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This paper describes the methodology and the evaluation of a 3D skeletonization algorithm applied on brain vascular structure. This method is based on the application of the minimum cost-spanning tree using Dijkstra's algorithm and seems well appropriate to tubular objects. We briefly describe the different steps, from the segmentation to the skeleton analysis. Besides, we propose an original evaluation...
This study investigated the effects of mobile-phone-type radiation on the cerebral activity of seizure-prone animals. The experimental set-up used in this research for exposure of small animals to radiofrequency standing waves allows direct measurement of the power absorbed by the animal. Essentially, the setup consists of a metallic box containing an antenna and experimental animal immobilized in...
The method of utilizing available prior information in the popular FCM algorithm and assesses its benefits in estimating the intensity inhomogeneities and segmenting human brain MRI volumes is studied in this paper. The intensity inhomogeneities in medical images are associated with the acquisition sequences and imperfections in the radio-frequency coils in MRI scanners. Presence of intensity inhomogeneities...
This paper demonstrates the usefulness of a classifier based on a subspace distance for the detection of bleeding stroke based on microwave scattering measurements from an antenna array placed around the skull. This discriminating classifier is suitable for high dimensional data applications when the number of training data samples is less than the data dimension. The proposed classifier was tested...
In this paper, we are presenting a framework for investigation on mobile phone and human head interaction. As we all know that some of the radio waves emitted by a mobile phone handset are absorbed by the human head. The rate at which radiation is absorbed by the human body is measured by the Specific Absorption Rate (SAR). The SAR is calculated by using Finite Difference Time Domain (FDTD) Method...
Information on biological tissues for medical diagnoses can be usually provided by X-ray images, ultrasonic images and MRI, which offer basically the information on mass or proton density distributions. On the other hands, electrical bioimpedances contain different information related to tissue structures and their physiological states and functions. It is well known that the electrical properties...
Intrinsic optical signal (IOS) indicates activities of cerebral cortical neurons in the optical imaging method, which is one of the in vivo recording methods of activities of cerebral cortical neurons. We propose the IOS imaging method for craniotomy procedure such as diagnostic use of epilepsy surgery. We designed a prototype CMOS image sensor device using 0.35-??m CMOS standard process for in vivo...
Truncated data problems are encountered in computed tomographic (CT) scanning scenarios where it is desirable to restrict the radiation dosage to a region-of-interest (ROI) of the object cross-section being imaged. In this paper, we propose a new image reconstruction technique for handling truncated data based on projection data extrapolation using a non-stationary time-series modeling approach. A...
In the standard software for the Siemens HRRT PET scanner the most commonly used segmentation in the ??-map reconstruction for human brain scans is MAP-TR. Problems with bias in the lower cerebellum and pons in HRRT brain images have been reported. The main source of the problem is poor bone / soft tissue segmentation in these regions and the lack of scatter correction in the ??-map reconstruction...
SiliSPECT, a multi-pinhole, multi-detector SPECT system, was designed to image targeted-regions of rodents at sub-300 ??m resolution with motionless data acquisition and a special reconstruction method. High spatial resolution is achieved with thick silicon double-sided strip detectors (DSSDs) and 250 ??m pinhole apertures. Each of the two heads contains two stacked DSSDs, which improves total detection...
Volume-of-interest (VOI) segmentation is an important prerequisite for quantitative analysis of structure and function in multimodal tomographic images (e.g., MRI, CT, PET, SPECT images) of humans and small animals. A suitable VOI segmentation method should allow user interaction to position the VOI where desired and be automated to support the user as much as possible. Thus, semiautomatic methods...
We designed a concept of high resolution and quantitative SPECT for imaging a selected small region-of-interest (ROI) of human brain. This system is aimed at achieving high resolution less than 1 mm and being applied for imaging neurons and evaluating drug delivery system. Pinhole or cone-beam collimators are useful for high-resolution imaging of small ROI. However, when the ROI is smaller than the...
Certain neurological disorders such as Parkinson's disease are diagnosed by imaging centrally located brain structures such as basal ganglia and striatum. High sensitivity imaging of these structures is essential for the early-stage diagnosis of the disorder. We simulated a multi-geometric collimator that combines a short-focal-length astigmatic half-cone-beam collimator, designed to efficiently image...
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 designed and built to develop a prototype PET. The PET...
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 Geigermode avalanche photodiode (GAPD) and designed to...
With the advance of new technology, PET systems nowadays have much higher sensitivities than before with the adoption of faster scintillators, faster electronics, larger solid angle detectors and full 3D data collection mode. All of these lead to the increasing of the random coincidences that will affect the image quality. Accurate random correction is important for the quantitative imaging in PET...
Task-based assessment of image quality is a challenging but necessary step in evaluating advancements in PET instrumentation, algorithms, and processing. We have been developing methods of evaluating observer performance for detecting and localizing focal warm lesions using experimentally-acquired whole-body phantom data designed to mimic oncologic FDG PET imaging. This work describes a new resource...
A promising approach in PET image reconstruction is to incorporate high resolution anatomical information (measured from MR or CT) taking the anato-functional mutual information (MI) or its joint entropy (JE) as the prior. The MI or JE of the images only classify voxels based on intensity, while neglecting structural spatial information. In this work, we have implemented an anatomy assisted MAP-EM...
The High-resolution Oncologic Transformable PET (HOTPET) camera has intrinsic spatial resolution of better than 3 mm and can operate in different modes including the whole-body mode and brain mode. In the whole-body mode, HOTPET has a transverse field-of-view (FOV) of 60 cm and an axial FOV of 13 cm. In the brain mode it has a transverse FOV of 39 cm and an axial FOV of 21 cm. The purpose of this...
The ECAT High Resolution Research Tomograph (HRRT) (CTI PET Systems, Knoxville, TN, USA) is the state-of-the-art positron emission tomography (PET) scanner in the nuclear medicine imaging field. The gantry of the HRRT PET scanner has detector-free regions. These regions between the detector blocks introduce missing parts to the acquired PET data. Without the estimation of the missing parts of the...
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