Antoni Nowakowski

Thermal Parametric Imaging in the Evaluation of Skin Burn Depth

The aim of this paper is to determine the extent to which infrared (IR) thermal imaging may be used for skin burn depth evaluation. The analysis can be made on the basis of the development of a thermal model of the burned skin. Different methods such as the traditional clinical visual approach and the IR imaging modalities of static IR thermal imaging, active IR thermal imaging and active-dynamic IR thermal imaging (ADT) are analyzed from the point of view of skin burn depth diagnostics. In ADT, a new approach is proposed on the basis of parametric image synthesis. Calculation software is implemented for single-node and distributed systems. The properties of all the methods are verified in experiments using phantoms and subsequently in vivo with animals with a reference histopathological examination. The results indicate that it is possible to distinguish objectively and quantitatively burns which will heal spontaneously within three weeks of infliction and which should be treated conservatively from those which need surgery because they will not heal within this period

Properties of a polyethyleneimine-based sensor for measuring medium and high relative humidity

In this paper a method of preparing polyethyleneimine films, which improves the water resistance of polymer humidity sensors, is proposed. The polyethyleneimine was cross-linked at elevated temperature using 1,4-butanediol diglycidyl ether, both being dissolved in dimethylsulfoxide. The optimum composition of polymer and optimum reaction temperature were obtained. Resistive-type sensors have been prepared by dip coating. The sensor preserves excellent durability in high humidities or even after immersion in water. The electrical properties of the sensors were investigated by impedance spectroscopy.

Active dynamic infrared thermal imaging in burn depth evaluation.

The aim of this study was to find the relationship between active dynamic thermography (ADT) with cold excitation and burn depth. This new modality of evaluation of burns seems to be an attractive proposal for quantitative classification, allowing proper choice of burn wound treatment: conservative or surgical, especially compared with static thermography. The work was an in vivo experiment on domestic pigs, and a small number of patients were also diagnosed as part of the study. Statistical analysis showed a high correlation between the ADT synthetic parameter—thermal time constant, &tgr;—and the classification of burn wounds that were predicted to heal within 3 weeks and so were treated conservatively and those that were predicted to not heal within 3 weeks and so were surgically treated. The results of the study show an accuracy of 60.7% for clinical evaluation, 69.6% for static thermography, 83.0% for ADT, and 84.0% for histopathologic assessment. The authors have concluded that the ADT method with cold excitation is suitable for the qualitative and quantitative assessment of burn depth.

Active dynamic thermography in cardiosurgery

The aim of this study is development and analysis of applicability of new tools for continuous inspection of open-heart cardio-surgical interventions, suitable in clinical environment. Our notice is concentrated on IR-thermal imaging for monitoring of invasive surgical interventions as CABG in treatment of ischaemia and other heart malfunctions. In this presentation preliminary results of in-vivo experiments on animals with the use of IR thermal camera and newly developed procedures of active dynamic thermography are discussed.

Analysis of transient thermal processes for improved visualization of breast cancer using IR imaging

We discuss limitations of the known methods of IR imaging in diagnostics of breast cancer. In conclusion we show that for practical reasons one requires new approaches because the known methods based on simple observation of external temperature distribution are not fully effective. Even advanced pattern recognition could not help too much for static images. We ask the question: may active dynamic thermography, known in nondestructive testing of materials, be of any help? Analysis of thermal transients forced by external thermal excitation shows even on simple models, that one may expect visible improvement in resolution after such excitation. Applied models allow analysis of both, static as well as active thermograms. Basing on the models one may recognize elements of the internal structure of a breast not visible using static pictures. This new in clinical practice method seems to be promising, but still needs more studies.

Medical Active Thermography - A New Image Reconstruction Method

A new method of image reconstruction for active, pulse thermography is presented. Based on experimental results the thermal model of the observed object is proposed. Studies on thermal transients basing on the FEM object model are presented. Examples of reconstructed images are presented and described for phantoms and for in-vivo measurements. Possible applications are discussed.

Properties of a lithium solid electrolyte gas sensor based on reaction kinetics

Principle of operation, construction and properties of a gas sensor based on lithium ion-conductor solid electrolyte (Lisicon) are presented. The sensor has been prepared using thick film technology. Its working principle is based on electric current acquisition, while a voltage ramp is applied to the sensor. The current–voltage plot has a unique shape, which depends on the surrounding gas type and its concentration. Results of measurements conducted in mixtures of high purity gases—nitrogen dioxide, sulfur dioxide, carbon dioxide and synthetic air of controlled concentration—over a wide range of temperatures are presented and discussed.

Optical excitation methods in active dynamic thermography in medical diagnostics

The dynamic thermography technique, extensively used for non-destructive testing in industry, applied to a human body can be very attractive for medical diagnostics purposes. The study presented in this paper introduces methodology of dynamic thermography to applications in medical diagnostics. Review of properties of several excitation sources and techniques as well as some experimental results are given.

Active Dynamic Thermography - Problems of implementation in medical diagnostics

Implementation of the method called Active Dynamic Thermography (ADT) in medical diagnostics of some specific diseases is here discussed. In skin burn diagnostics a method giving objective information what is the burn depth is a real challenge as until now there are not such methods approved in clinical practice. We have shown that ADT is a proper tool to give an answer to the question of non invasive, objective and quantitative determination of burns depth and the severity of a tested wound. The method may be also used to diagnose breast cancer and in some other applications. We implemented in clinics a prototype set based on ADT procedures for skin burn diagnostics. Practical conditions for reliable use of ADT in burn diagnostics are here discussed. The instrumentation and procedures applied in animal experiments and clinical tests are described. Basic problems limiting practical implementation of ADT are underlined. Especially the choice of external excitation seems to be not a trivial task; though we proved a very high importance of cooling.

Infrared thermography: applications in heart surgery

Infrared thermography has become a way to monitor thermal abnormalities present in number of diseases and physical injuries. It is used as an aid to diagnosis, prognosis and therapy. Results obtained using the last generation of equipment (computer assisted thermographic systems, detectors without liquid nitrogen cooling system) and new techniques as dynamic thermography with independent source of driving radiation shows that it is a reliable tool for medical assessment and diagnosis. Most important--the Infrared Thermography is a non-invasive measurement technique, with non-stress for patients. This paper describes Intraoperative Thermoangiography during coronary bypass surgery.