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Positron emission tomography - computed tomography (PETCT) is now accepted as the best imaging technique to accurately stage lung cancer. The consistent and accurate interpretation of PET-CT images, however, is not a trivial task. We propose a content-based image retrieval system for retrieving similar cases from an imaging database as a reference dataset to aid the physicians in PET-CT scan interpretation...
Quantitative PET is essential for reliable and consistent diagnostics as well as for proper clinical image interpretation. It has been demonstrated that in co-registered dual-modalities, anatomical data can improve functional images by way of synergistic enhancement. We propose a practical method for PET-CT enhancement by functional to anatomical image adaptation based on 'correlated nonlinear diffusion'...
X-ray CT images have various applications, including CT-based attenuation correction (CTAC) for PET. Low-dose CT imaging is particularly desirable for CTAC. Dual-energy (DE) CT imaging methods may improve the accuracy of attenuation correction in PET. However, conventional DE CT approaches to sinogram material decomposition use logarithmic transforms that are sensitive to noise in low-dose scans....
Content-based image retrieval (CBIR) has been an active research area since mid 90's with major focus on feature extraction, due to its significant impact on image retrieval performance. When applying CBIR in the medical domain, different imaging modalities and anatomical regions require different feature extraction methods that integrate some domain-specific knowledge for effective image retrieval...
PET and CT image registration is an important tool of clinical diagnosis of diseases. For PET and CT images, a preprocessing algorithm of medical image registration is proposed in this paper. The algorithm process includes image normalization, CT image adaptive threshold adjustment and automatic extraction of tissues based on morphology, edge detection and statistical analysis theory, and improved...
The integration of patient digital photographic images with medical imaging studies can serve as a powerful identification tool and prevent medical errors. Photographs can also provide supplemental clinical information that can improve diagnosis. Digital cameras can easily and inexpensively be incorporated in all medical imaging devices such that point-of-care photographs can be obtained along with...
Objective: Simultaneous positron emission tomography/magnetic resonance (PET/MR) acquisition with the Siemens BrainPET employs a transmit/receive coil that fits concentrically within the system's PET insert. The coil is transparent in MR but visible in the PET FOV and occupies space between the patient and PET detectors. This work develops an estimate of the coil position within the BrainPET FOV and...
Allowing the early detection of metabolic changes during treatment, Positron Emission Tomography (PET) is a promising tool for therapy response assessment. A therapeutic response is usually defined as variations of semi-quantitative parameters such as standardized uptake value (SUV) measured in PET scans performed during the treatment. However, this approach does not take into account volume variation...
Accurate attenuation correction in PET/CT relies upon an anatomically matched PET and CT. Respiratory motion introduces attenuation mismatch because the PET and CT scans are not necessarily temporally correlated. Acquiring a 4DCT scan in which each frame of the 4DCT is matched with a frame in a 4D gated PET is one strategy for obtaining temporally correlated PET and CT frames. In this paper we propose...
This paper presents the system design and engineering of a lower-cost, large axial field-of-view micro PET-CT (MuPET) for small animal imaging. The system has been constructed and being tested. 30,420 LYSO detectors (1.25 transaxial × 1.4 axial × 10 mm3) form a 16.5-cm detector solid ring and a large 11.6-cm axial field for high detection sensitivity. The 30240 crystals are configured into 180 pentagon-shaped...
We describe the use of relatively low-cost GPU-based processors to implement iterative MAP (Maximum a Posteriori) PET image reconstruction. The algorithm combines accurate system modeling using a factored matrix approach with a preconditioned conjugate gradient method. We describe the procedures used to parallelize the algorithm including use of data reordering schemes and partitioning of calculations...
Respiratory motion causes different magnitude qualitative and quantitative artefacts in medical imaging and especially in emission tomography. Solutions presented to date include respiratory synchronized PET and CT acquisitions. In order to increase the signal to noise ratio of the synchronized images the use of non-rigid transformations during the reconstruction process accounting for the respiratory...
A collimation device for 511 keV small animal SPECT/CT using clinical detectors was investigated as an alternative to dedicated PET/CT. The device consists of a 45 mm thick collimator (lead cylinder with 30 tungsten pinhole inserts) and an animal bed with three-degrees-of-freedom. The device rests on the patient bed of a clinical SPECT/CT scanner, where the gamma cameras rotate around the collimator...
An ultra-resolution high-sensitivity preclinical PET/CT - MuPET is designed and manufactured. The detector system is a triacontagon shape which is very close to a perfect cylindrical ring. The inner diameter of the ring is 165 mm and the axial length is 116 mm. The detector system is using 180 PMT-quadrant-sharing (PQS) blocks - 30 blocks per ring and 6 rings axially with 210 low-cost round PMTs for...
An efficient, two-dimensional, analytic, Spline Reconstruction Technique (SRT) has been presented earlier in the literature. This technique involves the Hilbert transform of the sinogram which is approximated in terms of natural cubic splines. The aim of this study is to evaluate the SRT algorithm using Monte-Carlo simulated sinograms and real PET data, in comparison with three commonly used reconstruction...
In this article, methods are described which help move the concept of continuous bed motion (CBM) for TOF PET (i.e. for PET/CT applications) out of the realm of list-mode-only research and into everyday clinical usage. Long proposed for PET, CBM moves the patient horizontally (at a more or less steady rate) through the PET FOV during the acquisition and offers several points of advantage over the...
We have developed an image registration approach for longitudinal liver PET studies using the anatomical information in two sets of associated four phase CT images. We first used the level set method to segment the whole liver in the venous phase CT image. We then applied a non-rigid mutual information based method to register the two venous phase liver images. In our data acquisition protocol, the...
We present a detailed description of an algorithm to detect the Mid-sagittal Line (MSL) in the human brain CT. The method seeks the line with respect to the image maximum symmetry. Our method relies on the moving window to define the counterpart points between both sides of the brain with the symmetry line. The matching points are measured by the adaptive weighted mutual information based on local...
Objective The aim of this study was to explore the clinical value of the combination of prior knowledge of physicians and texture features for differentiation of malignant from benign solitary pulmonary nodules(SPNs) and mass lesions based on 18F-FDG PET/CT. Methods 143 patients with known solitary pulmonary nodule or mass were enrolled in the study. All the patients underwent 18F-FDG PET/CT examination...
PET/CT medical image fusion has important clinical significance. As the multiwavelet transform has several particular advantages in comparison with scalar wavelets on image processing, this paper proposes a medical image fusion algorithm based on multiwavelet transform after in-depth study of wavelet theory. The algorithm achieves PET/CT fusion with wavelet coefficients fusion method. Experimental...
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