT, a stationary dynamic cardiac SPECT system, with 80 detector modules each viewing the entire field of view. This geometry is facilitated by using detectors with high intrinsic resolution. This geometry yields ~15x more sensitivity at the same resolution compared with conventional dual head gamma cameras.

Scintillator-based photon counting CT detector

Scintillator-based photon counting CT detector

Scintillator-based photon counting CT detector

In scintillator-based photon counting CT detector, scintillator pixels and photodetector pixels are coupled one to one. This is necessary to achieve high light collection efficiency, high light confinement, and hence high SNR. The bottle neck is to fabricate scintillator pixels with small cross-section. Shown in the figure is 1.5 mm thick LYSO:Ce crystal processed with the LIOB technique with various pixel size.


Members

Fellows

    Students

      Research Assistants

        Selected Publications

        • Blackberg L, Sajedi S, El Fakhri G, Sabet H. A layered single-side readout DOI TOF-PET detector. Phys Med Biol 2020 ():
        • Sajedi S, Sabet H, Choi HS. Intraoperative biophotonic imaging systems for image-guided interventions. Nanophotonics 2019 8 (1):99-116
        • Bläckberg L, Moebius M, Fakhri GE, Mazur E, Sabet H. Light Spread Manipulation in Scintillators Using Laser Induced Optical Barriers. IEEE Trans Nucl Sci 2018 65 (8):2208-2215
        • Bläckberg L, Sajedi S, Mandl S, Mohan A, Vittum B, El Fakhri G, Sabet H. Exploring light confinement in laser-processed LYSO:Ce for photon counting CT application. Phys Med Biol 2019 64 (9):095020
        • P Sheikhzadeh, H Sabet, H Ghadiri, P Geramifar, P Ghafarian, and MR Ay. 7/9/2018. “Concept design and Monte Carlo performance evaluation of HeadphonePET: a novel brain-dedicated PET system based on partial cylindrical detectors.” Journal of Instrumentation, 13, 07, Pp. P07008
          View in: Journal of Instrumentation
        • Salar Sajedi, Navid Zeraatkar, Mohsen Taheri, Sanaz Kaviani, Hadi Khanmohammadi, Saeed Sarkar, Hamid Sabet, and Mohammad Reza Ay. 3/14/2018. “Generic high resolution PET detector block using 12× 12 SiPM array.” Biomedical Physics & Engineering Express, 4, 3, Pp. 035014.
          View in: Biomedical Physics & Engineering Express
        • Bläckberg L, El Fakhri G, Sabet H. Simulation study of light transport in laser-processed LYSO:Ce detectors with single-side readout. Phys Med Biol 2017 62 (21):8419-8440
        • Sheikhzadeh P, Sabet H, Ghadiri H, Geramifar P, Mahani H, Ghafarian P, Ay MR. Development and validation of an accurate GATE model for NeuroPET scanner. Phys Med 2017 40 ():59-65
        • Uzun D Ozsahin, Lisa Bläckberg, G El Fakhri, and H Sabet. 1/30/2017. “GATE simulation of a new design of pinhole SPECT system for small animal brain imaging.” Journal of Instrumentation, 12, 01, Pp. C01085
          View in: Journal of Instrumentation
        • Kaviani S, Zeraatkar N, Sajedi S, Akbarzadeh A, Gorjizadeh N, Farahani MH, Teimourian B, Ghafarian P, Sabet H, Ay MR. Design and development of a dedicated portable gamma camera system for intra-operative imaging. Phys Med 2016 32 (7):889-97
        • Sabet H, Bläckberg L, Uzun-Ozsahin D, El-Fakhri G. Novel laser-processed CsI:Tl detector for SPECT. Med Phys 2016 43 (5):2630
        • Lisa Bläckberg, Michael Moebius, Narjes Moghadam, Dilber Uzun-Ozsahin, Eric Mazur, Georges El Fakhri, and Hamid Sabet. 10/29/2016. “Scintillator-based Photon Counting Detector: is it feasible?” Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD), 10/29/2016. IEEE
          View in: IEEE library

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