An opto-electronic projection moire apparatus was developed for in-vitro studies of the eardrum. Moire topograms are generated by real-time video image subtraction, yielding 25 new interferograms per second. By using different reference images, both shape and deformation fringes can be obtained, without manipulating the object or the setup. Calibration measurements show a measuring precision of 5 micrometers . The setup is used to measure the shape and deformation of the eardrum. Parameters such as, for instance, the volume displacement of the pars flaccida, can be calculated from computer evaluations of the topograms.

A new optical tissue phantom is presented, which consists of a polymer film containing scatterers and absorbers. With this tissue phantom, tissue models can be constructed having the optical properties and layered structure similar to those in living tissue. Optical properties can be specified for each layer, with a resolution of 20 micrometers . With this tissue phantom, a new laser Doppler testing principle is developed using a repetitive construction of static and moving layers. Monte Carlo simulations show that the requirements to the optical matching quality provided by the medium between the layers are not very restrictive. Two applications of the new tester are shown. For a single laser Doppler blood flow monitor, the depth sensitivity characteristics of two fiber optic probes are measured. Furthermore, an attempt is made to compare the outputs of two different laser Doppler instruments measuring on the same tissue phantom, with the same flow situation. Such a comparison may be important when new instruments are used for a specific medical application.

We describe here anew 3D numerical holographic method which allows intensity and phase contrast imaging. This technique involves a CCD camera as recording device and a numerical method for the reconstruction. We demonstrate here that, in spite of their low resolution, the recording capacities of standard CCD cameras are large enough for the holographic imaging of a few millimeter size objects. 9

Using a polarization sensitive Michelson interferometer, we measure 2D images of optical birefringence in bovine tendon as a function of depth with a technique known as optical coherence tomography (OCT). Detection of the polarization state of the signal, formed by interference of backscattered light from the sample and a mirror in the reference arm, gives the optical phase delay between light that has propagated along the fast and slow axes of the birefringent tendon. Images showing the change in birefringence in response to laser irradiation are presented. The technique allows rapid non-contact investigation of tissue structural properties through 2D imaging of birefringence.

The 'spectral radar' is an optical sensor for the acquisition of skin morphology. The scattering amplitude a(z) along one vertical axis from the surface into the bulk can be measured within one exposure. No reference arm scanning is necessary. We discus the theory of the sensor, including the dynamical range and we show in vivo measurements of human skin by a fiber optical implementation of the sensor.

Optical coherence profilometry (OCP) may be a useful tool for medical diagnosis of human skin. Different medical indications show distinct alterations of the skin surface. We measure the 3D shape of the surface of the skin by the use of the 'coherence radar', which is based on short- coherence-interferometry. The measuring uncertainty is less than 3 micrometers . The measuring time takes about 4 seconds. We perform in vivo 3D skin mapping of naked skin without preparation. We describe methods to compensate for the movement of the patient during the measurement. In order to realize the sensor for clinical application a fiber optical implementation is introduced.

Optical spectroscopy techniques are frequently used to non- invasively monitor various physiological functions such as tissue and blood oxygenation. It is desirable to develop a methods to localize these measurements and quantify the parameters of interest, e.g. oxygen saturation. An optical tomography system for imaging the oxygenation of the limb is presented. Initially, a rotate-translate optical imaging system was developed. Image reconstruction was performed using a conventional filtered back projection scheme. With this system the limits of spatial and contrast resolution as a function of the absorption and reduced scattering coefficients were investigated. The limiting factor was found to be contrast resolution. A second generation imaging system, using a rotate-rotate type scanning system, has been constructed. Data obtained with this system utilizes all the light emerging in the plane of measurement, and does not assume rectilinear propagation. The image reconstruction algorithm developed for this uses diffusion theory to model the light transport, and an iterative reconstruction algorithm. Results obtained with this model are presented. A further method to improve image quality is the use of a phase resolved technique, which uses amplitude modulation of the light source. An outline is given of the principle of this technique, and the system build for the measurement is discussed.

This paper presents first clinical results of an in vivo experimental study on the detection of early pathological changes of rheumatoid arthritis (RA) using a near IR cw- transillumination method on finger joints (PIP). The inflammation of a joint system when caused by RA leads to changes in the synovial membrane and synovial. Measurements have shown that these rheumatic induced processes results in a variation in optical properties within the joint system. Using a cw system the PIP-joint is transilluminated with diode lasers at the articular cavity in order to use the entire scattered distribution of the transmitted radiation intensity for diagnostic purposes. The study includes results of in vivo measurements on 24 joints with known status and the evaluation of the feasibility of different distribution properties for detection of early RA.

Our aim is to reconstruct the optical parameters in a slice of a finger joint phantom for further investigations about rheumatoid arthritis (RA). Therefore, we have developed a flexible NIR scanning system in order to collect amplitude and phase delay of photon density waves in frequency-domain. A cylindrical finger joint phantom was embedded in a container of Intralipid solution due to the application of an inverse method for infinite geometry. The joint phantom was investigated by a laser beam obtaining several projections. The average optical parameters of each projection was calculated. Using different reconstruction techniques, e.g. ART and SIRT with a special projection operator, we reconstructed the optical parameters in a slice. The projection operator can be heuristically described by a photon path density function of a homogeneous media with infinite geometry. Applied to an object with an unknown distribution of optical parameters it calculates the expectation value of the investigated object. The potentials and limits of these fast reconstruction methods will be presented.

Optical coherence tomography (OCT) has shown great promise for non-invasive and contact-less imaging of subsurface soft tissues. However, the problem of low image contrast caused by speckle noise has limited its applications in diagnosis. This paper present a wavelet-based method designed to improve OCT image contrast by reducing speckle noise. After transforming the image into a set of sub-images with different resolution levels in wavelet domain, we threshold high-frequency coefficients nonlinearity in horizontal, vertical, and diagonal directions. The experimental results show that wavelet processing suppresses speckle noise in OCT images of soft tissue effectively, while maintaining the sharpness of image features.

Resolution and contrast of optical coherence tomography (OCT) images are degraded by multiple scattering processes that give a speckled appearance. In this paper we examine the spatial-frequency characteristics of tissue structure and speckle, with the goal of distinguishing speckle form structure for noise reduction by wavelet-based algorithms. Real and simulated images provide the basis for evaluating the performance of the algorithms and the finite-difference time-domain algorithm simulates propagation of the backscattering waves in OCT system.

Cyanine dyes are promising near-IR contrast agents because of their high molar absorption between 700 and 1000 nm, minimal phototoxicity and convenient synthetic availability. It is known that the derivatization of drugs or contrast agents with polyethylene glycol residues leads to enhanced retention in tumor tissue. The purpose of this study was to generate indotricarbocyanines with improved pharmacological properties enabling in vivo fluorescence detection of tumors. Several hydrophilic indotricarbocyanine- poly(ethylene glycol) conjugates of different molecular weight were synthesized and characterized physicochemically and photophysically in order to test their applicability as near IR contrast media.

The influence of the molecular weight of cyanine dye- poly(ethylene glycol) (PEG) conjugates on their pharmacokinetic behavior and on the contrast between malignant and normal tissue in fluorescence images was studied. PEG conjugates with a molecular weight ranging from 1800 to 40000 g mol^-1 were investigated in a rat model. A tunable, pulsed, solid-state laser system and an intensified CCD camera served to record fluorescence images of different tumor-bearing mice and rats. The time window of increased contrast between tumor and normal tissue in fluorescence images can be adjusted by the molecular weigh of PEG residues. Furthermore, we were able to demonstrate the visualization of subcutaneous blood vessels.

We report the development of a high temporal resolution fluorescence lifetime imaging (FLIM) system suing a time- gated image intensifier to provide whole field FLIM images. The gate width has been optimized to 110 ps, and changes in the environment of a fluorescent phantom, causing lifetime differences of 20 ps, have been detected. Environmental changes of the fluorescent indicator, Lucifer Yellow, have been sensed by measuring changes in its fluorescence lifetime in the presence of the protein albumin. We also present provisional fluorescence lifetime images of tissue constituents.

The optical and physico-chemical properties of the photosensitive dye - thiocarbocyanine in water solution as well as entrapped into the sol-gel matrices are examined. The absorption is measured for different pH of solutions. The changes caused by addition of ethanol and triton, are also investigated. It was observed that the photostability of the dye, in both water solution and sol-gel, depends strongly on pH and temperature. The higher photostability is observed for higher pH. It is shown that for thiocarbocyanine immobilized in sol-gel matrix, the photodegradation is slower than in the case of water and alcohol solutions.

Sodium nitroprusside (SNP) as an exogenous nitric oxide (NO) donor and N(omega) -nitro-L-arginine methyl ester(L-NAME) as NO synthesis inhibitor was driven into monkey cortex by iontophoresis, their effects on face recognition of monkey were observed, and neuron firing as well as neuron efficiency were monitored by fiberoptic-based multisensor during face recognition. The results show that L-NAME and low dose of SNP(5 nM) did not have any significant effect on face recognition and neuron efficiency, however high dose of SNP(50 nM) increased simultaneously both correct rate of face recognition and neuron efficiency, but not neuron firing. The results were discussed according to NO and its synthesis mechanism.

Up to now, fetal distress can only be detected by CTG and invasive fetal blood analysis. The Erlangen Microlightguide Photometer (EMPHO) allows the non-invasive measurement of local intracapillary haemoglobin concentration (Hb02). The Hb02-monitoring device was developed at the Institute of Physiology and Cardiology at the University ofErlangen by Professor Kessler4• With the EMPHO, we have measured the local oxygen supply at the fetal scalp during labor. The non-invasive measurements are based upon remission spectrophotometry with a visible wavelength of between 502 nm and 630 nm. A lightguide enlightens the tissue and the remitted light is collected by six fibers surrounding it. The lightguide is fixed with a holding device made of Polyacetale, which is casted in silicone rubber. The contact surface between the silicone rubber and the fetal scalp is additionally coated with a very soft silicone rubber gel (Sil-Gel 612®). Furthermore, a ring-shaped channel is integrated in the silicone rubber-cast to improve the adhesion by negative pressure. In a first clinical study, we measured on the scalp of 20 fetuses sub partu. The measuring time varied between 7 and 90 minutes. Measuring started after the rupture of the membrane as soon as the vertex was located one cm above the ischial spines. The measurement failed if maternal blood was contaminating the lightguides or if the sensor was disconnected. The coating appeared essential: only because of the use of soft gel the device was adhesive to the haired skin, and a dry local measuring area could be achieved. The HbOrvalues ranged from 10% to 70% in the second stage of labor. Fetal heart-rate decelerations of Type I caused no deterioration of the intracapillary haemoglobin oxygenation, but a continuous decrease during a prolonged deceleration could be observed. We were able to show that the EMPHO in connection with the sensor applicator guaranteed a continuous Hb02-monitoring during delivery in most of the cases. The course of the intracapillary haemoglobin oxygenation might be a useful additional parameter for fetal monitoring in the second stage of labor. Keywords: EMPHO, haemoglobin oxygenation, fetal monitoring, remission spectroscopy

T-cell contact with antigen-presenting B cells initiates an activation cascade which includes an increase in T-cell intracellular calcium and leads to T-cell proliferation and differentiation. We studied cell-cell contact requirements for T-cell activation using an optical trap to control the orientation of T-cell/B-cell pairs and fluorescence microscopy to measure subsequent T-cell(Ca²⁺)_i response. B cells or beads coated with antibodies to the T- cell receptor are trapped with a titanium-sapphire laser and placed at different locations along the T-cell, which has a polarized appearance defined by the shape and direction of crawling. T-cell (Ca²⁺)_i is detected as an emission shift from the combination of fura-red and oregon- green, two cytoplasmic (Ca²⁺)_i indicators. T- cells which are presented antigen at the leading edge have a higher probability of responding and a shorter latency of response than those contacting B-cells or beads with their trailing end.

Photoacoustic (PA) signals were used to detect and image optically absorbing structures in highly scattering media. Tissue phantoms were constructed from 10 μm diameter carbon fibres and nylon vessels containing blood or a variable dilution of Evens blue that were situated within a I% dilution oflntralipid A PVdF piezoelectric hydrophone with a bandwidth of 70 MHZ was used to detect the PA signals. A Q-switched frequency doubled Nd: Y AG laser provided 1 O ns pulses at 1 O Hz repetition rate and 532 nm wavelength. The sensitivity of the PA technique was demonstrated by the photoacoustic detection of single red blood cells that were situated on a glass plate in a PBS buffer. PA images of the samples were constructed from scanned array detection of the acoustic signals. The imaging algorithm is based on scanning synthetic delay-and-sum focus forming. The transducer directivity was simulated, verified and used to determine the weight factors of the algorithm. Threads and capillaries with various diameters situated at various depths have been imaged. The lateral resolution is limited by the diameter (200 μm) of the transducer. In the experimental images is shown that the depth resolution can be less than 10 μm. The accuracy of the source location reconstruction depends both on the method of signal processing and the PA signal duration. The PA images of larger blood vessels in phantom tissue show only the front and back side of these vessels due to the relatively low optical penetration depth in whole blood, acoustic interference and acoustic reflection at the walls of the vessels. The photoacoustic image of optically absorbing characters located at a depth of 1.8 mm and illuminated through 2 mm Intralipid dilution is presented. The results of this study are promising for the development ofphotoacoustic tomography. Keywords: Photoacoustics, imaging, phantom tissue, tomography, blood, piezoelectric detection.

The use of standard CCD cameras and image digitalization and processing on medical diagnosis are more and more frequent. The correction of human eye's refraction problems by the use of contact lenses is generalized. In spite its advantages in terms of users comfort, special care must be taken on its prescription and adaptation. Astigmatic eyes often place the highest problems. A careful assessment of the quality of the lens to cornea adaptation must to be performed. The basic and more traditional way to check the contact lens' fitting is to perform a fluorescein test. We intend to make the process more convenient for both patient and optometrist. The fluorescence images are acquired by a CCD camera and then digitized and processed in order to produce a semi- automated process.

Light-induced autofluorescence measurements were made on normal and tumor brain tissues to assess their spectroscopic properties and to verify the potential of this parameter for an intraoperative delineation of tumor resection margins. Spectrofluorometric analysis was performed both at the microscope on tissue sections from surgical resection, and on patients affected by glioblastoma, during surgical operation. Significant differences in autofluorescence emission properties were found between normal and tumor tissues in both ex vivo and in vivo measurements, indicating that the lesion can be distinguished from the informal surrounding tissues by the signal amplitude and the spectral shape. The non-invasiveness of the technique opens interesting prospects for improving the efficacy of neurosurgical operation, by allowing an intraoperative delimitation of tumor resection margins.

It is offered a new approach for diagnostics, photodynamic preventive maintenance and treatment of diseases of parodont and mucous membrane of mouth-based on luminescent diagnostics and photodynamic therapy.

We have developed a new method for scattering, absorbing and anisotropy coefficients distribution measurements. For investigation of scattering and fluorescent signal laser- fiber spectrum analyzer 'LESA-6' was applied. Some experiments were carried out using CCd-camera. The method is based on computation of 3D distribution of biological tissues optical properties. Computations are used optical images series. The method utilizes eight-flux theoretical model of light scattering. Measurement resluts of several scattering phantoms are shown. As inverse problems are mathematically incorrect, problem measurement results will be discussed.

Light microscopic dynamical images and amplitude-frequency spectra by computerized documentation were used for the experimental evidence that the biological rhythms and ciliary beating cycles can be used as relevant tool for the biomonitoring of environmental pollutants and influences. At present work some lower animals, invertebrates: Protozoa cells, Rotifera, Mollusca gill cilia epithelium, Polychaeta served the convenient model biosystem for investigations due there ciliary and contractile organs. The narrow Fourier- spectra bands were revealed for large number of organisms, which were shifted or diffused by heavy metal salts, ATP, Ca-, Mg-ions and organic mixture in concentrations 10^-2-10^-6 M. The three phase of the ciliary beating were obtained for single cilium. The group of cilia with a good metachronal coordination gave the narrow characteristic Fourier bands, while the perturbances from the external influences led to the spreading and shifting of the main bands. These effects could serve as test-methods for the environmental biomonitoring of pollutants.

The lipid peroxidation products of the lipofuscin type can be measured in plasma with the help of fluorimeters. Such products are increasing during whole plasm oxidation in parallel with other indices of lipid peroxidation damage. Preformed fluorescent products are located in all lipoprotein classes. The study of lipofuscin-type pigments fluorescence in HDL showed, that they contain substantial amounts of fluorescent compounds and that it rises in parallel with concentration of other lipid peroxidation products, especially thiobarbituric acid-reacting substances. Neither total plasma cholesterol, nor triglycerides influenced content of fluorescent products in HDL. The HDL subfractions contained different types of the fluorescent products but the bulk of these lipoproteins were almost free of them. The obtained data show that measurement of lipofuscin-type fluorescence in HDL gives a good and sensitive index of these lipoproteins damage by peroxidation.

The deformation of the facial bone made up of many complex- formed bones was measured and the role of suture considered with the mechanical response. The displacement of human dried facial bone was measured and considered under static loads by real time holographic interferometry. Materials were dried human skulls. Various loads were applied to the zygomatic, maxillary and the other facial bones by means of a loading apparatus. As the experimental result obtained from the load to the neighborhood of the temporo-zygomatic suture on the temporal bone, density of interference fringes increased on the temporal bone more than on the zygomatic and other facial bones and parallel interference fringes were observed on the temporal bone. The buffer effect on the temporo-zygomatic suture to the load was greater than the sutures of other facial bones. When the amount of load was increased on the same bone, it was expected that the zygomatic arch was broken independently as the type II of the fracture patterns by Knight and NOrth. When the neighborhood of the median suture on the maxillary bone was loaded, fine interference fringes were observed horizontally on the maxillary and zygomatic bones, while coarse interference fringes occurred on the frontal bone and the bilateral fracture pattern by LeFort was expected.

We demonstrate a coherence gating system to image through turbid media by using photorefractive holography with ultrashort pulses. Sub-100 micrometers depth-resolved images of 3D objects embedded in a scattering medium have been obtained. Using a long integration time in Rhodium-doped Barium Titanate, an image of a test chart has been obtained through 16 mean free paths of scattering medium. Real-time depth- resolved imaging through 13 mean free paths of scattering medium has been demonstrated using a fast response time photorefractive multiple quantum well device. We will discuss the trade-offs and limitations of these photorefractive media for this application.

First results of endoscopic applications of optical coherence tomography for in vivo studies of human mucosa in gastrointestinal and genital tracts are presented. A novel endoscopic OCT system has ben created that is based on the integration of a sampling arm of an all-optical-fiber interferometer into standard endoscopic devices using their biopsy channel to transmit low-coherence radiation to investigated tissue. We have studied mucous membranes of esophagus, stomach and uterine cervix as typical localization for carcinomatous processes. Images of tumor tissues versus healthy tissues have been recorded and analyzed. Violations of well-defined stratified healthy mucosa structure in cancerous tissue is distinctly seen by EOCT, thus making this technique promising for early diagnosis of tumors and precise guiding of excisional biopsy.