Technology and Health Care - Volume 7, issue 1

Authors: Maylia, Eric | Nokes, Leonard D.M.

Article Type: Research Article

Abstract: Ultrasonic testing of bones has been used with varying degrees of success for more than 40 years to determine mechanical properties of bone tissue and strength of whole bones. Ultrasound has also been used in an effort to develop non-invasive techniques for monitoring fracture healing in long bones. Despite early promising results, clinically useful methods have yet to be developed. This paper provides a comprehensive review of the literature of determining mechanical properties of bone and the monitoring of fracture healing.

DOI: 10.3233/THC-1999-7101

Citation: Technology and Health Care, vol. 7, no. 1, pp. 1-28, 1999

Authors: Schubert, J.K. | Esteban-Loos, I. | Geiger, K. | Guttmann, J.

Article Type: Research Article

Abstract: Using the volatile anaesthetic isoflurane as a marker substance a gas chromatographic method for analysis of exhaled gas in mechanically ventilated patients was evaluated. Twelve patients with and 10 patients without preceding isoflurane exposure and seven blank respiratory circuits were investigated. Respiratory gas was sampled at four different sites in the respiratory tubing system. Analysis of volatile components was based upon adsorption onto activated charcoal, desorption by means of microwave energy, gas chromatographic separation and flame ionisation or mass spectrometric detection. Isoflurane concentrations in the blank respiratory circuits, in the control group, and in the inspiratory limb of patients with …preceding isoflurane inhalation were at the limit of detection (<10−12 mol/l). In the isoflurane group, isoflurane concentrations in the inspiratory and expiratory limb differed considerably. Using the method described, substances at very low concentrations could be identified as originating in the patient or as coming from the gas delivery system. Show more

Keywords: Breath analysis, isoflurane, mechanical ventilation

DOI: 10.3233/THC-1999-7102

Citation: Technology and Health Care, vol. 7, no. 1, pp. 29-37, 1999

Authors: Papaioannou, G. | Naniopoulos, A. | Bekiaris, E. | Spaepen, A.

Article Type: Research Article

Abstract: This paper presents the methodological framework for the development of an innovative wheelchair able to solve the problem of use within all transportation modes (car, bus, train, ship, aeroplane). This task calls for a multi-step integrated methodology in order to gather and reconciliate conflicting user needs and requirements regarding safety, manoeuvrability and comfort. The paper describes also the methodology adopted for the system architecture of a modular design wheelchair as well as for its evaluation, ranging from crash tests (both simulations and real tests) to vibration and comfort studies. The work stems from the research conducted in the TRANSWHEEL project …(DE 3013), partly financed by the European Union’s DE/TAP programme. Show more

DOI: 10.3233/THC-1999-7103

Citation: Technology and Health Care, vol. 7, no. 1, pp. 39-51, 1999

Authors: Cavouras, D. | Kandarakis, I. | Prassopoulos, P. | Kanellopoulos, E. | Nomicos, C.D. | Panayiotakis, G.S.

Article Type: Research Article

Abstract: Phosphor materials used in X-ray image receptors were evaluated by the effective performance index (EPI). EPI describes the dependence of image quality on X-ray to light energy conversion and light diffusion processes. EPI was experimentally determined by means of X-ray luminescence (XLE) and MTF measurements performed on Y2 O2 S:Eu, Y2 O3 :Eu, and YVO4 :Eu phosphors. The spectral compatibility of these materials with optical detectors (films, photocathodes, photodiodes) was also determined. Highest EPI values were obtained for Y2 O2 S:Eu-GaAs combination at mammographic energies. All phosphors could be of use in digital X-ray imaging being adequately compatible to silicon …photodiodes employed in digital detectors. Show more

Keywords: Phosphors, X-ray image detectors, X-ray luminescence, MTF

DOI: 10.3233/THC-1999-7104

Citation: Technology and Health Care, vol. 7, no. 1, pp. 53-61, 1999

Authors: Keel, Matthias | Wolf, Martin | Baenziger, Oskar | Dietz, Vera | von Siebenthal, Kurt | Bucher, Hans U.

Article Type: Research Article

Abstract: Near infrared spectrophotometry has been used to measure total cerebral hemoglobin concentration (μmol/l) as a major indicator of the oxygen transport capacity in neonates. The aim of this study was to find out how the position of the probe influences the quality of the measurement and the actual cerebral hemoglobin concentration-values. We studied 10 healthy preterm infants with a mean gestational age of 31.5 weeks and a birthweight of 1513 g. The data were collected by a two channel near infrared spectrophotometry system using a geometrical principle to measure absolute cerebral hemoglobin concentration. The incoming signal of the light …emitting diode as a value allows a prediction of the quality of the measurement: a high value refers to a high signal/noise ratio. Starting from the centre of the forehead (0%) for each measurement the probe was moved by 2.5% of the headcircumference to the left respectively right side of the head up to 20%. The cerebral hemoglobin concentration-values increased from 87 respectively 93μmol/l up to 164 respectively 173μmol/l on the right respectively left side, while the light emitting diode signal-values decreased from 21 respectively 21 down to 10 respectively 11, the more laterally the probe was moved. There were two plateaus of these variables in the frontal (0–5%) respectively lateral (15–20%) region. A further investigation on a solid phantom for premature heads showed that hair has either no or a contrary effect on the cerebral hemoglobin concentration-values than expected. The extracerebral tissue (soft tissue, skull, cerebrospinal fluid layer) is discussed to have a significant influence on the light attenuation in adult heads. Still there is no evidence for a significant effect on prematures, because this overlying tissue is much thinner and more translucent than the one in adults. Absolute cerebral hemoglobin concentration measured by near infrared spectrophotometry is substantially influenced by the position of the probe at the infant’s head. Considering our results we recommend placing the probe at 2.5% of the headcircumference away from the centre of the forehead for the measurement of cerebral hemoglobin concentration in premature infants. Show more

Keywords: Cerebral hemoglobin concentration, near infrared spectrophotometry, preterm, infants, positioning, probe

DOI: 10.3233/THC-1999-7105

Citation: Technology and Health Care, vol. 7, no. 1, pp. 63-73, 1999

Authors: von Orelli, A. | Lehareinger, Y. | Rol, P. | Niederer, P. | Doswald, D. | Felber, N.

Article Type: Research Article

Abstract: Endoscopes are key elements in the application of minimally invasive medical procedures. Thereby, image quality, ease of application and safety are of decisive importance for the user. This communication is primarily concerned with aspects relating to image quality. Standard television technology is presently used in endoscopes for image presentation purposes. It is however shown, that the inherent optical quality of most endoscopes exceeds the performance of standard TV. Accordingly, a special purpose advanced digital television system exhibiting true colour performance has been developed. Since endoscopic images usually are circular, its aspect ratio is quadratic with a spatial resolution of 1000 …× 1000 pixels. It has furthermore a temporal resolution of 1 to 30 Hz noninterlaced and a contrast resolution of 56.6 dB. The design and performance of the system is documented. Show more

DOI: 10.3233/THC-1999-7106

Citation: Technology and Health Care, vol. 7, no. 1, pp. 75-84, 1999