Percutaneous laser Doppler flowmetry (LDF) and bipolar surface electromyography (EMG) were used simultaneously for measurement of skeletal muscle (trapezius) perfusion in relation to static load and fatigue. On-line computer (386 SX) processing of the LDF- and EMG- signals made possible interpretation of the relationship between the perfusion and the activity of the muscle. The single fiber laser Doppler technique was used in order to minimize the trauma. A ray-tracing program was developed in the C language by which the optical properties of the fiber and fiber ends could be simulated. Isoirradiance graphs were calculated for three fiber end types and the radiance characteristics were measured for each fiber end. The three types of fiber-tips were evaluated and compared in flow model measurements.

A novel spectrophotometer as based on the deflection of a secondary element for measuring clear and highly turbid materials within the millisecond time range has been developed. The number of optical components of the monochromator is reduced to the absolute minimum. This results in excellent light-throughput and a low stray-light level. The spectrophotometer has been designed allowing spectral measurements of absorption, transmission, reflection and luminescence in a single beam mode as documented by various examples. Its design is highly flexible and the price/quality relation might be adopted to the envisaged purpose. An appropriate computer-program providing data acquisition, control functions as well as numerous analytical capabilities has been developed on the basis of the compiler language power basic; indispensably `fast routines' are written in assembler language.

A miniature optical sensor based on the fluorescent indicator, 8-hydroxyl-1,3,6-pyrene trisulfonic Acid Trisodium Salt (HOPSA), was developed for physiological pH measurement. Dowex-1 strongly basic anion exchange resin was used as a medium to immobilize the indicator on the end of an optical fiber to form a pH sensing layer. Polyetherurethane was dip- coated onto the sensing layer as the permeable membrane for H⁺. The properties of the sensor were assessed and found to be suitable for monitoring physiological pH values.

Near infrared spectroscopy (NIRS) is a relatively new method which is suitable for monitoring oxygenation in blood and tissue in the brain of the fetus and the neonate. The technique involves in-vivo determination of the absorption of light in the wavelength range 775 to 900 nm through such tissue and converting such changes in absorbance to provide information about the changes in the concentration of oxygenated and de-oxygenated haemoglobin (HbO₂ and Hb). Recent developments of the methodology now enable the calculation of changes in cerebral blood volume (CBV) as well as absolute CBV and cerebral blood flow (CBF). The attraction of this method is its applicability to monitor cerebral function in a wide variety of patient groups. Although primarily developed for neonatal use it is today applied on the fetus to investigate fetal hypoxia and on adults undergoing surgery.

An optical fiber sensor for gastric pH detection is described, making use of plastic fibers as light carriers and a proper electronic system for both source driving and signal processing. The use of a suitable microprocessor and an internal buffer allows the realization of a portable and reliable device, fed by batteries. The indicators, bromophenol blue (BPB) or thymol blue (TB), are immobilized on controlled pore glass (CPG) fixed at the end of plastic optical fibers following a proprietary process. The realized optrode, satisfying clinical requirements, was tested `in vitro.' A precision of <EQ 0.04 pH units and a response time of (<EQ 15 seconds) were reached.

The main scheme of the cell for measuring as well as itself sensor device, the analyses condition and the results of quantitative determination of several antigens such as estradiol-17, chorionic gonadotropin, antibodies to influenza virus, total IgG, and cell of Salmonella Typhimurium are presented. Special attention is paid to immobilization of one of the immunocomponents on the fiber optic surface.

The new dye which has improved spectral characteristics synthesized on the basis of platinum complex of the porphyrin-like compound was studied with the view of its application to oxygen sensing. It resulted in a new solid-state oxygen-sensitive material with advanced working characteristics which is highly compatible with excitation with yellow LEDs. This new sensing material makes it possible to develop simple fiber-optoelectronic devices -- prototype oxygen sensors. One of the embodiments was constructed which utilizes powerful yellow LED as a light source, silicone photodiode as a photodetector, and has a fiber-optic output terminated with an active element (oxygen membrane). The electronic scheme of the device provides modulation of LED at a kilohertz range frequency and is capable of measuring specific luminescent signal. The system is now under improvement and optimization with emphasis to lifetime measurements performed by phase method.

Optical sensors often suffer from poor long-term stability. This drawback can be overcome by using fluorescence decay-time measurement as the sensing principle. In this way calibration- free chemical sensors can be developed. The sensing scheme has been used so far mainly in connection with dynamic quenching, for example in oxygen sensors. We have succeeded in extending it to ground-state indicator-analyte reactions, thus obtaining stable optical sensors for decay-time sensing of various analytes.

The procedure of imaging in flow, evoked by the need for simplified and reliable particle identification in aquatic science, means taking cell images directly from the transducer of a flow cytometer. From that point of view imaging in flow is the link of the traditional microscopical method and the modern flow cytometric technique for analyzing particles. Principal problems rising from that approach are discussed in this paper. This encloses positioning of the objects to be imaged, design criteria for illumination and imaging optics, the procedure for taking asynchronous video images and requirements concerning the light source.

A new CCD sensor featuring 1024 X 256 pixels of 19 micrometers X 19 micrometers has been developed to address both high end and low cost spectroscopy applications (fluorescence, Raman, pulsed laser, emission and absorption). Specific technology and design have been used to optimize capabilities of the sensor (binning, user selectable operating conditions, ...) and to maximize performances (noise, dynamics, linearity, response uniformity, dark signal,...). This makes it an excellent candidate for all medical, biomedical, biochemical and biological spectroscopy applications.

The aim of this paper is to introduce an optoelectronic mammoscope that has been developed at Warsaw University of Technology for early breast cancer detection. The idea of the mammoscope is based on a direct comparison of light transmission spectra through breast tissue obtained for two selected wavelengths: 670 nm and 810 nm. As light sources, two types of laser diode are used. The optoelectronic mammoscope is equipped with a specially designed optoelectronic head which decreases light path throughout the breast tissue under examination and, simultaneously increases intensity of the light transmitted through the tissue. At the output, a CCD camera coupled to the IBM PC/486 computer is used for detection of shadow images created by the transmitted light at both wavelengths.

In this paper an overview on the activity developed at IROE in the field of optical fiber sensor for medical applications is given. Bile sensor for monitoring the entero-gastric reflux, pH sensors for the detection of blood and gastric acidity and oxygen sensor, also suitable for the measurement of biological compounds via enzyme reactions, are described. Before the realization of each sensor, a thorough spectrophotometric investigation was undertaken: it has been considered fundamental in the design and planning of the optical fiber chemical sensor, since it allows us to obtain a better understanding of the behavior of the chromophores, immobilized or not, which act as optical transducer in the optrode and therefore, to optimize the optrode from an optical point of view. Moreover, if the final goal of the sensor was the utilization for in vivo measurements, particular attention was paid to the biocompatibility of the optrode.

Temperature monitoring of tissue (in vitro) and human skin (in vivo) during Ar-laser irradiation with the help of a radiometric temperature sensor based on IR silver halide optical fibers is presented. Fiber optic radiometry makes possible accurate temperature measurement and does not require contact with the heated biological object. Using a IR silver halide fiberoptic radiometric thermometer we obtained accurate temperature rise-decay dependencies of the heated biological object and demonstrated the non-uniform temperature distributions in them.

Measurements of calcium ion activities with lately available Schott glass `LaSF35' as the multiple internal reflection element are presented. Use of the evanescent wave in absorption mode as well as corresponding data for the refractive index are shown. Looking from the backside at the membrane eliminates optical sample interferences and the crucial assumption of a homogeneous bulk optode can be verified by profiling into a controlled depth of the membrane.

The aim of the paper is to present an idea of a low-cost optical fiber colorimetric pH sensor (with disposable probe). Most of colorimetric sensors consist of two fibers: the illuminating one and one for collecting reflected light. Only one optical fiber is used as a sensing probe in our pH sensor. The end of the fiber is covered by a pH-sensing membrane, which is made of polyvinyl chloride. The colorimetric indicator (bromothymol blue) was immobilized on an ion- exchange resin. The sensing fiber is connected with two optical fiber couplers (type Y). The first coupler guides analytical and reference wavelengths from the light emitting diodes (LED) and the second one transmits light to the photodetector. Only one photodetector is used. Optical signals are filtered electronically because the LEDs are modulated at different frequencies. The results of the measuring tests of the sensor are presented.

The synergy of novel MIR-fibers with Fourier Transform Infrared (FTIR) spectroscopy opens new horizons in applications of spectroscopy in the 4 - 16 micrometers range for in line control of chemical processes, in vivo medical diagnostics and in situ pollution monitoring. The innovated bare core and core-clad MIR-fibers are produced by hot extrusion method from the crystals of silver halides solid solutions. These non toxic and non hygroscopic fibers are characterized by low optical losses - 0.1 - 0.5 dB/m nearby 10 micrometers , and high flexibility -- R_bending > 10 - 100 fiber diameters. Some prototypes of accessories for FTIR spectrometers, based on commercially available MIR-fibers for several areas of promising applications are developed. Non-invasive medical diagnostics in vivo including cancer diagnostics are possible. FTS methods with evanescent fiber probes for cancer detection in human organs is exemplified in this paper and their great potential is demonstrated.

In the present paper a miniaturized ion mobility spectrometer is presented which consists of a miniature ionization detector in combination with a simple ion drift arrangement. By means of this low cost system it is possible to determine a large number of organic compounds. The system is suitable for process control and monitoring of air pollution.