Publications by authors named "Yeung H"

Purpose: To compare diagnostic accuracy of attenuation-corrected positron emission tomography (PET) with fused PET and computed tomography (CT) in patients with head and neck cancer and to evaluate the effect of PET/CT findings on patient care.

Materials And Methods: Studies of 68 patients were reviewed by two physicians in consensus. Focal fluorodeoxyglucose (FDG) uptake in the head and neck on attenuation-corrected PET images was graded as benign, equivocal, or malignant.

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PET/CT is a new imaging technology that has already found a number of clinical applications in oncologic imaging. Widespread introduction into clinical practice started approximately 2.5 years ago.

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Unlabelled: Recent studies have shown increased artifacts in CT attenuation-corrected (CTAC) PET images acquired with oral contrast agents because of misclassification of contrast as bone. We have developed an algorithm, segmented contrast correction (SCC), to properly transform CT numbers in the contrast regions from CT energies (40-140 keV) to PET energy at 511 keV.

Methods: A bilinear transformation, equivalent to that supplied by the PET/CT scanner manufacturer, for the conversion of linear attenuation coefficients of normal tissues from CT to PET energies was optimized for BaSO(4) contrast agent.

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The aim of the present study is to demonstrate the newly formed tissue in calcium phosphate (Ca/P) ceramics after extra-osseous implantation by histological and immunohistochemistry (IHC) methods. Synthesis porous Ca/P ceramics without adding any growth factor and living cell were implanted in the dorsal muscle of dogs for 1 and 2 months. Undecalcified and decalcified sections were stained by hematoxylin and eosin (H&E), and IHC, respectively.

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Unlabelled: The routine use of PET/CT fusion imaging in a large oncology practice has led to the realization that (18)F-FDG uptake into normal fat and muscle can be a common source of potentially misleading false-positive PET imaging in the neck, thorax, and abdomen. The goal of this study was to characterize this normal variant of (18)F-FDG uptake in terms of incidence and characteristic extent.

Methods: All body scans done on our PET/CT scanners in July and August 2002 were retrospectively reviewed.

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The new combined positron emission (PET)/computed tomographic (CT) scanners have many advantages over PET scanners alone. However, physicians must be aware of the potential artefacts observed in PET/CT scanners. A body PET/CT was performed on an 81-year-old man with colorectal cancer.

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OBJECTIVES: To evaluate the clinical utility of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) in patients with cancer (CA) of the esophagus, and its incremental value over computed tomography (CT) scan.METHODS: Positron emission tomography (PET) scan and CT scan reports of all patients with biopsy-proven CA esophagus from December 1995 to August 1998 were reviewed. PET images were acquired on a high-resolution dedicated PET scanner 45 minutes to 1 hour after intravenous injection of 370 MBq of fluorine-18-fluorodeoxyglucose (F-18-FDG).

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The purpose of this article is to elucidate the role of 2-[18F] Fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) in evaluating patients with head and neck cancer. This will include background information on patient preparation and image acquisition. Normal patterns of uptake will be described in reference to computerized tomography (CT)/magnetic resonance imaging (MRI) to illustrate the relationship of physiology to the anatomic landmarks.

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A 61-year-old non-diabetic woman underwent a non-diagnostic FDG PET study due to ingestion of milk and sugar 150 minutes prior to injection of FDG despite being euglycaemic. A repeat study 2 days later showed 4 pathological foci of FDG uptake, of which only two could be seen retrospectively on the original study. The loss of lesion perspicuity and suppression of FDG uptake in the pathological lesions was corrected by fasting for more than 6 hours.

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OBJECTIVE: Currently available imaging modalities, including CT, ultrasound, and MRI are unsatisfactory in the detection of metastatic gastric cancer, especially lymph node metastases and peritoneal spread. The aim of this study is to evaluate FDG-PET in the diagnosis of primary as well as metastatic gastric cancer.METHOD: All patients (18M/5F; mean age 62, range 33-81) with gastric cancer referred for FDG-PET scan from 1/1/97 to 3/20/98 were studied.

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The goal for this work was to develop a method to determine the feasibility of estimating absorbed dose distribution of I-131 thyroid therapy using I-124 PET images of residual thyroid lesions with the dose constraint of 200 cGy to blood, that is a surrogate for bone marrow toxicity. A dose response study has been carried out on 3 patients with papillary thyroid carcinoma. Those patients were given 15-37 MBq of I-124 along with 74-185 MBq of I-131.

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Metabolic imaging with positron emission tomography (PET) for the staging and monitoring of treatment response has important implications in clinical oncology. The choice of radiotracer is likely to be critically important. The objective of our study was to compare the pharmacokinetics of C-11-methionine with FDG in a group of androgen independent patients with metastatic prostate cancer, to determine the differential metabolism of the two tracers, and to determine the optimal time of imaging after injection in treated and untreated patients.

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"Functional" tumor treatment response parameters have been developed to measure treatment induced biochemical changes in the entire tumor mass, using positron emission tomography (PET) and [F-18] fludeoxyglucose (FDG). These new parameters are intended to measure global changes in tumor glycolysis. The response parameters are determined by comparing the pre- and posttreatment PET-FDG images either visually from the change in image appearance in the region of the tumor, or quantitatively based on features of the calibrated digital PET image.

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This review discusses the technical background of combined PET and CT and considers the clinical applications of PET/CT imaging. Questions addressed include: Is PET/CT superior to PET imaging alone? If so, in which patient populations and in what respect? Can PET/CT imaging affect patient management? Can PET/CT be practiced economically? While much work remains to be done, the available data clearly suggest that PET/CT decreases imaging time per patient and, even for the experienced reader, significantly reduces the number of equivocal PET interpretations. PET/CT also has the ability to improve accuracy of PET image interpretation and to affect clinical decision making, thereby improving patient management.

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Unlabelled: Peritoneal carcinomatosis can be difficult to diagnose, as CT is insensitive, with peritoneal biopsy and lavage often subject to problems of sampling error. The aim of our study was to evaluate the role of (18)F-FDG PET in detecting peritoneal carcinomatosis in patients with stomach, ovarian, and adrenal cancer and mesothelioma and to compare the results with CT scans in the same patient group. Our secondary aim was to identify characteristic patterns of abdominal (18)F-FDG uptake in biopsy-proven peritoneal disease and to correlate these patterns with available histologic and anatomic findings after surgery and structural imaging.

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Stanniocalcin (STC) is a new mammalian polypeptide hormone and appears to be a regulator of neuronal function. We have already shown that the induction of STC mRNA and protein expression by cAMP is integral to neuroblastoma cell differentiation, particularly neurite outgrowth. In this study, we examined the cAMP pathway in greater detail.

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In this article, a method of using Fourier-transform infrared (FTIR) spectrometry to identify four Lyeium barbarum L. (Gouqizi) in turn of colour, shape, taste and water content. The four features (include color is red or black, shape is round or long, quality is dry or wet, taste is sweet or bitter) are related with the FTIR absorption peaks, this is based on the chemical components and their relative contents are different in various Gouqizi.

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A rapid and non-destructive method, was used to identify seven commercial American Ginseng Tea bags by Fourier-transform infrared spectroscopy (FTIR) in this paper. It could be seen from the results, that each sample has its own characteristic infrared spectrum. Also, the seven tea bags could be divided into two groups: one is made from pure Ginseng powders, and the other is made by Ginseng extractives and additives.

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The differential expression of cytochrome P4501A1 gene expression (CYP1A1) in liver, intestine and gill of juvenile tilapia following oral exposure to polychlorinated biphenyl (PCB) Aroclor-1254 or Aroclor-1260 spiked food were investigated. The fish was fed with 0.1 g/g of body weight each day of the spiked food with a concentration of approximately 8 ppm.

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Background: Recently, iterative reconstruction with segmented attenuation corrections (IRSAC) has been introduced for reconstruction of (18)F-FDG PET images. IRSAC produces images that are more pleasing to the eye, but qualitative and quantitative comparisons between IRSAC and filtered back projection (FBP) have not been reported for metastatic cancer. Since quantitative data has been widely used as an adjunct to interpretation of PET scans, comparison between IRSAC and FBP is needed.

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Distraction osteogenesis is a well-established clinical treatment for limb length discrepancy and skeletal deformities. In our previous studies, we have shown that the tension at the distraction gap correlated with the plasma bone specific alkaline phosphatase activity during distraction. Transforming growth factor-beta1 (TGF-beta1) has been shown to have a regulatory role in alkaline phosphatase activity during fracture healing.

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Study Design: Dynamic lumbar flexion-extension motions were assessed by an electrogoniometer and a videofluoroscopy unit simultaneously.

Objective: To develop and validate a new technique for the assessment of lumbar spine motion.

Summary Of Background Data: Spine instability, a clinical condition that is common but difficult to diagnose, has been suggested to involve a characteristic change in the relation between vertebrae during motion.

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Stanniocalcin is a polypeptide hormone that was first reported in fish as a regulator of mineral metabolism. Its recent identification in mammals has opened a new area of investigation in basic and clinical endocrinology. In the present study, regulation of the stanniocalcin (STC) and stanniocalcin related protein (STCrP) genes were investigated in mouse neuroblastoma cells (Neuro-2A) in relation to neuronal cell differentiation.

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We present the case of a 42 year old man, with a history of multiple fractures and generalized pain for two years. A three phase bone scan, demonstrated multiple fractures involving the ribs, both ankles and feet. After going through a battery of tests which included an FDG PET scan (to exclude an occult malignancy), the patient was diagnosed with osteomalacia and hyperparathyroidism.

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