Tadeusz Palko

Comparison of multiscale entropy of healthy and cancer tissue imaged by optical polarimeter

Polarimetric observations of neoplastic changes in biological tissue may support its early diagnostics. A human breast tissue is observed in polarized light. Obtained images of healthy and cancer cases are decomposed by a trous wavelet algorithm. When multiscale representation of the tissue images is found their autocorrelation functions are compared. A comparison of new observables, multiscale entropy and mean entropy vectors is presented. It is found that these observables may indicate tissue changes as well as its condition.

Cardiac ventricle contour reconstruction in ultrasonographic images using bayesian constrained spectral method

We propose a novel method of active spectral segmentation of cardiac ventricle by application of Bayesian inference adapted to contour detection in speckled ultrasonographic cardiological data. We discuss the advantages and limitations of this method and describe possible further developments.

Computer Program for Automatic Identification of Artifacts in Impedance Cardiography Signals Recorded during Ambulatory Hemodynamic Monitoring

The aim of this work was to design and verify a computer program which could detect artifacts in impedance cardiography (ICG) signals. It contains a procedure for creating a pattern of one typical cycle of the ICG trace and enabling the classification of each heart evolution as either a valid one or an artifact. It proposed an index characterizing the shape of the ICG signal pattern. The user can significantly influence the classification process by modifying the initial parameters of the patterns. The program automatically detects the characteristic points in the electrocardiographic (ECG) and ICG signals (dZ/dt) necessary for calculation of hemodynamic parameters and allows the user to browse previously recorded data. The program calculates basic cardiac hemodynamic parameters: heart rate (HR), pre-ejection period (PEP), left ventricular ejection time (ET), stroke volume (SV), cardiac output (CO) and other derivative ones, basing on previously classified data. We described the program structure and the operation of its main functions. The application is written in C++ using the Qt graphic library. It is flexible and can be modified or extended to suit the user’s needs. The analysis’ findings (based on on example data) are also presented.

Identification of the Sources of Artefacts in the Holter-Type Impedance Cardiography Recordings

The evaluation of the rate of artefacts during ambulatory impedance cardiography monitoring is one of the fundamental question regarding the applicability of that method. It is also important to know which type of the patient movements create the noisiest recordings. With the aim to evaluate these uncertainties 14 healthy males (23-28 years) underwent examination (using ReoMonitor) in supine position, in moving during supine position, sitting, reading when sitting, walking and walking on stairs. Each of the part of the protocol lasted 3 minutes. The ratio of artefact free cycles to the total number of cycles was calculated for each evolution. It was averaged for each 60 seconds. For this ratio the parameters of descriptive statistics were calculated for the entire group of subjects. The maximum rate of artefacts free cycles was 1.0 and the minimal ratio was 0.25. The average ratio for all manoeuvres was 0.84±0.13. The data shown that the rate of artefacts is not very high and the system might be used to collect signals in a laboratory and in the field for monitoring changes in cardiovascular parameters.

Influence of Non-Optimal Levels of Electrical Stimulation in Cochlear Implantees on Hearing Benefits

To obtain hearing benefits after cochlear implantation it is crucial to optimally fit the system to the individual need of each patient (Wasowski et al., 2004). Great variability between patients and changes in optimal values that can be observed in time make this a difficult task. To assure optimal fitting of the system, fitting procedure that contains psychophysics and objective measurements was introduced in the Institute of Physiology and Pathology of Hearing. However, it is still very interesting to find out how non-optimal fitting may influence hearing benefits.

RC Model-based Comparison Tests of the Added Compliance Method with Computer Simulations and a Standard Method

RC Model-based Comparison Tests of the Added Compliance Method with Computer Simulations and a Standard Method Ventilation of the lungs involves the exchange of gases during inhalation and exhalation causing the movement of respiratory gases between alveolars and the atmosphere as a result of a pressure drop between alveolars and the atmosphere. During artificial ventilation what is most important is to keep specific mechanical parameters of the lungs such as total compliance of the respiratory system Cp (consisting of the lung and the thorax compliances) and the airway resistance Rp when the patient is ventilated. Therefore, as the main goal of this work and as the first step to use our earlier method of added lung compliance in clinical practice was: 1) to carry out computer simulations to compare the application of this method during different expiratory phases, and 2) to compare this method with the standard method for its accuracy. The primary tests of the added-compliance method of the main lung parameters measurement have been made using the RC mechanical model of the lungs.

A Multiscale Entropy Analysis of Physiological and Malignant Breast Tissues Imaged by an Optical Polarimeter

A Multiscale Entropy Analysis of Physiological and Malignant Breast Tissues Imaged by an Optical Polarimeter There are indications in the literature that polarimetric observations of neoplastic changes in biological tissues may support early diagnosis of cancer. In the present studies, samples of human breast tissue were observed in a polarized light. The images of healthy and malignant tissues were decomposed by a à trous wavelet algorithm. When a multiscale representation of tissue images is determined, their autocorrelation functions are also compared. A comparison of new observables, multiscale entropy and mean entropy vectors are presented. It was found that these observables might be considered as possible indicators of the malignant transformation in tissue.

Module for measurement of CO2 concentration in exhaled air

The objective of this work consists in working out of a detection module for capnography (carbon dioxide concentration measurement in anaesthesiology and intensive care). The principle of operation of the module consists of the NDIR method. The basic assumption for construction of this model was using of directly modulated thermal IR source in it. A few models of IR sources were worked out. Their heaters were made from thick platinum layers and foil. Limits of modulation frequency for IR sources were greater than 30 Hz. The detection module consists of an optical part, analogue electronics and microprocessor system with a suitable program. The time dependent concentration of CO2, end tidal concentration of CO2, mean concentration of N2O and breath frequency are output values of the detection module. Measurements are executed 30 times per second. The accuracy of CO2 concentration measurement equals to 5%.

Medical Engineering in Poland

Medical physics and medical engineering in Poland has almost 80 years of history. Education in biomedical engineering, started in 1946 at the Warsaw University of Technology. During years of activity in this field, the group of specialists was growing up and in 1965 the Polish Society of Medical Physics was founded. Actually, more than 10 universities offer education in biomedical engineering and more than 20 are working in this area. The current program offers the first degree study (engineer), the second degree (MSc) and third degree (PhD). The regulation of Ministry of Health introduced in 2002 the specialization in medical engineering as a profession in clinical environment, for engineers and medical physicists, similar to that in medical education system. Structure of education program of medical engineering specialization in Poland has been prepared according to medical needs, Bologna Declaration, IFMBE recommendations and practical possibilities.

Graphene electrodes for voltammetric measurements in biological fluids

Purpose – The aim of this paper was to verify applicability of graphene-based sensors for voltammetric and amperometric measurements of low-concentration compounds in biological fluids. Design/methodology/approach – Using the screen printing method, electrochemical sensors were manufactured on polymethylmetacrylate foil using a paste consisting of organic solvents and graphene nanopetals. As the model of a biological fluid tear film was chosen, the compound chosen as the analyte was H2O2, which is produced in oxidation of biological compounds. Tear film analog was prepared, in which, the measurements were carried out in a wide range of concentrations to determine the oxidation potential of H2O2 through square-wave voltammetry. The second series of amperometric measurements was carried out for concentrations between 0 and 30 μM/L, which is the lower range of physiological glucose concentration in tear films. Findings – The sensors presented linearity for concentrations from 0 to 3.5 per cent. Mean linear c...