Whole-body [18F]FDG PET in the management of metastatic brain tumours

BACKGROUND: To determine its roles in the diagnosis and the systemic evaluation of metastatic brain tumours, whole-body positron emission tomography (PET) using [18F]FDG was performed in 20 consecutive patients. METHODS: All patients were thought to be suffering or needing to be differentiated from metastatic brain tumours. Nine patients had multiple brain lesions; six were older and showed a rim-enhancing lesion with surrounding oedema; seven had homogeneously enhancing periventricular lesion(s) on computed tomography (CT) and/or magnetic resonance (MR) imaging, thought to be central nervous system lymphomas. Two patients had skull mass(es) and two patients had a solid mass suspected to be, respectively, a haemorrhagic metastasis and a metastatic malignant melanoma. All of them received whole-body [18F]FDG PET and conventional systemic work-up for metastasis in order to compare the results of the two methods. RESULTS: Metastatic brain tumours were diagnosed on whole-body [18F]FDG PET in eleven patients who had extracranial and intracranial hypermetabolic lesions. In nine of these, a conventional work-up also detected primary lesions which on whole-body [18F]FDG PET were seen to be hypermetabolic foci. Systemic lymph node metastases were detected by whole-body [18F]FDG PET only in two patients and histological diagnosis was possible by biopsy of lymph nodes rather than of brain lesions. In the remaining nine patients who had only intracranial hypermetabolic foci, histological diagnosis was made by craniotomy or stereotactic biopsy. It was confirmed that seven of nine patients were suffering from a primary brain tumour and two from metastatic carcinoma. None of the nine showed evidence of systemic cancer on conventional work-up. Histological diagnoses of the primary brain tumours were four cases of primary central nervous system lymphoma and one each of multifocal glioblastoma, Ewing's sarcoma, and cavernous angioma. Patients felt no discomfort during the whole-body [18F]FDG PET procedure and there were no complications. The false negative rate in [18F]FDG PET and in conventional work-up was 15.4% and 30.7% respectively. There were no false positives on either [18F]FDG PET or conventional work-up. CONCLUSION: It is suggested that whole-body [18F]FDG PET is a safe, reliable, and convenient method for the diagnosis and systemic evaluation of patients thought to be suffering or needing to be differentiated from a metastatic brain tumour.     

Development of core mode blocker with H/sub 2/-loaded Ge-B codoped fibres

A novel fabrication method of the core mode blocker by exposing H/sub 2/-loaded Ge-B codoped fibres to local electric arc discharge for application to the LPFGs-based tunable all-fibre bandpass filter with 6.5 nm bandwidth and 40 nm tuning range is presented.     

Expanding an existing multiple choice test with a mixed format test: simulation study on sample size and item recovery in concurrent calibration

When a new set of mixed format items is augmented with a previous old multiple-choice (MC) test, those mixed format items should be linked to the existing old MC test. This study used simulation to investigate sample size effect on recovery of known item parameter from the concurrent calibration in the context of horizontal equating, where the new mixed format tests are equated to the existing MC test which acts as the common linking items. In the partial credit model following the Andrich style parameterization, item location and item step parameters were differentially affected by the sample size. Item location parameters were recovered better than item step parameters at the individual item, the sub-test, and the total test level. This study also shows the outward bias for the item location parameter estimated by the maximum likelihood estimator.     

Effective Thermal Conductivity and Permeability of Aluminum Foam Materials1

An experimental measurement program was performed to determine thermophysical properties of aluminum-based foam metals. The effective thermal conductivity k _e and permeability K were investigated in detail. Experimental facilities were fabricated, and the measurement procedures and methodologies were evaluated. One-dimensional heat conduction was considered to determine k _e . The results indicate that k _e increases as the porosity decreases. However, no noticeable changes in k _e were detected from variations of the cell size of the foam metal at a fixed porosity . The permeability K is substantially affected by both and the cell size. An empirical correlation for the friction factor f is proposed based on the concepts of K and inertial effect.     

STEELEX: A coupled expert system for integrated design of steel structures

Most expert systems developed so far are concerned with symbolic processing of a knowledge base. Solution of complex engineering problems often requires substantial numerical processing in addition to symbolic processing of heuristics and experiential knowledge. In this paper, we present STEELEX, a prototype knowledge-based expert system for integrated design of building structures consisting of moment-resisting steel frames. STEELEX is a coupled system in which AI symbolic processing is combined with conventional numerical processing. STEELEX produces the final detailed design including the beam-column connections ready for fabrication. In addition, it can explain the basis of design and the principles behind the design specification. STEELEX has been developed using a domain-specific tool called SDL (for Structural Design Language). Implemented in the INTERLISP environment, SDL provides a design problem-solving environment using a hierarchical cooperating specialists paradigm. STEELEX has a debugging facility and provides a multiwindow graphics interface for drawing isometric as well as orthographic views of the steel frame and beam-column connections.     

Developing a custom DSP for vision based human computer interaction applications

Multimedia Tools and Applications - As the computing power of modern devices become greater, computer vision is increasingly adopted as the means of human-computer interaction. The industry is...     

Enhanced brightness and efficiency of organic light-emitting diodes with an LiF in the Alq/sub 3/

Highly efficient and bright organic light-emitting diodes have been realized by inserting a thin insulating lithium fluoride (LiF) layer in the tris-(8-hydroxyquinoline) aluminum (Alq/sub 3/) with conventional organic layers. By comparing the performances of newly devised devices as a function of the position of the LiF in the Alq/sub 3/ layer, the authors propose the optimal position of the LiF in the Alq/sub 3/ layer. Experimental results show that the efficiency and brightness of the newly devised device with LiF in the Alq/sub 3/ layer were seven times higher than that without LiF in the Alq/sub 3/ layer.     

Silica-coated dual-tube zirconia induction furnace for high-strength optical-fibre production

The dual-wall zirconia induction furnace consists of an inner susceptor tube and an outer insulation tube. The centre piece of the inner tube is coated with a thin silica film. The performance of the newly designed furnace was evaluated in terms of the strength of drawn fibres. The proof test of 47 km length of fibre demonstrated superb strength results, yielding the average survival length at 1·4 GN/m2 (200 klb in?2) to be ~8 km.