Detector concept for OPET-a combined PET and optical imaging system

Prout, David; Silverman, Robert W.; Chatziioannou, Arion F.

doi:10.1109/tns.2004.829736

Cited by 53 publications

(27 citation statements)

References 12 publications

(2 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On the clinical side, efforts have been made to improve image quality using time of flight PET [1] and by developing improved algorithms for scatter and attenuation correction, image reconstruction, and motion correction [2, 3]. On the preclinical side, the main focus is to improve the spatial resolution and sensitivity of the PET scanners [4-6] as well as to develop multimodality systems that combine PET with magnetic resonance imaging [7-10], x-ray computed tomography [11], and optical imaging [12]. In current small animal PET scanners, a compromise between sensitivity and spatial resolution is made due to the depth of interaction (DOI) effect.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Depth of Interaction Encoding for a Pixelated LSO Array With a Single Multi-Channel PMT

Yang

Cherry

2009

IEEE Trans. Nucl. Sci.

View full text Add to dashboard Cite

A new approach to depth of interaction (DOI) encoding for a pixelated LSO array using a single multi-channel PMT was investigated. In this method the DOI information was estimated by taking advantage of optical crosstalk between LSO elements and examining the standard deviation (spread) of signals on all channels of the PMT. Unpolished and polished 6×6 LSO arrays with a crystal size of 1.3×1.3×20 mm 3 were evaluated on a Hamamatsu H7546 64-channel PMT. The arrays were placed on the center of the PMT and the central 16 channels of the PMT were individually read out and digitized. For the unpolished array, all crystals were resolved in the flood histogram. An average DOI resolution of 8 mm was obtained. The energy resolution was ∼25% after the signal amplitude was corrected using the measured DOI information. For the polished array, the flood histogram was superior to the unpolished array, however no DOI information could be measured. Using unpolished crystals, this method could be a practical way to achieve limited DOI information in PET detectors. The standard deviation of all PMT channels can be readily obtained using a resistor network. Only five signals (four signals to determine the x-y position and one signal measuring the standard deviation) need to be digitized, and this method only requires a single photon detector to read out the array. Unlike phoswich detectors, the method does not require segmenting the scintillator array into layers. The measured DOI resolution was much worse than that obtained with the dual-ended readout method, however, it was similar to that obtained with a two-layer phoswich detector. KeywordsPositron emission tomography (PET); depth of interaction; small-animal imaging

show abstract

Section: Introductionmentioning

confidence: 99%

Investigation of Depth of Interaction Encoding for a Pixelated LSO Array With a Single Multi-Channel PMT

Yang

Cherry

2009

IEEE Trans. Nucl. Sci.

View full text Add to dashboard Cite

show abstract

“…The diffusion equation is used to determine the balance intensities for internal sources N S for the surface element in a single voxel. If the position of the light source exceeds the maximum detectable depth (Zdet –see Flowchart on Figure 5) we need to use a more sophisticated method to obtain source coordinates estimates (FEM [25], Monte Carlo [18]), or use a priori information obtained from another imaging system (CT, MRI or OPET [26]). Step 2 For each voxel j determines an initial order approximation

φ_{j}^{0}

(i.e. initial guess as an input image, which contains all diffuse light information) using the solution for photon fluence:

ϕ_{j}^{0} = {false(ρ \otimes ϕ + \hat{n} false)}_{j} ≅ \frac{1}{\sum_{i = 1}^{I} x_{i j} p_{i}^{t}} \sum_{i = 1}^{I} x_{i j} p_{i}^{0} \sum_{s = 1}^{s = N_{s}} S_{o}^{'} exp false(- μ_{eff} r_{j s} false) / r_{j s}

where μ eff = (μ a / D ) 1/2 .…”

Section: Methodsmentioning

confidence: 99%

Semi-automated Image Processing for Preclinical Bioluminescent Imaging

Slavine

McColl

2015

J Appl Bioinform Comput Biol

View full text Add to dashboard Cite

Objective Bioluminescent imaging is a valuable noninvasive technique for investigating tumor dynamics and specific biological molecular events in living animals to better understand the effects of human disease in animal models. The purpose of this study was to develop and test a strategy behind automated methods for bioluminescence image processing from the data acquisition to obtaining 3D images. Methods In order to optimize this procedure a semi-automated image processing approach with multi-modality image handling environment was developed. To identify a bioluminescent source location and strength we used the light flux detected on the surface of the imaged object by CCD cameras. For phantom calibration tests and object surface reconstruction we used MLEM algorithm. For internal bioluminescent sources we used the diffusion approximation with balancing the internal and external intensities on the boundary of the media and then determined an initial order approximation for the photon fluence we subsequently applied a novel iterative deconvolution method to obtain the final reconstruction result. Results We find that the reconstruction techniques successfully used the depth-dependent light transport approach and semi-automated image processing to provide a realistic 3D model of the lung tumor. Our image processing software can optimize and decrease the time of the volumetric imaging and quantitative assessment. Conclusion The data obtained from light phantom and lung mouse tumor images demonstrate the utility of the image reconstruction algorithms and semi-automated approach for bioluminescent image processing procedure. We suggest that the developed image processing approach can be applied to preclinical imaging studies: characteristics of tumor growth, identify metastases, and potentially determine the effectiveness of cancer treatment.

show abstract

“…It has about 20% quantum efficiency for 400 nm wavelength and 6% for 600 nm wavelength ( Fig.2-d)). For the scintillation crystal, we use Gd 2 SiO 5 (GSO) because it has a short scintillation decay time and shows no self radiation [1]. GSO crystals are cut in 1.42 mm x 1.42 mm x 4.5 mm and chemically etched.…”

Section: Methodsmentioning

confidence: 99%

Preliminary study of a DOI-PET detector with optical imaging capability

Takahashi

Inadama²,

Murayama³

et al. 2007

2007 IEEE Nuclear Science Symposium Conference Record

View full text Add to dashboard Cite

Positron emission tomography (PET) and optical imaging are two major techniques for molecular imaging. The PET scanner which enables simultaneous detection of optical imaging will be a powerful tool in molecular imaging. Here, we propose a new detector that detects both signals: annihilation photons for PET and photons for optical imaging.It is based on a four layered depth-of-interaction (DOI) PET detector. Since the detector must be set at a close distance to an object for optical imaging, the DOI information becomes important to obtain uniform spatial resolution in PET imaging over the field-of-view. The proposed PET/Optical imaging detector consists of a scintillation crystal block and a position sensitive photo multiplier tube (PS-PMT). While the bottom of the crystal block is optically coupled to the PS-PMT, four side surfaces of the crystal block are covered with reflectors. A dichroic mirror is placed on the top of the crystal block. The dichroic mirror allows fluorescence photons (longer wavelength than 600 nm) to pass through while it reflects scintillation photons (wavelength around 450 nm) generated within the crystal block. Owing to the dichroic mirror, both scintillation photons originating inside the crystal block and fluorescence photons coming from outside the block can be detected by the same PS-PMT. To evaluate of the DOI-PET/Optical detector, we first measured the influence of the dichroic mirror. The results show that the dichroic mirror maintains DOI-PET detector performance without significant loss of fluorescence photons for optical imaging.

show abstract

Detector concept for OPET-a combined PET and optical imaging system

Cited by 53 publications

References 12 publications

Investigation of Depth of Interaction Encoding for a Pixelated LSO Array With a Single Multi-Channel PMT

Investigation of Depth of Interaction Encoding for a Pixelated LSO Array With a Single Multi-Channel PMT

Semi-automated Image Processing for Preclinical Bioluminescent Imaging

Preliminary study of a DOI-PET detector with optical imaging capability

Contact Info

Product

Resources

About