Radovan Hudák

Influence of Fixation on Magnetic Properties of Glass-Coated Magnetic Microwires for Biomedical Applications

The control of biomechanical processes in the tissue-implant interface and thermal changes created by friction or inflammatory processes in the implant and its environment represent the key validating processes of the postimplanting process. It is crucial for a patient and their health to minimize the invasiveness of the temperature measuring processes and the inner mechanical stress in the implant-tissue interface. For the purpose of these measurements, amorphous magnetic glass-coated microwires are the most suitable. Compared with other sensors, such as radio frequency identification sensors, the microwires have a significant advantage due to their dimensions (~2 cm × 50 μm) (because of which the sensor almost does not interfere with the inner implant structures), their production is relatively cheap, and only ~ 20 mm microwire is needed for the functional sensor. This paper is concerned with the testing of more types of microwire fixation in an implant and the impact of the fixation; it deals with necessary magnetic properties of a microwire and their dependence on the temperature. Microwire made of master alloy Fe78W5B17 was created and fixed in four ways: 1) on one end; 2) on two ends; 3) in the middle; and 4) along its full length. The results show that the optimal way of fixation is the one along the full length of a microwire; however, the final signal is influenced by both, the type and volume of the applied fixation material. The highest sensitivity of the designed microwire was in the range of 120-140 °C with no fixation and only with the full length fixation, this sensitivity decreased to 40-50 °C, which is a level close to the level required for biomedical applications (35-42 °C).

MATERIAL AND THERMAL ANALYSIS OF LASER SINTERTED PRODUCTS

Abstract Thermal analysis of laser processes can be used to predict thermal stresses and consequently deformation in a completed part. Analysis of temperature is also the basic for feedback of laser processing parameters in manufacturing. The quality of laser sintered parts greatly depends on proper selection of the input processing parameters, material properties and support creation. In order to relatively big heat stress in the built part during sintering process, the thermal simulation and thermal analysis, which could help better understand and solve the issue of parts deformations is very important. Main aim of presented work is to prepare input parameters for thermal simulations by the use of RadTherm software (Thermoanalytics Inc., USA), directly during the sintering process and after the process and find out the impact of the heat stress on a final shape and size of the prototype. Subsequently, an annealing process of constructed products after DMLS could be simulated and specified.

The methodics of medical thermography in the diagnostics of the human body musculoskeletal system

Medical thermography is a powerful tool for the study of surface temperature of the human body. It is non-invasive, non-radiation, painless and non-contact imaging technique with numerous medical applications including musculoskeletal system, its disorders and injuries. Often it is useful to cross-reference the resulting thermograms with visual images of the body; either to see which part of the musculoskeletal system is affected by a certain disease or injury or to judge the efficacy of the treatment. Presented paper deals with application of the thermal imaging to measure lower extremities surface temperature distribution in 20 healthy individuals. The aim was to asses the proper technical way of the measurement.

Application of medical thermography in the diagnostics of Carpal Tunnel Syndrome

Presented paper deals with infrared thermography (IRT) used for the diagnostics of Carpal Tunnel Syndrome (CTS). More studies on medical thermography in the relation with CTS diagnostics were published. Jesensek Papez B. et al. in 2008 and 2009 improved outcome with classification success rates near to or over 80% in dorsal segments of hand. The background of this study is the skin physiological temperature distribution difference on the dorsal hands and pathophysiological temperature distribution on hands with CTS and non-invasiveness and painlessness of IRT. For presented study, the database of 268 thermal images of the dorsal side of 120 healthy (n= 120) and 14 pathological hands (n=14) with clinically diagnosed CTS of 8 patients were examined. We observed the temperature distribution of the whole hand and the partial temperatures of the center point of carpals (D1), the center point of metacarpals (D2) and the finger tips of the third finger from proximal phalanges (D3), the intermediate phalanges (D4) to the distal phalanges (D5) and the Median Nerve Index (MI=(D1–D5)) were calculated. Results obtained from measurements of the five defined points on the dorsal side of hands showed, that the temperature of CTS hands is characterized by a higher temperature in the phalanges unlike the wrist (MI<0, 71,4%), while the temperature is the lowest on distal phalanges (D5) of healthy hands (MI≥0, 85,8%). The results showed that the skin temperatures of median nerve distribution area on dorsal hands were significantly different between CTS and the control group. The sensitivity of IRT in diagnostic process of CTS is 0,714. Results will be confirmed by further screening of statistically significant group of patients.

Embedded Tensile Strenght Test Machine FM1000 – An Upgrade of Measurement and Control

In order to compare the strengths of various materials it is necessary to carry out a standard form of test to establish their relative properties. The tensile test, compression test, bending, shearing and torsion tests are used for examining mechanical properties of biological materials. Except for non-destructive methods (optical, electromagnetic, sonic, thermal, infrared), destructive testing is another very important tool for the assessment of biomechanical properties and behavior of biomedical materials. The tensile strength test is one of the most common testing methods, which uses specific testing machines. Many tensile testing machines are equipped to plot a curve which shows the load or stress and the strain or movement that occurs during the test operation. In the testing operation, the load is increased gradually and the specimen will stretch or elongate in proportion to the tensile load. The load cells and extensometers measure the key parameters of force and deformation. The presented paper is a report which describes a specific and unique technical solution and upgrade of FM 1000 machine from the control and output processing point of view. Modern sensoric systems and I/O modules were used and custom software was developed. The fu

Segmentation of MRI Data to Extract the Blood Vessels Based on Fuzzy Thresholding

The article discusses the design of appropriate methodology of segmentation and visualization of MRI data to extract the blood vessels. The main objective of the proposed algorithm is effective separation individual vessels and adjecent structures. In clinical practice, it is necessary to assess the progress of the blood vessels in order to assess the condition of the vascular system. For physician who performs diagnosis is much more rewarding to perform analysis of an image that contains only vascular elements. The proposed method of image segmentation can effectively separate the individual blood vessels from surrounding tissue structures. The output of this analysis is the color coding of the input image data to distinguish contrasting behavior of individual vessels that are at the forefront of our concerns, the structures that we need in the picture.

Application of Magnetic Microwires in Titanium Implants - Conception of Intelligent Sensoric Implant

The idea of intelligent sensoric implant which enables to scan parameters from the human body wireless comes from analysis of studies descrbing reasons of implants rejection or loosening. Inflamations and incorrect biomechanical load are offen the reasons for surgery, where implant has to be removed or replaced. Presented study shows a concept of intelligent dental implant, where magnetic microwires are placed and fixed into titanium dental implant to get parameters from implant, tissue, or implant-tissue interaction. A part of the study shows preparation of magnetic microwires, measurement of physical quantities using bistabile magnetic microwires and realisation of the functional model of the sensor and experiments. Obtained results show, that utilization of magnetic microwires in implants for scanning of selected physiological or physical parameters is promising. The further researches in the field of fabrication technology, magnetic wires preparation and scanning processes to confirm an intelligent sensoric implant concept is necessary.

Thermographic atlas of the human body

The presented study deals with temperature distribution of healthy human bodies which were measured by infrared thermography. We used Infrared Imager with detector type 320×240 Focal Plane Array, Vanadium Oxide (VOx), Uncooled Microbolometer. A database of 240 thermograms from different position or locality of human body was created. The following eight views of human body were captured: TBA (Total Body — Anterior view), TBD (Total Body — Dorsal view), ToA (Torso — Anterior view), ToD (Torso — Dorsal view), DH (Dorsal side of Hand), PH (Palmar side of Hand), F (Foot) and FT (Facial Title). The database can be helpful in the diagnostics of many neurovascular and musculoskeletal diseases or injuries.

Medical thermography application in neuro-vascular deseases diagnostics

The measurement of the surface temperatures by infrared thermography is not frequently used in medicine despite of its safety, painlessness and invasiveness, good reproducibility and low running costs. Promising results have been achieved in nerve entrapment syndromes or neuropathies, although thermography has never represented as a real alternative to the electromyography. Here an attempt is described to improve the diagnosis of carpal tunnel syndrome by thermography using a computer-based system with special software to analyse obtained thermograms.

Usage of Industrial Computed Tomography for Evaluation of Custom-Made Implants

Development of additive technologies and biocompatible materials facilitated their use in the custom-made implants manufacture. Verification of custom-made implants manufactured using the additive manufacturing technologies is the key task to be fulfilled prior to the clinical application of an implant. It consists of parameters verification within individual steps, from a software design, through manufacturing, surface finishing, up to finalization of a medical product. The article presents possible uses of a 3D printing and the computed tomography (Metrotom 1500, Carl Zeiss, Germany) for the verification of selected parameters of customized implants manufactured using the Direct Metal Laser Sintering (DMLS) technology with the EOSINT M280 equipment (EOS GmbH, Germany) from the biocompatible titanium alloy Ti-6Al-4V (Grade 5). The article describes the possibilities of the computed tomography use in the verification of implant shapes and external dimensions, as well as internal structure. The internal structure means the implant porosity assessment.