Optical Coherent Tomography (OCT) is an imaging techniqu that enables a range of clinical applications where imaging can be carried out in situ and in real time. In OCT, cross-section images are generated by transverse scanning light beam across investigated tissue and by measuring the delay and magnitude of the back-scattered light. Among several detection techniques which can be used to implement OCT, Optical Low-Coherent Reflectometry (OLCR) or Optical Frequency Domain Reflectometry (OFDR) are the most promising. The paper presents merits of both techniques.

Optical tomography method of imaging of absorbing objects in high scattering medium is presented. The method was tested with laser diode modules lasing at 660 and 785 nm and phantom with Intralipid as a medium simulating optical properties of tissue. A probe with absorbing liquids simulating object was used. Results of imaging were very good for objects placed outside of central part in phantom.

The paper deals with the optimal formulation of the heat transfer inverse problem in biological tissues. The aim is to reconstruct the actual distribution of thermal properties within a tested object. The decision vector may be chosen depending on the knowledge about an investigated object. The number of unknown model elements may be chosen. For a low number, wide knowledge about the object is required. For a too high number of unknown elements the quality of the reconstruction algorithm may be decreased or even it may lead to non-uniqueness of the stated problem. Methods used for investigation of phantoms and for non-invasive skin burn diagnostic are presented.

Optical measurement methods are indispensable tool in biomedical research, providing invaluable information on optical properties of biological tissues. However, the application of these techniques is a big challenge, as most tissues are highly scattering materials whose optical properties cannot be measured in a straightforward way, due to multiple scattering of photons. Therefore, new optical measurement techniques and methods for highly scattering media are being developed to address this problem. One of the very promising techniques is time-of-flight spectroscopy. The paper presents problems encountered in reconstruction of basic optical parameters of tissues or other highly scattering materials from optical time-of-flight spectroscopy measurement data. To estimate the reconstruction accuracy of optical parameters (i.e. absorption coefficient, scattering coefficient, anisotropy factor and refractive index) the test data were generated by a computer program simulating light propagation in highly scattering material by Monte Carlo method. Following, a set of computer programs based on diffusion equation and optimization algorithms such as simplex method and genetic method were used to reconstruct optical parameters from the test data. Finally, by comparing reconstructed optical parameters with those used for generation of the test data, the accuracy of reconstructing algorithms it was estimated.

Fluorescence and absorption spectra of camptothecin -- anticancer alkaloid, are analyzed in this paper. Camptothecin exists in two forms: lactone and carboxylate. Only lactone form is biologically active. In physiological fluids at pH 7.4 lactone form hydrolyses and converts into carboxylate form. There are some differences in shapes between fluorescence and absorption spectra of lactone and carboxylate form. In the deactivation process fluorescence and absorption spectra evaluate. Thanks to the factor analysis of series of spectra recorded during the process of hydrolysis one can follow the concentration of both forms in the solution. Described method could be useful in determining of kinetics of deactivation process and competitive with the HPLC method.

The fluorescence excitation spectra of camptothecins -- alkaloids which have anticancer properties, are analyzed in this paper. Camptothecins exist in two forms -- biologically active lactone form and inactive carboxylate form. In fluids of pH 7,4 lactone forms hydrolyze and convert into carboxylate forms. There are some differences in shapes between fluorescence excitation spectra of lactone and carboxylate forms. One can observe evolution of fluorescence spectra during hydrolysis of camptothecins. Using principal component analysis and factor analysis to the set of fluorescence spectra recorded during process of hydrolysis of camptothecins one can determine the temporary concentration of lactone and carboxylate forms in solutions of pH 7,4 and obtain kinetics of deactivation of this compounds.

The paper shows the results of the research on the active dynamic thermography used for diagnostics of onychomycosis and progress of the healing process. It seems that the most essential factor affecting the development of mycosis in nails is the microcirculation in the tissue close to the nail. Active dynamic thermography may prove to be a new diagnostic method and a sufficient tool for measurements of this parameter.

Background: Although there are several methods for atherosclerosis detection available, none of them seems to be accurate enough to identify the vulnerable atheroscleroitc plaque. Photodynamic diagnosis (PDD) and therapy (PDT) -- a new method evaluated for neoplasms treatment is a modern approach to detecting and treating atherosclerosis. Aim: The purpose of this study was to assess in vitro the capability of PDD with use of chlorin e6 to recognize atherosclerotic plaque and its usefulness as a feedback system for photoangioplasty treatment. Methods: 30 specimens of human aorta. The samples were soaked with chlorin e6 and then washed out. The luminescence spectra were then collected. All samples were examined with light microscopy. Results: Tissue fluorescence is seen as green light. We noted a very strong red fluorescence of chlorin e6 originating from lipid reach plaque. We established a quantitative factor which would be the ratio R of chlorin e6 red intensity in its 660 nm maximum compared to the area of green luminescence centered at 515 nm. The highest value of the ratio was reached at atheromatous samples, then calcified and normal ones R₂ = 3.51 ± 0.62, R₃ = 1.63 ± 0.31, R₁ = 1.51 ± 0.15 respectively. Statistically significant difference was noted between group two and one and between group two and three R₂ = 3.51 ± 0.62 vs R₃ = 1.63 ± 0.31 (p < 0,05); R₂ = 3.51 ± 0.62 vs. R₁ = 1.51 ± 0.15 (p<0.05) respectively. Conclusions: the following in vitro study confirms that photosensitizer chlorin e6 accumulates within atheromatous plaque. It may be a specific tool for atheromatous and normal or calcified segments discrimination. The advantage of the above method is a possibility of a real time imaging followed by targeted therapy of various forms and stages of atherosclerosis.

The procedure of percutaneous coronary intervention is associated with the 30% risk of restenosis in the dilatated coronary artery. in order to minimize its occurrence we developed the method of intracoronary low power laser irradiation and called it the photoremodling. We developed and constructed at total set-up for the intravascular illumination. It consists of the laser diode connected with a multimode step-index silica fiber 200/270 μm terminated with a special fiber diffuser, which allows to irradiate homogeneously a coronary vessel in the place of dilatation. The diffuser is inserted into the coronary vessel by a modificated angioplasty catheter. Till now PTCA plus photoremodeling procedures have been carried out in 40 patients (28 with stent implantation and 12 with balloon angioplasty). We did not observed any side effects and complications of the procedure. All patients were qualified for 6 months follow-up, which was terminated in 19 cases with a control coronarography. We did not find any case of restenosis in the stent group. In the group of patients after balloon angioplasty restenosis rate was 25%. The new method of treatment is safe. The preliminary results seem to be beneficial especially in the case of stent implantation.

This paper proposes non-invasive solution to the problem of sleep apnea diagnosis especially in small children when sudden death syndrome is suspected. Plethysmographic wave analysis and digital signal processing algorithms are applied in order to find the effect invoked by respiratory movements of sleeping patients so as to diagnose the sleep apnea syndrome. The practical results of finding solution to problems mentioned above will be the possibility of algorithms implementation in a portable intelligent measurement system with a non-invasive monitoring of respiratory action. It works without any disturbances of sleep and respiratory movements especially in small children what could make possible in the future when continuous monitoring were applied to prevent sudden death syndrome occurrence.

Time-resolved optical measurements allow for evaluation of optical properties of the tissue (in particular, absorption and reduced scattering coefficient). A four-channel time-resolved spectroscopic system for measurements of the tissue optical properties is presented. Four semiconductor diode lasers were used for emission of picosecond pulses at wavelengths of 633, 687, 784 and 832 nm. Optical fibers were applied to deliver the laser light into the tissue studied. The diffusely reflected light was transmitted to the photodetectors through fiber bundles. Four photomultiplier tubes were used for light detection and four independent time-correlated single photon counting boards were applied to obtain distributions of times of flight of photons. Measurements on liquid phantoms were carried out to test the temporal resolution and stability of the system and to demonstrate its usefulness in non-invasive determination of optical properties of the tissue.

The laser Doppler method offers a non-invasive, real time technique for monitoring of blood perfusion in microcirculation. In practical measurements the perfusion index is given only in relative values. Thus, accurate and reproducible results can be only obtained when using a well controlled stimulation test. The aim of this study was evaluation of the thermal stimulation test, which is frequently used to investigate microcirculation in patients with Raynaud's syndrome. Three types of thermal tests, in which air or water with temperature in range 5°C - 40°C were used. Ten normal volunteers and fifteen patients with clinical symptoms of the primary Raynaud's syndrome were enrolled in this study. To estimate skin microcirculation changes during the thermal test, the multichannel laser Doppler system and laser Doppler scanner were used. The obtained results were analyzed from the point of view of the efficiency of these methods and the thermal provocative tests in differentiation of normal subjects and patient with Raynaud's syndrome.

A monomode and multimode fiber white-light interferometric temperature sensor for biomedical applications is presented. The sensor uses a low-finesse Fabry-Perot interferometer working in reflective mode. Dependence of material parameters on fringe visibility is discussed and both construction of the sensor has been optimized with respect to fringe visibility. This new sensor system is expected to be a practical approach for many medical applications.

Principles of integrated optical sensors based on polarimetric interferometry are presented in the paper. A wide area of their applications in biochemistry includes monitoring of protein concentration in solutions, detection of antibodies as well as indirect investigation of chemical reactions, based on precise measurement of complex refractive index. In order to address a problem of irreversibility of wide group of biological processes and chemical reactions as well as to decrease cost of the sensors, authors propose to develop disposable measurement converters and to use optical components made from sol-gel derived hybrid polymers. The technology of hybrid materials synthesis and subsequent planar waveguides manufacturing as well as their properties are shown.

Bolometers are widely used as thermal detectors, e.g. in thermovision, medicine, astronomy etc. Among them there are thermistor-like devices consisting of the absorbing radiant power thermally sensitive films, deposited on the substrate. To meet the requirements made for bolometers, their material should have adequate parameters and characteristics. In this paper some thermal characteristics and parameters of the conducting, perovskite type ABO₃ non-stoichiometric oxides LSCO and LSFO are discussed to evaluate their usefulness in the construction of bolometers.

Construction and properties of electrocatalytic gas sensor based on samarium-doped ceria solid electrolyte are described. Electrocatalytic sensors form a new group of gas sensor, which employ kinetics of controlled chemical reaction. Measurements in mixtures of synthetic air and nitrogen dioxide are shown. Current-voltage response has unique shape, which depends on NO₂ concentration. Influence of voltage sweep rate and temperature on sensor characteristics is reported. The constructed sensor can be used for nitrogen dioxide monitoring.

The effect of humidity influence on characteristics of a ceramic sensor with a porous dielectric Al₂O₃ layer is presented. Influence of chosen electrolytic process parameters on electrical properties of the sensor is shown. The experimental data of two groups of sensors are interpreted using two, known from literature, electric equivalent circuits.

Paper presents some new ideas introducing automatic understanding of the medical images semantic content. The idea under consideration can be found as next step on the way starting from capturing of the images in digital form as two-dimensional data structures, next going throw images processing as a tool for enhancement of the images visibility and readability, applying images analysis algorithms for extracting selected features of the images (or parts of images e.g. objects), and ending on the algorithms devoted to images classification and recognition. In the paper we try to explain, why all procedures mentioned above can not give us full satisfaction in many important medical problems, when we do need understand image semantic sense, not only describe the image in terms of selected features and/or classes. The general idea of automatic images understanding is presented as well as some remarks about the successful applications of such ideas for increasing potential possibilities and performance of computer vision systems dedicated to advanced medical images analysis. This is achieved by means of applying linguistic description of the picture merit content. After this we try use new AI methods to undertake tasks of the automatic understanding of images semantics in intelligent medical information systems. A successful obtaining of the crucial semantic content of the medical image may contribute considerably to the creation of new intelligent multimedia cognitive medical systems. Thanks to the new idea of cognitive resonance between stream of the data extracted form the image using linguistic methods and expectations taken from the representation of the medical knowledge, it is possible to understand the merit content of the image even if the form of the image is very different from any known pattern.

Image content-based description methods and content-based retrieval methods are presented. Region extraction framework is introduced including a region description using run-length codes. Query algebra is presented in details including query classification and specification of its parameters (e.g. similarity measures, descriptors). Results on description speed, retrieval speed and retrieval quality are presented and discussed.

Image registration algorithms should be robust against partly erroneous and inconsistent data. The evidence accumulation mechanism known as the Hough Transform (HT) finds the solution indicated by the largest consistent subset of the data. The important case of feature-based registration under the simplified affine transformation, that is, translation, rotation and isotropic scaling, can be easily stated in the terms of HT. Until recently, the use of HT in the considered application was prohibited by excessive computational requirements, but the development of the hardware permanently relieves these limitations. Three versions of the HT, both in the crisp and fuzzy version, were examined against the test images: the Generalized HT (GHT), the Modified Iterated HT (MIHT), and the version called here the Direct Accumulation HT (DAHT), known also as GIPSC on the grounds of photogrammetry. The results indicate that the fuzzy DAHT is robust for over 50% of errors in data, fuzzy GHT up to nearly 30%, and that all the crisp versions as well as the fuzzy MIHT are fragile at least for some examples. The practical applicability of the DAHT and GHT is shown for hierarchical registration of simulation and portal images used in quality assessment of oncological radiotherapy.

This paper offers an algorithm for determining the blood flow parameters in the neck vessel segments using a single (optimal) measurement plane instead of the usual approach involving four planes orthogonal to the artery axis. This new approach aims at significantly shortening the time required to complete measurements using Nuclear Magnetic Resonance techniques. Based on a defined error function, the algorithm scans the solution space to find the minimum of the error function, and thus to determine a single plane characterized by a minimum measurement error, which allows for an accurate measurement of blood flow in the four carotid arteries. The paper also comprises a practical implementation of this method (as a module of a larger imaging-measuring system), including preliminary research results.

Method of the face reconstruction based on deformation of the triangle mesh of the model face. It is fast method with space partitioning according to Manchester points.

A reconstruction algorithm based on applying of a current pattern using electrodes is considered in the paper. A resulting voltage distribution between electrodes is measured. To improve an accuracy of the reconstructed image two FEM models are used -- a dense one in the forward problem and coarse one in inverse problem. A one-step version of the algorithm is examined and the results are compared with these obtained from iterative version of the algorithm. The reconstruction algorithm based on Levenberg-Marquardt approach is utilized. It has been found that the errors of images depend on object properties and can vary significantly in one-step version of reconstruction algorithm.

Modern radiation therapy tools allow a precise delivery of a high dose to a target area (so-called planning target volume -- PTV) and spare, at the same time, critical organs in the vicinity of cancerous lesions. One of the tools of conformal therapy is a multi-leaf collimator, which provides the opportunity to optimally adjust the therapeutic field to the tumor area. More difficult areas for radiation therapy include: mamma, after BCT, and chest after mammectomy with regional lymph nodes. The objective of the study is to present technical and physical aspects of breast carcinoma irradiation when applying a multi-leaf collimator. The following techniques were applied: (a) the isocentric technique of tangent fields (from two to four) for the mamma after BCT; (b) the method of a common isocenter, for the areas of mamma and for regional lymph nodes; (c) the technique of complementary photon + electron fields, for the area of chest after mammectomy and lymph nodes. The presented techniques were implemented as standard procedures in the preparation of breast carcinoma radiation treatment in the Lower Silesian Oncology Center.

The paper presents the experimental validation of the coronary blood flow measured from coronarographic images. The method of flow measurement earlier presented is based on elements of the indicator-dilution theory and on the idea of using two sequences of images obtained during standard coronarographic examination. Measurements of the image intensity along the cross-section lines of the artery were performed on the sequence with the standard injection of contrast and with the small quantity of slowly injected contrast. These two sequences enable the construction of the contrast relative concentration curve in the defined earlier cross-section vs. time. The global volumetric blood flow can be calculated as a ratio of the quantity of the indicator injected during the indicator-dilution sequence by the value of the area under concentration curve. Experimental validation was performed using a simple artery model. Results of the flow calculation for five cross-section lines positioned in different intensity levels regions of the image show that the error is below 20%.

The article presents new multislice/multidetector scanners used in X-Ray computed tomography. After a short technological review, the role and the importance of this technology in functional heart diagnostics is presented and discussed. All applications are illustrated by the studies performed on 16 rows scanners.

The microwave radiation effects on EEG-signal have been studied by comparison with photo-stimulaton. The study of photos-stimulation effects at 16 Hz frequency and microwave radiation stimulation effects at 450 MHz modulated with 7 Hz frequency show fractal dimension increase.

The subject of the paper is devoted to a modern diagnostic method called the endoscopic ultrasonography (EUS) that is still not widely implemented in many countries. This method bases on two imaging techniques: videoendoscopy and ultrasonography, making possible effective aiding of diagnostics as well as evaluating possibilities of performing radical surgical therapy. Rotating USG probes enable acquiring images vertical to an axis for the round angle area. Small diameters and adequate frequencies of these microprobes make possible their deep penetration into such difficult sites as the biliary and pancreatic ducts. The EUS advantages are presented here on the basis of several examples of real minimally invasive interventions as well diagnostic procedures practiced by the authors. EUS has allowed precise diagnostics without disturbances occurring at conventional ultrasound imaging. The presented images concern EUS used for examination of different digestive tract diseases, including biliary and pancreatic ducts.

Growing popularity of non invasive medical techniques makes accurate and reliable diagnostics based on image data more and more important. It is necessary to implement modern, highly automated image processing techniques. Information theory and statistics provide a means to create such systems. In this paper we discuss application of entropy and mutual information in segmentation and registration of real world medical images.