Emerging Technologies 2018 Session Listing
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Session C4: Radiation Detection and Imaging
Start Time: 09:00, Friday, May 11
Chaired by Jan Iwanczyk, DxRay, Inc. (email@example.com)
- 9:00 Paul Lecoq, CERN-European Organization for Nuclear Research
A metamaterial approach to reach 10 ps timing resolution with a scintillator-based detector
The future generation of radiation detectors is more and more demanding on timing performance for a wide range of applications, such as time of flight (TOF) techniques for PET cameras, precise event time tagging in high luminosity accelerators and a number of photonic applications based on single photon detection.
There is a consensus for gathering Europe’s multidisciplinary academic and industrial excellence around the ambitious challenge to develop a 10ps TOF PET scanner (TOFPET). The goal is to reduce the radiation dose, scan time, and costs per patient, all by an order of magnitude.
To achieve this ambitious goal it is essential to improve the performance of each component of the detection chain: light production, light transport, photodetection, readout electronics.
This talk will concentrate on the light production and light transport. It will be shown that the introduction of a number of disruptive technologies, such as multifunctional heterostructures combining the high stopping power of well know scintillators with the ultrafast photon emission resulting from the 1D, 2D or 3D quantum confinement of the excitons in nanocrystals, as well as photonic crystals and photonic fibers, open the way to new radiation detector concepts with unprecedented performance.
- 9:20 Maurice Garcia-Sciveres, Lawrence Berkeley National Laboratory
Challenges of high rate and radiation "imaging" in particle physics
Reconstructing patterns of radiation emerging from subatomic particle collisions is related to conventional imaging, but presents unique challenges. While similar to pixellated imagers, the detectors used must sample the position and timing of subatomic particles shooting through them instead of capturing intensity maps. By precisely positioning a large number of detector elements, the samples collected allow high fidelity reconstruction of the trajectories of many particles simultaneously, thus producing 3-dimensional "images" of sprays of particles from energetic collisions. Science goals push towards larger detector assemblies and at the same time higher rate of collisions, leading to a number of unique challenges not found in imaging applications. These include operating for years without access in a radiation environment of hundreds of krad/hr, tens of MHz frame rate with sparse readout, custom power distribution and readout solutions to achieve very low mass and radiation resistance, and micron level mechanical stability of large assemblies cooled to low temperature. This presentation will introduce the challenges and focus on the present state of the art readout integrated circuit solutions for particle detectors.
- 9:40 Yi-Hwa Liu, Yale University
Near-field coded aperture imaging: potential for high-sensitivity and high-resolution SPECT
Imaging distributed sources with near-field coded aperture (CA) collimation remains extremely challenging and is customarily considered next to impossible for single-photon emission computerized tomography (SPECT) due to the intricate multiplexing (overlapping) counts acquired via CA. We proposed novel CA planar and SPECT reconstruction approaches and evaluated feasibilities of imaging and reconstructing distributed hot sources and cold lesions using near-field CA and iterative image reconstruction. A series of 2-D digital and 3-D physical phantoms were used for method valuations. Ex vivo rat heart with myocardial infarction was imaged using a micro- SPECT system equipped with a custom-made CA module and a commercial 5-pinhole collimator. Rat CA images were reconstructed via the 3-D maximum likelihood expectation maximization algorithm, and 5-pinhole images were reconstructed using the commercial software provided by the micro-SPECT system. Results from the 2-D digital phantom, 3-D physical phantom and small-animal study demonstrated that our proposed 2-D and 3-D CA SPECT imaging and reconstruction approaches worked reasonably well, indicating the potential of high- sensitivity and high-resolution near-field CA SPECT. Future work remains to be done would be (1) improvement of coded aperture mask designs, (2) incorporation with solid state gamma detectors, and (3) development of new demultiplexing algorithms for CA image reconstructions.
- 10:00 William Barber, Rapiscan Technologies
Edge illuminated direct conversion semiconductor X-ray imaging detectors
Direct conversion semiconductor x-ray imaging based on edge illuminated pixelated arrays can provide better energy resolution compared to scintillation detectors, while also providing higher dynamic range and output count rate (OCR) compared to front or back side illuminated semiconductor detectors. Direct conversion provides a more efficient energy transfer as compared to scintillators and edge illumination provides for rapid charge collection independent of the depth of interaction in semiconductors. We have developed room temperature x-ray imaging detectors for medical and security imaging applications using this approach. The imaging detectors are made using direct conversion Silicon (Si) or Cadmium Telluride (CdTe) integrated with mixed signal application specific integrated circuits (ASICs). The use of energy information in medical and security x-ray imaging applications, obtained using energy integrating detectors and switching energy levels on the x-ray tube, is leading lower dose for comparable image quality and/or increased contrast for a specific imaging task. Fast energy dispersive detectors of this type could outperform these methods by providing the energy information in a single scan with a single energy level on the x-ray tube. We demonstrate the tiling of modules to achieve the required OCR, lp/mm, and kVp for 2D and 3D x-ray imaging.
- 10:20 COFFEE BREAK
(Mt. Curie Foyer)
- 10:40 Chin-Tu Chen, University of Chicago
with C. Kao, L. Leoni, H. Zhang, S. Cheng, M. Bhuiyan, N. Chen, N. Eclov, H. Kim, J. George, B. Quigley, H. Tsai, A.
Kucharski, J. Souris, C. Pelizzari, R. Freifelder, I. Balyasnikova, L. Meng, P. La Riviere and L. Lo
Imaging-guided X-ray induced photodynamic therapy (XPDT) using novel nanoparticles
We have been developing a Molecular RadioNano-Theranostics Research Program, emphasizing on integrating nuclear medicine technology with nanotechnology to deliver precision medicine using novel molecular diagnostic imaging and image-guided molecular therapy approaches. We have successfully developed following key emerging technologies with a central theme on X-ray induced photodynamic therapy (XPDT): (1) multi-modality molecular imaging instrumentation in PET, SPECT, CT and optical imaging using novel semiconductor-based radiation detector technologies; (2) molecular radionano-theranostic chemistry integrating radioimmuno-technology and nanotechnology with target delivery considerations; (3) image reconstruction, processing and analysis using accurate physical modeling, novel algorithm designs, and fast computing techniques. We will illustrate our progresses by demonstrating the uses of x-ray nanoscintillators capable of generating significant amount of cytotoxic reactive oxygen species (ROS) under low-dose, low-energy x-ray activation in XPDT treatment of ovarian cancer. Our nanoplatform Y2O3:Eu@mSiO2 is used not only to generate singlet oxygen but to also deliver radiosensitizing and other therapeutic drugs. In animal experiments using ovarian cancer models, we are using several innovative imaging devices, designed and developed in our own laboratories, to monitor the luminescence and fluorescence signals for treatment planning and assessment, as well as for evaluation of the tumor progression and therapeutic effects after the XPDT treatment using SPECT and PET radiotracer imaging methods.
- 11:00 Jan Dudak, Czech Technical University in Prague
with J. Karch and J. Zemlicka
Sub-micron resolution X-ray imaging using large-area photon counting detector Timepix
X-ray micro-CT is nowadays a widely accessible imaging tool as a number of compact and high-quality X-ray imaging systems have become available on the market. The state-of-the-art micro-CT systems are capable to routinely perform scans with spatial resolution at level of several micrometers. Nevertheless, data acquisition with sub-micron precision remains a sophisticated task. Challenges come mostly from prolongation of the acquisition time inevitably connected with use of nano-focus sources providing low photon flux compared to widely used micro-focus X-ray tubes. That usually results in decreased signal-to-noise ratio of projection images. Furthermore, even effects like thermal expansion of the setup components or source spot drift become important and can induce severe artifacts to the reconstructed CT data.
The use of photon counting detector (PCD) technology can efficiently overcome the SNR issue. Prolongation of acquisition time does not compromise the image quality since PCDs operation is dark-current-free.
This contribution evaluates performance of a custom-built laboratory micro-CT system equipped with a nano-focus X-ray tube and a large- area PCD Timepix for CT scans with effective pixel size bellow one micrometer. Both SNR and mechanical stability during scans are addressed and quality of CT reconstructions is demonstrated.
- 11:20 Magdalena Bazalova-Carter, University of Victoria
X-ray fluorescence CT imaging: a new way of viewing gold
- 11:40 Vesna Sossi, University of British Columbia
Advances in PET/MR multimodality imaging: relevance to the study of brain function
Recent understanding of brain function stresses the importance of the interaction between brain connectivity and underlying neurochemistry and metabolism, both in terms of energy cost of brain function as well as in terms of understanding of pathogenic processes. Indeed, the network degeneration hypothesis states that initiation and progression of disease-specific pathological changes occur within specific brain structural and functional networks (best investigated with MRI) and are mediated by abnormal protein aggregation, inflammation and impaired cellular energetics coupled to abnormal neurotransmission (best investigated with PET).
In order to best study brain function in the above described context it is important that PET and MRI imaging is performed simultaneously, that the time and spatial resolutions of PET and MRI-based imaging are optimally matched and that relevant information can be extracted from multi-parameter data by identifying task-specific most informative combinations of imaging metrics. This talk will describe the development in PET and MRI imaging techniques that was spurred by these requirements, including improvements in imaging instrumentation/performance, introduction of novel image reconstruction approaches, image denoising, data and process modeling, as well as application of data fusion and machine learning approaches to data analysis.
- 12:00 Toru Aoki, Shizuoka University
with K. Takagi, T. Takagi, T. Okunoyama and A. Koike
High count rate CdTe photon counting imaging sensor
We have reported the photon counting imaging sensors by using CdTe compound semiconductor with energy discrimination function. It has good image quality for hard X-ray imaging, but the dynamic range is so low because of its low count late limitation. The pulse width of each pulse generated from each X-ray photon is around several hundred nano-second from 1mm thick of CdTe diode sensor. But the conventional signal processing using charge sensitive amplifier and pulse shaper is so slow around 1μs or more. The dead time is so high in X-ray imaging fluxion condition, it is very difficult to apply X-ray imaging and CT. We developed new count method for high count rate using pulse analysis of rise part by fully high speed digital pulse processor. In this paper, we will report the detail of this method and signal processing LSI. We developed direct current — digital converter by using charge injection method from CdTe X-ray sensor diode. The ASIC include this CD convertors and other digital functions. We will demonstrate X-ray imaging and CT by using this sensor.
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