Design procedure for a high resolution electron microscope objective lens.

BACKGROUND: Flow cytometry is the standard method for the multi-parametric analysis of cells. However, for about a decade, an instrument has been available which analyses fluorescing cells immobilised on slides called a laser scanning cytometer (LSC). Its design, according to the principles of slide-based cytometry, promises many advantages, especially in the analysis of minimal sample volumes. METHODS AND PATIENTS: To date, applications for cultured cells and animal models have been established. Its use for clinical purposes, however, remains to be critically evaluated. We analysed a variety of specimens obtained in our clinical routine. RESULTS: First, the instrument's resolution was evaluated using standardised particles. This showed a very good sensitivity across a wide range of fluorescence intensities at various wavelengths. Next, diverse applications for tissue engineering, immunophenotyping, and ENT-oncology were tested. Considering its microanalytical capacities, LSC proved to be a convincing tool for clinical use. Additionally, complex structures such as bi-layers of cultured cells were analysed. CONCLUSION: A broad spectrum of applications in clinical practice and research for the LSC is evident.

Equipment Design↗

PubMed2005

Development of a multi frequency pulse diagnostic ultrasound device.

Diagnostic ultrasound is a powerful tool for characterising a wide range of solutions, with devices such as the continuous wave Malvern Ultrasizer at the forefront. However to reduce capital cost and allow online application without reducing accuracy and application a new system was designed, built and made operational. The ultrafood system is a variable path length pulse system, which produces both time and frequency domain data that is repeatable and accurate compared to reference methods and values. The use of multiple distance measurement removes the need for reference fluid calibration and thermal expansion compensation.

Equipment Design↗

PubMed2005

Development of a portable 3D ultrasound imaging system for musculoskeletal tissues.

3D ultrasound is a promising imaging modality for clinical diagnosis and treatment monitoring. Its cost is relatively low in comparison with CT and MRI, no intensive training and radiation protection is required for its operation, and its hardware is movable and can potentially be portable. In this study, we developed a portable freehand 3D ultrasound imaging system for the assessment of musculoskeletal body parts. A portable ultrasound scanner was used to obtain real-time B-mode ultrasound images of musculoskeletal tissues and an electromagnetic spatial sensor was fixed on the ultrasound probe to acquire the position and orientation of the images. The images were digitized with a video digitization device and displayed with its orientation and position synchronized in real-time with the data obtained by the spatial sensor. A program was developed for volume reconstruction, visualization, segmentation and measurement using Visual C++ and Visualization toolkits (VTK) software. A 2D Gaussian filter and a Median filter were implemented to improve the quality of the B-scan images collected by the portable ultrasound scanner. An improved distance-weighted grid-mapping algorithm was proposed for volume reconstruction. Temporal calibrations were conducted to correct the delay between the collections of images and spatial data. Spatial calibrations were performed using a cross-wire phantom. The system accuracy was validated by one cylinder and two cuboid phantoms made of silicone. The average errors for distance measurement in three orthogonal directions in comparison with micrometer measurement were 0.06+/-0.39, -0.27+/-0.27, and 0.33+/-0.39 mm, respectively. The average error for volume measurement was -0.18%+/-5.44% for the three phantoms. The system has been successfully used to obtain the volume images of a fetus phantom, the fingers and forearms of human subjects. For a typical volume with 126 x 103 x 109 voxels, the 3D image could be reconstructed from 258 B-scans (640 x 480 pixels) within one minute using a portable PC with Pentium IV 2.4 GHz CPU and 512 MB memories. It is believed that such a portable volume imaging system will have many applications in the assessment of musculoskeletal tissues because of its easy accessibility.

Equipment Design↗