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34
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Introduction
Research Interest:
- Development of medical imaging instruments (Gamma camera, PET, SPECT, CT, etc.): system level development.
Hardware Skills:
- Photodetector: PMT (Hamamatsu), SiPM (SensL, Zecotek, Photonics, Hamamatsu, Excelitas, FBK) APD (RMD, Hamamatsu), SDD (KETEK), etc.
- Scintillator: BGO, LYSO, LSO, LuAP, GSO, NaI(Tl), CsI(Tl), etc.
- Data acquisition units: NIM, CAMAC, CAEN, Lyrtech ADC, etc.
- FPGA development: Xilinx FPGA, Altera FPGA.
Software Skills:
- Matlab/Simulink
- C/C++
- PSPICE
- Labview
- IDL
- GATE simulation
- DETECT2000 simulation
PET/SPECT System Development Experience:
- Animal PET (Clear PET) based on PSPMT coupled with LYSO+LuAP (2007).
- Optical-Gamma dual modality system based on PSPMT and CsI(Tl) (2007).
- Animal SPECT/CT system based on PSPMT and
Publications
Publications (34)
There has been great interest in developing a time-of-flight (TOF) PET to improve the signal-to-noise ratio of PET image relative to that of non-TOF PET. Silicon photomultiplier (SiPM) arrays have attracted attention for use as a fast TOF PET photosensor. Since numerous SiPM arrays are needed to construct a modern human PET, a multiplexing method p...
Recently, we reported a hybrid positron emission tomography-magnetic resonance imaging (PET-MRI) approach involving the transmission of a photo-sensor charge signal to a preamplifier using a long cable. However, in this application, pulse distortions may degrade the performance of the PET detector. The purpose of this study is to further extend the...
Provided is a positron emission tomography (PET) detector module using Geiger-mode avalanche photodiode (GAPD) as a photosensor. The PET detector module includes: a PET detector unit with a scintillation crystal detecting gamma rays emitted from a living body and converting them into a scintillation light and a first GAPD photosensor and a second G...
This paper presents the development of filtering methods for positron emission tomography (PET) signals contaminated by radio frequency (RF) pulses for combined PET and clinical 3-T magnetic resonance imaging (MRI). The filtering methods include software, hardware, and hybrid correction methods. In the software correction method, PET signals are as...
Purpose:
The aim of this study was to develop a prototype magnetic resonance (MR)-compatible positron emission tomography (PET) that can be inserted into a MR imager and that allows simultaneous PET and MR imaging of the human brain. This paper reports the initial results of the authors' prototype brain PET system operating within a 3-T magnetic r...
Disclosed herein is a PET-MRI combination apparatus which can extend transaxial and axial fields of view (FOV) by transmitting an output signal from a photo sensor to the outside of an MRI bore using cable. The PET-MRI combination apparatus includes an MRI bore for capturing an MR image of an object. A PET detector is installed inside imaging space...
In recent times, there has been great interest in the use of Geiger-mode avalanche photodiodes (GAPDs) as scintillator readout in positron emission tomography (PET) detectors because of their advantages, such as high gain, compact size, low power consumption, and magnetic field insensitivity. The purpose of this study was to develop a novel PET sys...
Currently, for most photomultiplier tube (PMT)-based PET systems, constant fraction discriminators (CFD) and time to digital converters (TDC) have been employed to detect gamma ray signal arrival time, whereas anger logic circuits and peak detection analog-to-digital converters (ADCs) have been implemented to acquire position and energy information...
We retrospectively investigated the value of dynamic Tc-diisopropyl-iminodiacetic acid hepatobiliary scintigraphy (HBS) in discriminating postsurgical complications following liver transplantation (LT).
Dynamic HBS was performed for suspected post-LT complications in 201 cases. Hepatic uptake and excretion was visually graded. The portal perfusion...
The new method to correct a parallax error and the loss of coincidence counts caused by the gap between modules was developed for a small animal PET scanner. We proposed the TraPET scanner composed of 6 dual-layer phoswich detector modules. Each detector module consists of a 5.0 mm-thick trapezoidal-shaped monolithic LSO crystal and a 23 x 23 array...
Recently, we have reported the approach of transmitting photo-sensor charge signal to preamplifier using long cable for development of hybrid PET-MRI. However, pulse distortions degrading the performance of PET detector might occur in this approach. The purpose of this study is to develop a pulse restoration circuit (PRC) compensating the performan...
A PET employing Geiger-mode avalanche photodiode (GAPD) has been designed and developed in our laboratory for simultaneous human brain PET-MR imaging. The purpose of this study is to evaluate the effect of temperature on the performance of the brain PET. The PET gantry including LYSO and GAPD array were placed in a temperature controlled chamber. A...
This study introduces a depth-encoding PET detector inserting a glass plate between the pixilated scintillation crystal layers. The principle of proposed design was that the relative amount of light received by each photosensor would be altered by using the glass plate and this change in the light distribution could generate the pattern diagram of...
Positron emission tomography (PET) employing Geiger-mode avalanche photodiodes (GAPDs) and charge signal transmission approach was developed for small animal imaging. Animal PET contained 16 LYSO and GAPD detector modules that were arranged in a 70 mm diameter ring with an axial field of view of 13 mm. The GAPDs charge output signals were transmitt...
The use of a dual-ended readout PET detector module based on Geiger-mode avalanche photodiodes (GAPDs) with large-area microcells was proposed to obtain high photon detection efficiency (PDE) and overcome energy non-linearity problems. A simulation study was performed and experimental measurement were taken for the single- and dual-ended PET detect...
We examined a PET detector consisting of an LYSO array coupled to a 4 × 4 array of large-size Geiger-mode avalanche photodiode (GAPD). The GAPD coupled to 3 mm × 3 mm × 20 mm LYSO pixel crystal has been investigated for possible use as an MR-compatible PET photosensor. Primary characteristics of a PET detector, such as energy resolution and coincid...
The authors have previously reported a simulation study on a novel multi-pinhole (MP) collimator that is able to provide improved angular sampling and an enlarged imaging field of view (FOV) when compared to a low-energy high-resolution parallel-hole (LEHR) collimator using a detector of equivalent size. The aim of this study was to develop a minia...
Light sharing PET detector configuration coupled with thick light guide and Geiger-mode avalanche photodiode (GAPD) with large-area microcells was proposed to overcome the energy non-linearity problem and to obtain high light collection efficiency (LCE). Theoretical evaluations were performed for 90 types of PET detector modules. A Monte Carlo simu...
A dual-ended readout PET detector module based on Geiger-mode avalanche photodiode (GAPD) with large-area microcells was proposed to obtain high photon detection efficiency (PDE) and to overcome the energy non-linearity problem. Theoretical analysis and experimental measurement were performed for the single- and dual-ended PET detector modules whic...
We have previously reported that a brain PET using GAPD arrays was successfully developed. The brain PET consisted of 72 4 × 4 GAPD arrays combined with LYSO crystals (single pixel size: 3 mm × 3 mm). Each 4 GAPD arrays' output signals were sent to a 64:1 position decoder circuit (PDC) which detects the fastest gamma signal of 64 input channels. To...
Statistically based iterative algorithms such as maximum likelihood-expectation maximization (ML-EM) are used for image reconstruction in single photon emission computed tomography (SPECT). Unmatched projector/backprojector pairs are sometimes used to accelerate the iteration process in the reconstruction algorithm. In this work, we propose and exp...
A new positron emission tomography (PET) detector signal processing method, the charge signal transmission approach, is proposed for the development of a hybrid PET-magnetic resonance imaging (MRI). A number of experiments were performed to demonstrate that the Geiger-mode avalanche photodiode (GAPD) charge output could be transmitted to a preampli...
A simple and improved digital timing method was developed for positron emission tomography (PET). This method, the so-called ‘initial rise interpolation method’, is based on an important characteristic of gamma signals: a properly pre-amplified and sampled gamma signal pulse can be characterized to arrive with an initial rise from the baseline and...
The aim of this study is to develop a MR compatible PET that is insertable to MRI and allows simultaneous PET and MR imaging of human brain. The brain PET having 72 detector modules arranged in a ring of 330 mm diameter was constructed and mounted in a 3-T MRI. Each PET module composed of 4 × 4 matrix of 3 mm × 3 mm × 20 mm LYSO crystals coupled to...
Use of channel reduction techniques that reduce the number of signals transmitted to a data acquisition (DAQ) module can lead to more efficient use of the DAQ module for PET with numerous readout channels. The purpose of this study was to develop a position decoder circuit (PDC) with a capacity to output the digital address and analog pulse of one...
Geiger-mode avalanche photodiode (GAPD) has been demonstrated to be a high performance PET sensor because of high gain, fast response, low excess noise, low bias voltage operation and magnetic field insensitivity. The purpose of this study is to develop a PET for human brain imaging using 4 ? 4 array of large size GAPD. PET detector modules were de...
We had previously reported a simulation study on a multi-pinhole collimator (MP) having lead vertical septa which could provide improved angular sampling and enlarged imaging field of view (FOV) compared to low energy high resolution parallel-hole collimator (LEHR) using same size detector. The aim of this study was to develop a miniature SPECT to...
The aim of this study is to develop a MR compatible PET that is insertable to MRI and allows simultaneous PET and MR imaging of human brain. The brain PET having 72 detector modules arranged in a ring of 330 mm diameter was designed. Each PET module composed of 4 ? 4 matrix of 3 mm ? 3 mm ? 20 mm LYSO crystals coupled to a tileable 4 ? 4 array Geig...
A Geiger-mode avalanche photodiode (GAPD) array-based MRI compatible PET is being developed in our laboratory. The purpose of this study is to develop filtering methods for PET event signals contaminated by RF pulses for simultaneous PET-MR imaging. The detector for the MRI compatible PET was composed of LYSO scintillators coupled with GAPD arrays....
The purpose of this study is cross-compatibility of PET and MRI was characterized to explore the optimal method overcoming possible interferences between them. MR phantom images were acquired by placing the PET components inside and outside RF-coil in 7-T MRI to examine the effect of the relative position of PET detector and RF-coil on MRI. Theoret...
A PET data acquisition (DAQ) system based on multiple high-speed, 8-channel DAQ cards is being developed. Each of these DAQ cards has 8-channel 14-bit 100 MHz simultaneous ADCs, a six million-gate FPGA with 104 MHz onboard clock and a 16-bit 128 MB SDRAM. The SDRAM has a data transfer bandwidth of 450 MB/S, thus for raw data acquisition, only two c...
A simple and improved digital timing method has been developed for positron emission tomography (PET). The so-called initial rise interpolation method is based on an important characteristic of gamma signal: a properly pre-amplified and sampled gamma signal pulse can be characterized to arrive with an initial rise from baseline and then to go up wi...
This review introduces advances in clinical and pre-clinical single photon emission computed tomography (SPECT) and positron emission tomography (PET) providing noninvasive functional images of biological processes. Development of new collimation techniques such as multi-pinhole and slit-slat collimators permits the improvement of system spatial re...