Academic Appointments

Honors & Awards

  • Breast Cancer Research Program (BCRP), Department of Defense (DOD) (May 2010- April 2013)
  • Henri Benedictus Fund, Belgian American Educational Foundation (BAEF) and the King Baudouin Foundation (July 2008- June 2009)

Research & Scholarship

Current Research and Scholarly Interests

I am interested in Positron Emission Tomography (PET) physics, instrumentation, and its application in cancer diagnosis and patient management. My work focusses on PET front-end detectors, data acquisition, and system simulation. The goal is to improve spatial and energy resolution yielding a better image quality. Currently I am working on constructing, commissioning, and characterizing a high precision, 1 mm^3 resolution breast specific PET camera.


Journal Articles

  • Analog signal multiplexing for PSAPD-based PET detectors: simulation and experimental validation PHYSICS IN MEDICINE AND BIOLOGY Lau, F. W., Vandenbroucke, A., Reynolds, P. D., Olcott, P. D., Horowitz, M. A., Levin, C. S. 2010; 55 (23): 7149-7174


    A 1 mm(3) resolution clinical positron emission tomography (PET) system employing 4608 position-sensitive avalanche photodiodes (PSAPDs) is under development. This paper describes a detector multiplexing technique that simplifies the readout electronics and reduces the density of the circuit board design. The multiplexing scheme was validated using a simulation framework that models the PSAPDs and front-end multiplexing circuits to predict the signal-to-noise ratio and flood histogram performance. Two independent experimental setups measured the energy resolution, time resolution, crystal identification ability and count rate both with and without multiplexing. With multiplexing, there was no significant degradation in energy resolution, time resolution and count rate. There was a relative 6.9 ± 1.0% and 9.4 ± 1.0% degradation in the figure of merit that characterizes the crystal identification ability observed in the measured and simulated ceramic-mounted PSAPD module flood histograms, respectively.

    View details for DOI 10.1088/0031-9155/55/23/001

    View details for Web of Science ID 000284261000015

    View details for PubMedID 21081831

  • Physical effects of mechanical design parameters on photon sensitivity and spatial resolution performance of a breast-dedicated PET system MEDICAL PHYSICS Spanoudaki, V. C., Lau, F. W., Vandenbroucke, A., Levin, C. S. 2010; 37 (11): 5838-5849


    This study aims to address design considerations of a high resolution, high sensitivity positron emission tomography scanner dedicated to breast imaging.The methodology uses a detailed Monte Carlo model of the system structures to obtain a quantitative evaluation of several performance parameters. Special focus was given to the effect of dense mechanical structures designed to provide mechanical robustness and thermal regulation to the minuscule and temperature sensitive detectors.For the energies of interest around the photopeak (450-700 keV energy window), the simulation results predict a 6.5% reduction in the single photon detection efficiency and a 12.5% reduction in the coincidence photon detection efficiency in the case that the mechanical structures are interspersed between the detectors. However for lower energies, a substantial increase in the number of detected events (approximately 14% and 7% for singles at a 100-200 keV energy window and coincidences at a lower energy threshold of 100 keV, respectively) was observed with the presence of these structures due to backscatter. The number of photon events that involve multiple interactions in various crystal elements is also affected by the presence of the structures. For photon events involving multiple interactions among various crystal elements, the coincidence photon sensitivity is reduced by as much as 20% for a point source at the center of the field of view. There is no observable effect on the intrinsic and the reconstructed spatial resolution and spatial resolution uniformity.Mechanical structures can have a considerable effect on system sensitivity, especially for systems processing multi-interaction photon events. This effect, however, does not impact the spatial resolution. Various mechanical structure designs are currently under evaluation in order to achieve optimum trade-off between temperature stability, accurate detector positioning, and minimum influence on system performance.

    View details for DOI 10.1118/1.3484059

    View details for Web of Science ID 000283747600030

    View details for PubMedID 21158296

  • Performance characterization of a new high resolution PET scintillation detector PHYSICS IN MEDICINE AND BIOLOGY Vandenbroucke, A., Foudray, A. M., Olcott, P. D., Levin, C. S. 2010; 55 (19): 5895-5911


    Performance of a new high resolution PET detection concept is presented. In this new concept, annihilation radiation enters the scintillator detectors edge-on. Each detector module comprises two 8 × 8 LYSO scintillator arrays of 0.91 × 0.91 × 1 mm(3) crystals coupled to two position-sensitive avalanche photodiodes (PSAPDs) mounted on a flex circuit. Appropriate crystal segmentation allows the recording of all three spatial coordinates of the interaction(s) simultaneously with submillimeter resolution. We report an average energy resolution of 14.6 ± 1.7% for 511 keV photons at FWHM. Coincident time resolution was determined to be 2.98 ± 0.13 ns FWHM on average. The coincidence point spread function (PSF) has an average FWHM of 0.837 ± 0.049 mm (using a 500 ?m spherical source) and is uniform across the arrays. Both PSF and coincident time resolution degrade when Compton interactions are included in the data. Different blurring factors were evaluated theoretically, resulting in a calculated PSF of 0.793 mm, in good agreement with the measured value.

    View details for DOI 10.1088/0031-9155/55/19/018

    View details for Web of Science ID 000282061800018

    View details for PubMedID 20844332

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