Fabrication process and transmission properties of nontoxic and durable ZnS-coated silver waveguides have been described. By suitably choosing the thickness of ZnS layer, hollow waveguides have been realized to transmit Er:YAG, CO, and CO₂ laser light simultaneously or independently with low-losses. A glass-based mandrel is employed in the fabrication process to improve an output beam quality from the waveguide.

Nd:YAG lasers have become fundamental tools in the medical field, because of the low absorption and high scattering in tissue at the emission wavelength of 1.06 micrometers . Therefore the development of new laser delivery systems is a very attractive goal. In this paper a complete fiber-optic delivery system is described. Such a system is composed by a laser-to- fiber and a fiber-to-fiber coupling device, in which GRIN rod lenses are utilized. Furthermore a distal handpiece, suitable for medical applications, has been properly designed and manufactured.

Flexible plastic waveguides (WG) were devised for the delivery of Er-YAG laser energy in curved trajectories. The WG were optically characterized. The WG transmitted energy could drill a hole in teeth enamel hence it can be used as a substitute for a pneumatic drill.

Fluorocarbon-polymer coated hollow waveguides have been proposed for the first time for infrared light transmissions in the fields of medicine and infrared measurements. The fluorocarbon-polymer has many advantages over other dielectrics such as non-toxicity, durability, and low-loss property. Two types of coating methods have been employed to fabricate the waveguides and loss spectra of the waveguides have been measured. It is shown that fluorocarbon-polymer coated hollow waveguides have low loss characteristics.

Laser-induced breakdown (LIB) thresholds in AgCl_xBr_1-x crystals and fibers were studied under CO₂ pulse and cw laser excitation. The dependence of the LIB and IR absorption on composition and temperature treatment suggests, that the LIB in silver halide crystals and fibers is due to the absorption at 10.6 micrometers caused by cation vacancies bound with charged dislocation silver halides. The lower optical stability of the fibers is due to defects induced by the heating under pressure, applied during the production of the fibers by extrusion and the subsequent fast quenching to RT. A simple method for reduction of the IR absorption is proposed.

The laser scalpel with ellipsoidal, parabolic, conical and truncated conical tips, and laser scalpels without exiting optics system have been studied. The problems of laser radiation propagation and distribution of temperature field in the tips are considered. The radiation transfer equation is solved for axial symmetric semi-transparent bodies by methods of statistical modeling with linear optics approximation in unscattering medium. The distribution of radiation intensity is obtained at the tip exits by statistical analysis. It is shown that the main thermal source is the absorption of laser radiation on the surface of the tip. The energy equation is solved for real instruments by finite-difference methods, taking into account the nonlinear transport coefficients.

The effect of transmitted CO₂ laser energy ((lambda) equals 10.61 micrometers ) upon heating of a plastic hollow waveguide (PHWG) was investigated. The temperature rise of the external tubes wall was recorded by thermocouples or thermal imaging system. The most affected regions of the waveguide were the curved segments and the distal end. Gas cooling and external metal layer reduce this undesired effect.

This paper details several experiments which measure the power distribution at the outlet of the FPHW under straight and bent trajectories.

Anthropos III is an elastic volume model, which is adapted to animate the correlation of motion complexities. This 3D ergonomic system is a module of the CAD software CADKEY. The program animates a man-model, it can be varied of all ages and sizes, consists of 90 body elements and joints as modules. The system is able to calculate the real body motions according to biomechanically correct motion phases in a local coordinate system, by `machine- joints.'

The quality of an image transmitted by a multicore, multimode fiber bundle has been investigated. The influence of the limiting factors such as the spatial sampling of the bundle, the cross-talk between each core and the radiative modes in the intercore space has been determined. Two different methods to determine the MTF are compared. The analysis of the data obtained experimentally for the coupling coefficients between fiber cores suggest that two different mechanisms must be invoked to explain the degradation of the image transmitted through the fiber bundle: the cross-talk and the leaky modes.

An optical transcutaneous power converter has been developed for the power supply of implanted devices. It consists of a light source, optical fiber system and a photo detector. The light source is either a halogen lamp or continuous high-power laser diode which illuminated skin surface. The light penetrates through the skin to the solar cells. The preliminary experiments with a slice of tissue in between the light source and the solar cells showed that the power transfer efficiency was 40% in comparison to direct illumination of the solar cells. The maximum electric power obtained with a slice of tissue simulating the skin was about 8 mW at a laser diode run at a power of 100 mW. The electric power transferred is enough to supply low power consuming CMOS circuits.

Optimization of a ring optical-fiber catheter for oncological diagnostics has been carried out. A new method of cancer diagnostics using autofluorescence of tissues has been realized during endoscopy and surgery, using a specially developed optical scheme and catheter for oncological diagnostics. Criteria of stomach and lungs cancer diagnostics obtained by analysis of autofluorescence differences on more than 10,000 spectra measured in vivo from human tissues are presented.

In this paper several types of fibers for power delivery of excimer, He-Ne, argon, Nd:YAG, Ho:YAG, Er:YAG laser energies are described. The attention is focused on quartz fibers and infrared fibers from As₂S₃ and As₂Se₃ glasses.

The wavelength of CO laser radiation has many advantages and extends application in medicine (laser surgery, laser angioplasty), industry (material processing), etc. For power delivery of CO laser chalcogenide glass fibers (As₂S₃, As₂Se₃, As₂S_xSe_3-x) seem to be the best transmission medium.

Lasers have found increasingly wide applications in biomedicine, and, in particular, for diagnostic purposes. Indeed, the properties of laser radiation (high spatial and temporal coherence) and the consequent possibility of defining the physical parameters of radiation- matter interaction with great accuracy, make an extremely precise and selective action possible. This paper gives a survey of the most recent approaches to laser-based diagnosis in basic and applied biomedical research, together with a discussion of the potentials of diagnostic laser systems for use in the clinical practice.

This paper describes an improvement in the image system for near infrared videoangiography as compared with a previous intensified TV camera incorporated in a standard fundus camera. The new system uses a cooled CCD camera with 1152 X 770 elements. Because of a very low readout noise and variable time integration, this camera was used at very low light. This avoided the potential hazard to the eye resulting from over exposure and increased the patient's physical comfort during ophthalmic imaging. This paper reports the results of the first phase of the work in which several sequences of ocular fundus images were analyzed.

A laser Doppler perfusion imager has been developed that makes possible mapping of tissue blood flow over surfaces with extensions up to about 12 cm X 12 cm. The He-Ne laser beam scans the tissue under study throughout 4096 measurement sites. A fraction of the backscattered and Doppler broadened light is detected by a photo diode positioned about 20 cm above the tissue surface. After processing, a signal that scales linearly with perfusion is stored in a computer and a color coded image of the spatial tissue perfusion is shown on a monitor. A full format scan is completed in about 4.5 minutes. Algorithms for calculating perfusion profiles and averages as well as substraction of one image from another, form an integral part of the system data analysis software. The perfusion images can also be exported to other software packages for further processing and analysis.

A device for the recording of the photoplethysmographic (PPG) signal, which filters the dc value without distorting the pulse shape, was developed. PPG measurements were performed on the finger of the left hand while the right hand exerted a static muscle stress. The amplitude and the period of the PPG signal decreased when the other hand was raised to above heart level, and when it exerted a handgrip stress. These effects are associated with increased activity of the sympathetic nervous system.

The clinical application of a laser-Doppler-vibrometry for recording the motion of the tympanic membrane is relying on the harmlessness of the used He-Ne-laser beam. Even when the daily experience tells that an intensity of 1 mW focused onto the skin introduces no obvious thermal effects, focusing this beam down to a waist of a diameter of 40 micrometers , as it is done in this case, raises up the density of power to 80 W/cm². Safety rules postulate a maximum radiation time at this density of less than 10 ms sec, which is much too short to perform any measurement. Therefore the threshold and the degree of thermal effects have been investigated histomorphologically.

Invasive intra-arterial blood pressure measurement is the most accurate method but not practical if the subject is in motion. The apparatus developed by Wesseling et al., based on a volume-clamp method of Penaz (Finapres), is able to monitor continuous finger arterial pressure waveforms noninvasively. The limitation of Finapres is the difficulty in measuring the pressure of a subject during work that involves finger or arm action. Because the Finapres detector is attached to subject's finger, the measurements are affected by inertia of blood and hydrostatic effect cause by arm or finger motion. To overcome this problem, the authors made a detector that is attached to subject's ear and developed and optoelectronic monitoring systems for ear arterial pressure waveform (Earpres). An IR LEDs, photodiode, and air cuff comprised the detector. The detector was attached to a subject's ear, and the space adjusted between the air cuff and the rubber plate on which the LED and photodiode were positioned. To evaluate the accuracy of Earpres, the following tests were conducted with participation of 10 healthy male volunteers. The subjects rested for about five minutes, then performed standing and squatting exercises to provide wide ranges of systolic and diastolic arterial pressure. Intra- and inter-individual standard errors were calculated according to the method of van Egmond et al. As a result, average, the averages of intra-individual standard errors for earpres appeared small (3.7 and 2.7 mmHg for systolic and diastolic pressure respectively). The inter-individual standard errors for Earpres were about the same was Finapres for both systolic and diastolic pressure. The results showed the ear monitor was reliable in measuring arterial blood pressure waveforms and might be applicable to various fields such as sports medicine and ergonomics.

A newly developed optoelectronic monitoring systems for ear arterial pressure waveform (Earpres) was tested in ergonomics and sports science. Changes in systolic and diastolic blood pressures and heart rate were continuously measured by the system during VDT operations such as word processing and computer games, and during two different styles of weight lifting, one-hand and two-hands curls, with three different weights respectively. Statistical analysis of the results showed that systolic and diastolic blood pressures and heart rate increased during VDT operation, and in the extreme case the increments of those were as high as 78 mmHg and 50mmHg respectively during computer game operation and 50 bpm during word processor operation. It was also statistically clarified that systolic and diastolic blood pressures and heart rate increased in accordance with weight during one-hand and two-hands curls. It was ascertained that the results obtained by Earpres agreed for the most part with physiological knowledge; some results might be new findings. Earpres was thus validated as a physiologically and ergonomically useful apparatus. Additionally, an apparatus was constructed to detect the exact location of an artery in the ear, composed of a halogen lamp, a band-pass filter, a bundle of optical fibers, and a CCD device. With the apparatus, Earpres became much easier to handle.

The mucosa of the edentulous ridges and the hard palate is used to bear denture bases. While the etiology of mucosal disorders caused by material and microbiological factors is well known, the effects of mechanical stress on denture bearing mucosa are comparatively unexplored. To learn more about reactions of compensation against mechanical stress of the denture bearing mucosa we studied physiology of the tissues covering the alveolar ridge and the hard palate. We took non-invasive measurements of the concentration and oxygenation of hemoglobin in several places of the mucosa by using a micro-lightguide spectrophotometer (EMPHO). On this occasion the magnitude and duration of the force, the frequency of the loading and the interval of rest have been varied. The result was that the concentration of hemoglobin decreased significantly inside the mucosa when the denture bearing mucosa was stressed already by a slight but constant compression load. However, a total ischemia was not seen even in great mechanical loads. After the stress ended a reactive hyperemia took place spontaneously.

There is enormous potential for application of lightguide tissue reflectance spectrophotometry in the diagnosis and treatment of peripheral vascular disease. In the present study, measurements were carried out in 10 such pre-amputation patients to compare the use of micro-lightguide spectrophotometry with the macro-lightguide technique. These preliminary results show excellent agreement between the new, non-invasive micro-lightguide technique and the `gold standard' skin blood flow measurements. This technique could thus provide a more functional, non-invasive assessment of healing potential than skin blood flow measurement.

The temperature of uncovered skin does not provide useful information about the blood temperature and blood flow. The information obtained from the same measurement for thermally insulated skin is more significant. In order to measure the temperature of thermally insulated skin, a teflon cylinder, covered by polyethylene layers, was applied on the skin of the hand. The polyethylene layers permit partial transmission of the infrared radiation through it. Preliminary results show that underskin temperature can be obtained from measurements of radiation transmitted through the thermal insulation which was applied to the skin, and that underskin temperature is related to tissue blood flow more than uncovered skin temperature.

Transcutaneous bilirubinometry based on reflectance spectroscopy technique requires the modelling of bilirubin photochemistry and metabolism in skin, and the solution of inverse problems to derive pigment concentrations from spectral measurements. The influence of bilirubin photochemistry occurring during the initial stage of phototherapy on the reflectance spectrum of an icteric tissue is analyzed using a 5-layer skin model, and an algorithm is presented to evaluate bilirubin concentration during phototherapy. An in vivo reflectance spectrum during phototherapy is presented where the configurational, reversible photoisomerization of bilirubin is observed for the first time.

This paper describes two new spectroscopic techniques which are utilizing hybrid integrated optoelectronics particularly suitable for field and hand-held use. First, the LED module is based on a linear array of light emitting diodes and a fixed monochromator, and provides a solid-state electrically scanned source for pre-dispersive spectrometers. A prototype module operating from 810 to 1060 nm with resolution of 10 nm scans one spectrum in 19 ms and has a solid glass construction with dimensions of 4 X 4 X 7 cm. Potential applications include miniature, rugged and low cost instruments for transcutaneous blood and tissue spectroscopy in the near infrared (NIR) region.

Main physical phenomena, exploited for the realization of optical chemical sensors, and different immobilization techniques for the realization of the optrode are reviewed and general considerations on the optoelectronic system are given. Many interesting examples of constructed optrodes are described.

Optoelectronic instrumentation finds increasing applications in the clinical-laboratory work and in biological research. Radioimmunological tests start being substituted by methods which quantify immunoreactions by means of non-hazardous optical techniques. The main ideas involved in the design of such optical instruments, like photometers for enzyme immunoassay or precise fluorometers for fluoroimmunology, are briefly described. Emphasis is then given to a new development in optical detectors for liquid chromatography, that is a very sensitive dynamic-laser-light-scattering system which measures the hydrodynamic radius of the eluting macromolecules directly after the column. Calibrations or knowledge of ancillary parameters, like the refractive-index increment and concentration, are not required.

A combination of conventional-size liquid chromatography and visible diode-laser induced fluorescence (DIO-LIF) detection has been developed and applied for the detection of a model photosensitizer, AlPcS₂, in biological samples. Conventional fluorimetry was found to give unsatisfactory information. A detection limit of 2.1 X 10^-12 M (S/N equals 3) was obtained for AlPcS₂ in both rat urine and faeces extracts using the DIO-LIF system, 20-fold lower than obtained with a conventional fluorescence detection system, when used in combination with chromatography.

Three main methods are proposed for the biomonitoring of chemicals in water medium: laser spectrofluorometry, which is based on the excitation and recording of the spectra of fluorescence; laser scattering, which is connected with measurement of the Doppler shifts of the scattered light from the motile cells; videomicrography, which provides the analysis of parameters of photomovement of motile cells via microscope and video system. Such chemicals as surface-active substances, heavy metals and pesticides were determined in water medium due to these methods.

Scanning Probe Microscopies, particularly AFM (Atomic Force Microscopy), appear to be very useful tools for visualizing biological structures. Their exceptional features are: resolution down to atomic scale, non invasive method, no manipulation of the sample, physiological conditions of operation. But many problems remain to be solved for routine applications in the biomedical field. Here these problems are treated and suitable optical methods for making more reliable the application of Scanning Probe Microscopy to biological preparations are illustrated and discussed.

Long pulse excimer laser radiation can be efficiently coupled and transmitted through optical fibers allowing the achievement of both photoablative and photomechanical effects. In this work the investigation has been focussed on the urologic surgery field to demonstrate the effectiveness of an excimer laser system for very different therapeutic tasks: recanalization of urethral stenosis and lithotripsy. The choice of the suitable radiation dosimetry and the technical solutions employed provide to the surgeon a multipurpose laser system with a wide range of utility in comparison with other laser systems.

Progress in the use of miniature optoelectronic systems based on Coherent-Light-Emitting- Diodes (CLEDs) and CLED-pumped solid-state lasers (Microlasers) is reported for: (1) retina photocoagulation with 800 nm diode lasers and 532 nm Nd:YAB Microlasers; (2) endoscopic photocoagulation of gastrointestinal tumors with an 800 nm high power multi-CLED system; (3) 800 nm diode laser-assisted microvascular anastomosis; (4) photodynamic therapy of tumors with 780 nm CLED and 660 nm LED.

The effect on living tissues of different pulsed solid state lasers: Nd:YAG ((lambda) equals 1.06 micrometers ) Er:glass (1.54 micrometers ), Ho:YAG (2.1 micrometers ) and Er:YAG (2.94 micrometers ) is compared with the continuous wave Nd:YAG- and CO₂-lasers used in operating theaters. Portable Er:glass- and Er:YAG-lasers are developed for surgery/cosmetics and HIV-safe blood testing.

This paper deals with the improvement of the characteristics of the CO₂ lasers used in surgical systems, particularly the design of single mode laser tubes with high output power density per unit length, the active control and monitoring of laser power level and its stability during long periods, the precise control of the irradiation time when the exposure regimes are diversified and the safety measures against uncontrolled irradiation, as well as the design of new beam delivery systems and specialized interfaces between the laser surgical units and the operating theatre.

The high power laser beam caused typical `V' form defects in living tissues directed at an incidence of 90 degree(s). In other cases the defects are elliptic. The authors constructed a laser endoscope with a fixed and revolving mirror. Using this device they could not only direct the laser beam to the areas of the oral cavity that are accessible with difficulty but they could also achieve a laser beam incidence always close to 90 degree(s).

A real time monitoring of the fiber delivery system is investigated, based on the detection of the backscattering variations due to a damage of the fiber distal end. The modal backscattering distributions from flat, bulb and damaged tips in air and in water were studied utilizing a fiber-fiber directional coupler. The results seem to be encouraging in view of practical applications.

Radiological procedures to destroy deep neoplastic laesions of internal organs - without surgical exploration is a highly instnimentation dependent technique, reducing the risk for patients and the costs of hospitalisation. Nonturnor therapeutic radiology can be used for chernolysis: syrnpathectomy, discectorny, but there is a danger of complications because of uncontrolable fluid distribu— tion, wich can produce unexpected necrosis. Laser, guided by radiologiacal imaging methods, gives the possibility of precise intervention /nucleus pulposus denaturalisation or brain tumor fiber optic destruction, as introduced by Ascher/. Laser — intersti— tial — hypertherrnia is a new method /developed by Bown/ to increase the tumor destruction, and it promotes the effect of other anti— tumo r therapies, as radiotherapy, cytostatic therapy or photodynainic therapy. Photodynarnic therapy by systemic administration causes a skin photosensitivity for 30 — 40 days, and the hernatoporphyrin concentration in the tumor tissue is only 1 — 2 ,ug/g. Ideal application for deep tumor effective laser desstruction was developed by Gatenby: CT — guided fiberoptic direct injection of HpD prepared PDT. The direct HpD injection into the tumor reults 50 — 100 ,ug/g concentration of the photosensitiser in the tumor tissue, without systemic effects, as skin photosensitivity. That's, why the exposure can be repeated at weekly intervals. Under 2 cm size the results are excellent, but even larger masses, have had not respomided to conventional therapy showed significant improvement in size and in pain aswell. The procedure can be on outpatient basis

Progress in phototherapeutic systems for neonatal hyperbilirubinemia based on better understanding of bilirubin photochemistry and metabolism, improved optical models of skin, and new fiberoptic delivery systems is reported. The very efficient use of a new blue-green phototherapy fluorescent lamp is reported for the first time.

Information on optical activity of biological substances under test is often influenced by other ingredients with optical activity or fenomena interfering with the process of polarization rotation. The influence of cell-medium interface can be excluded by solving the two-equation system, following from two independent measurements of optical activity of the same biological substance in two identical cells of different lengths. In a similar way, the system of n equations can be found by excluding the interfering components, supposing their frequency- dispersion or temperature dependences are known from previously made experiments. Our measuring system uses polarization modulation (linear rotation by Faraday modulator). For 10% depolarization in solutions, we achieved an accuracy of 15 arc. sec at 2 mW laser power and simple film analyzers are enough for such results. A microprocessor simplifies the routine calculations.

The spectral characteristics of hairs of animals, particularly the parameters of fluorescence, have been considered as genotypic indexes of animal diversity.

This paper presents recent results on a combined optical and acoustical system for a new endoscopic controlled laser and ultrasound surgical therapy (LUST). The goal is the combined employment of the cavitation ultrasonic surgical aspiration (CUSA) and the laser in endoscopic surgery. With such a system the CUSA technique can be used for selective tissue cutting and the laser for blood coagulation, vaporization, general tissue cutting (all this with cw lasers) and photoablation (with pulsed lasers). The transmission of acoustical energy via optical fibers is theoretically calculated. First experimental results on the transmission of high power ultrasound (US) via a silica fiber are shown. Furthermore future biomedical applications including angioplasty and endoscopic surgery are discussed.