Krzysztof Opieliński - Academia.edu (original) (raw)

Papers by Krzysztof Opieliński

Archives of Acoustics, 2013

The paper presents an analysis of the results of ultrasound transmission tomography (UTT) imaging... more The paper presents an analysis of the results of ultrasound transmission tomography (UTT) imaging of the internal structure of a breast elastography phantom used for biopsy training, and compares them with the results of CT, MRI and, conventional US imaging; the results of the phantom examination were the basis for the analysis of UTT method resolution. The obtained UTT, CT and MRI images of the CIRS Model 059 breast phantom structure show comparable (in the context of size and location) heterogeneities inside it. The UTT image of distribution of the ultrasound velocity clearly demonstrates continuous changes of density. The UTT image of derivative of attenuation coefficient in relation to frequency is better for visualising sharp edges, and the UTT image of the distribution of attenuation coefficient visualises continuous and stepped changes in an indirect way. The inclusions visualized by CT have sharply delineated edges but are hardly distinguishable from the phantom gel backgrou...

Archives of Acoustics

This paper presents and analyses the results of a simulation of the acoustic field distribution i... more This paper presents and analyses the results of a simulation of the acoustic field distribution in sectors of a 1024-element ring array, intended for the diagnosis of female breast tissue with the use of ultrasonic tomography. The array was tested for the possibility to equip an ultrasonic tomograph with an additional modality-conventional ultrasonic imaging with the use of individual fragments (sections) of the ring array. To determine the acoustic field for sectors of the ring array with a varying number of activated ultrasonic transducers, a combined sum of all acoustic fields created by each elementary transducer was calculated. By the use of MATLAB software, a unique algorithm was developed, for a numerical determination of the distribution of pressure of an ultrasonic wave on any surface or area of the medium generated by the concave curvilinear structure of rectangular ultrasound transducers with a geometric focus of the beam. The analysis of the obtained results of the acoustic field distribution inside the ultrasonic ring array used in tomography allows to conclude that the optimal number of transducers in a sector enabling to obtain ultrasound images using linear echographic scanning is 32 ≤ n ≤ 128, taking into account that due to an increased temporal resolution of ultrasonic imaging, this number should be as low as possible.

Applied Sciences

As early as 1774, the application of ultrasound in the animal world was noted by the Italian natu... more As early as 1774, the application of ultrasound in the animal world was noted by the Italian naturalist Lazzaro Spallanzani, who discovered that bats move using ultrasonic waves [...]

Advances in Intelligent Systems and Computing, 2018

This paper presents an algorithm which allows a multi-para-meter in vivo visualization of a breas... more This paper presents an algorithm which allows a multi-para-meter in vivo visualization of a breast structure by fusing two quantitative ultrasound tomography images and by automatically identifying areas of fat and glandular tissue, as well as areas of benign or malignant lesions, with the background of the reflection ultrasound tomography image of structures scattering ultrasonic waves. The threshold values for identifying particular tissue areas in quantitative images were adjusted to patient age using empirical linear functions. The viability of the algorithm was confirmed in preliminary in vivo breast ultrasound tomography screening tests. The obtained results allow a prediction that the ultrasound tomography scanner, which uses the here-presented algorithm to fuse the reconstructed images, and which is currently deployed by the private investor in cooperation with the authors of this paper, will provide a new standard in breast cancer diagnostics through fast and cheap screening tests.

Applied Sciences, 2022

Ultrasound breast tomography (UBT) is a promising quantitative imaging method. It allows for prec... more Ultrasound breast tomography (UBT) is a promising quantitative imaging method. It allows for precise analysis of ultrasound velocity distribution, which is related to tissue density and elasticity, enabling cancer detection. Only a few centers around the world have a prototype of the device for in vivo breast ultrasound tomography imaging. The quality of images reconstructed from measurements of ultrasound pulse transit times is adversely affected by the refraction of beam rays on the breast immersed in water. Refraction can be reduced using waveform tomography, ray-tracing, and ray-linking methods. However, this requires the acquisition of a pre-reconstructed pattern and is limited by extreme computational costs. In this study, the effect of refraction on transit time measurements of ultrasound passing through the female breast was analyzed under immersion conditions in water. It was found that the refraction causes the highest measurement errors in the area of the water/breast int...

Applied Sciences, 2022

Three-dimensional automated breast ultrasound (ABUS) systems seem to offer excellent results in b... more Three-dimensional automated breast ultrasound (ABUS) systems seem to offer excellent results in breast cancer screening tests and its early detection, comparable to handheld ultrasound B-mode scanning, with the benefit of saving physician time and reducing handheld ultrasound issues. Nevertheless, the ABUS systems are not very popular, due to the cost and very narrow application. The multi-angle conventional 3D ultrasound compound imaging method (MACUI) is intended for use with standard B-mode scanners in order to reduce cost but preserve the advantages of ABUS systems. The rotational probe movement is utilized in order to collect images for the three-dimensional reconstruction of the scanned tissue’s anatomy. The authors evaluate the capabilities to increase the scanned volume and quality of reconstructions, which are limited in current MACUI implementations, with a probe tilt and shift. The study shows and discusses the results of the imaging using different probes available for S...

Sensors, 2020

In this paper, a method for estimating snow pressure reflection coefficient based on non-contact ... more In this paper, a method for estimating snow pressure reflection coefficient based on non-contact ultrasound examination is described. A constant frequency and air-coupled ultrasound pulses were used in this study, which incorporates a parametric method for reflected energy estimation. The experimental part was carried out in situ in the Antarctic, where the snow parameters were measured along with meteorological data. The proposed method represents a promising alternative for estimating the snow-water equivalent, since it uses a parametric approach, which does not require measurements of absolute values for acoustic pressure.

Advances in Intelligent Systems and Computing, 2018

Doppler Tomography (DT) is an innovative method that can be used for imaging the internal structu... more Doppler Tomography (DT) is an innovative method that can be used for imaging the internal structure of tissue immersed in water. In order to reconstruct the image, the Doppler signal is necessary, recorded by a two-transducer ultrasonic probe. This method can be used in in vivo medical diagnostics. In this paper, in order to analyse the possibility of DT imaging in circular geometry, a simulation-based method for determining the Doppler signal has been developed. Additionally, an algorithm determining the frequency value for particular inclusions at a given moment of rotation of the probe was developed. For the purposes of reconstructing the cross-sectional area of the examined object, a fast tomographic algorithm was used. On the basis of the results obtained, analyses were made and a discussion was conducted on the possibilities and limitations in imaging the structure of objects using this method, depending on the way of acquiring the Doppler signal.

Advances in Intelligent Systems and Computing, 2016

The imaging of blood flow in blood vessels is the classic use of the Doppler effect in medicine. ... more The imaging of blood flow in blood vessels is the classic use of the Doppler effect in medicine. This method involves a transceiver ultrasonic probe which generates the acoustic signal in the form of a continuous wave which is reflected by moving biological components and returns with changed frequency. This effect can also be used to obtain the image of stationary tissue section, by moving the probe around the object. Such an imaging method is called Doppler Tomography (DT), or Continuous Wave Ultrasonic Tomography (CWUT). Currently, there is no comprehensive study of this method in the literature. This paper shows a simulation model which allows the reconstruction of the image consisting of infinitely small objects which evenly disperse the ultrasound wave. In order to assess the possibility of using DT in medicine, the obtained images were analyzed based on the parameters input to the reconstruction algorithm. Additionally, the exemplary waveform of a useful signal recorded of the real object of a small diameter is included.

Acta Acustica united with Acustica, 2018

Computerized Medical Imaging and Graphics, 2017

Highlights  We designed the multimodal ultrasound tomography system for breast diagnosis.  Our ... more Highlights  We designed the multimodal ultrasound tomography system for breast diagnosis.  Our device is one of several unique innovatory devices under development worldwide.  We present novel ultrasound images of an in vivo breast cyst and malignant changes.  We show the set of 3 complementary qualitative and quantitative images which allow to recognize and differentiate breast lesions.  We present the approach to the recognition of breast lesions using a new type of imaging.  The obtained transmission images of ultrasound speed distribution show good correlation of glandular tissue areas with their visualization on MRI images.  Our system can be used for the fast and cost effective in vivo breast screening as a noninvasive, harmless, painless and safe diagnostic tool.

Applied Acoustics, 2017

This paper addresses the problem related to the interpretation of the results of actual snowfall ... more This paper addresses the problem related to the interpretation of the results of actual snowfall measurements performed with two different configurations of the compensation methods for changeable climatic conditions. The paper also presents the operating principle of an ultrasound sensor for monitoring snow layer (on the air-side). In particular, the paper includes a graphic representation of the results of measurements performed in measurement stations located in Poland and at Spitsbergen. The two compensation methods (temperature and parametric) were tested for their effectiveness in different, changeable climatic conditions. The measurement results confirm that the applied compensation methods are useful in minimizing the measurement error for snow layer thickness measured on the air-side.

Archives of Acoustics, 2016

Linear arrays of ultrasonic transducers are commonly used as ultrasonic probes in medical diagnos... more Linear arrays of ultrasonic transducers are commonly used as ultrasonic probes in medical diagnostics for imaging the interior of a human body in vivo. The crosstalk phenomenon occurs during the operation of transducers in which electrical voltages and mechanical vibrations are transmitted to adjacent components. As a result of such additional excitation of the transducers in the array, the directivity characteristics of the aperture used changes, and consequently there is interference with properoperation of a given array and the emergence of distortions in the obtained ultra sound image that reduce its quality. This paper studies the manner of propagation of mechanical crosstalk in the designed model of a linear array of ultrasonic transducers on the basis of unwanted signals, which appeared on elementary piezo-electric transducers when power is supplied to the selected transducer in the array. The universal model of linear array of ultrasonic transducers, which has been developed...

Archives of Acoustics, 2008

In this work, formulas were presented, which allow modelling of linear and nonlinear propagation ... more In this work, formulas were presented, which allow modelling of linear and nonlinear propagation of ultrasonic wave in a biological medium, by simulating the shape of pulses which propagate in this medium. Analysed and measured in chosen biological media using transmission method, the linear and nonlinear ultrasonic pulses were modelled by means of developed formulas. Very good compatibility of the representation was achieved both in the area of time and frequency. In case of biological media causing high attenuation of ultrasonic wave, reduction of mid frequency in the receiving pulse caused by attenuation dispersion was observed.

Archives of Acoustics, 2015

Ultrasonic projection imaging is similar to X-ray radiography. Nowadays, ultrasonic projection me... more Ultrasonic projection imaging is similar to X-ray radiography. Nowadays, ultrasonic projection methods have been developed in the set-up of multi-element flat arrays with miniature transducers, where one of the array acts as a transmitter and the other one is a receiver. In the paper, a new method of the projection imaging using a 1024-element circular ultrasonic transducer array is presented. It allows the choice of a projection scanning plane for any angle around a studied object submerged in water. Fast acquisition of measurement data is achieved as a result of parallel switching of opposite transmitting and receiving transducers in the circular array and vertical movement of the array. The algorithm equalizing the length of measurement rays and the distances between them was elaborated for the reconstruction of projection images. Projection research results of breast phantom obtained by means of the elaborated measurement set-up and compared with mammography simulations (acquire...

Computerized medical imaging and graphics : the official journal of the Computerized Medical Imaging Society, Jan 21, 2015

Nowadays, in the era of common computerization, transmission and reflection methods are intensive... more Nowadays, in the era of common computerization, transmission and reflection methods are intensively developed in addition to improving classical ultrasound methods (US) for imaging of tissue structure, in particular ultrasound transmission tomography UTT (analogous to computed tomography CT which uses X-rays) and reflection tomography URT (based on the synthetic aperture method used in radar imaging techniques). This paper presents and analyses the results of ultrasound transmission tomography imaging of the internal structure of the female breast biopsy phantom CIRS Model 052A and the results of the ultrasound reflection tomography imaging of a wire sample. Imaging was performed using a multi-modal ultrasound computerized tomography system developed with the participation of a private investor. The results were compared with the results of imaging obtained using dual energy CT, MR mammography and conventional US method. The obtained results indicate that the developed UTT and URT m...

Advances in Intelligent Systems and Computing, 2014

Today, in the age of computerization, experts not only strive to perfect methods of ultrasonograp... more Today, in the age of computerization, experts not only strive to perfect methods of ultrasonographic (US) imaging of tissue structure, but also intensively develop transmission methods, focusing especially on ultrasound transmission tomography (UTT) (analogous to X-ray computed tomography - CT) and ultrasound reflection tomography (URT) based on synthetic aperture method used in radar imaging. The following paper presents and analyses the results of ultrasound transmission tomography of the internal structure of a biopsy CIRS Model 052A breast phantom. The imaging was performed with an internally designed ultrasound computer tomography research system. The obtained results were compared to the imaging results from dual energy CT, MR mammography and traditional US.

Ultrasonics, 2002

The effective ultrasonic energy radiation into the air of piezoelectric transducers requires usin... more The effective ultrasonic energy radiation into the air of piezoelectric transducers requires using multilayer matching systems with accurately selected acoustic impedances and the thickness of particular layers. This problem is of particular importance in the case of ultrasonic transducers working at a frequency above 1 MHz. Because the possibilities of choosing material with required acoustic impedance are limited (the counted values cannot always be realised and applied in practice) it is necessary to correct the differences between theoretical values and the possibilities of practical application of given acoustic impedances. Such a correction can be done by manipulating other parameters of matching layers (e.g. by changing their thickness). The efficiency of the energy transmission from the piezoceramic transducer through different layers with different thickness enabling a compensation of non-ideal real values by changing their thickness was computer analysed. The result of this analysis is the conclusion that from the technological point of view a layer with defined thickness is easier and faster to produce than elaboration of a new material with required acoustic parameter.

Ultrasonics, 2002

In different solutions of ultrasonic transducers radiating acoustic energy into the air there occ... more In different solutions of ultrasonic transducers radiating acoustic energy into the air there occurs the problem of the proper selection of the acoustic impedance of one or more matching layers. The goal of this work was a computer analysis of the influence of acoustic impedance on the transfer function of piezoceramic transducers equipped with matching layers. Cases of resonance and non-resonance matching impedance in relation to the transfer function and the energy transmission coefficient for solid state-air systems were analysed. With stable thickness of matching layers the required shape of the transfer function can be obtained through proper choice of acoustic impedance were built (e.g. maximal flat function). The proper choice of acoustic impedance requires an elaboration of precise methods of synthesis of matching systems. Using the known matching criteria (Chebyshev's, DeSilets', Souquet's), the transfer function characteristics of transducers equipped with one, two, and three matching layers as well as the optimisation methods of the energy transmission coefficient were presented. The influence of the backside load of the transducer on the shape of transfer function was also analysed. The calculation results of this function for different loads of the transducer backside without and with the different matching layers were presented. The proper load selection allows us to obtain the desired shape of the transfer function, which determines the pulse shape generated by the transducer.

Archives of Acoustics, 2013

The paper presents an analysis of the results of ultrasound transmission tomography (UTT) imaging... more The paper presents an analysis of the results of ultrasound transmission tomography (UTT) imaging of the internal structure of a breast elastography phantom used for biopsy training, and compares them with the results of CT, MRI and, conventional US imaging; the results of the phantom examination were the basis for the analysis of UTT method resolution. The obtained UTT, CT and MRI images of the CIRS Model 059 breast phantom structure show comparable (in the context of size and location) heterogeneities inside it. The UTT image of distribution of the ultrasound velocity clearly demonstrates continuous changes of density. The UTT image of derivative of attenuation coefficient in relation to frequency is better for visualising sharp edges, and the UTT image of the distribution of attenuation coefficient visualises continuous and stepped changes in an indirect way. The inclusions visualized by CT have sharply delineated edges but are hardly distinguishable from the phantom gel backgrou...

Archives of Acoustics

This paper presents and analyses the results of a simulation of the acoustic field distribution i... more This paper presents and analyses the results of a simulation of the acoustic field distribution in sectors of a 1024-element ring array, intended for the diagnosis of female breast tissue with the use of ultrasonic tomography. The array was tested for the possibility to equip an ultrasonic tomograph with an additional modality-conventional ultrasonic imaging with the use of individual fragments (sections) of the ring array. To determine the acoustic field for sectors of the ring array with a varying number of activated ultrasonic transducers, a combined sum of all acoustic fields created by each elementary transducer was calculated. By the use of MATLAB software, a unique algorithm was developed, for a numerical determination of the distribution of pressure of an ultrasonic wave on any surface or area of the medium generated by the concave curvilinear structure of rectangular ultrasound transducers with a geometric focus of the beam. The analysis of the obtained results of the acoustic field distribution inside the ultrasonic ring array used in tomography allows to conclude that the optimal number of transducers in a sector enabling to obtain ultrasound images using linear echographic scanning is 32 ≤ n ≤ 128, taking into account that due to an increased temporal resolution of ultrasonic imaging, this number should be as low as possible.

Applied Sciences

As early as 1774, the application of ultrasound in the animal world was noted by the Italian natu... more As early as 1774, the application of ultrasound in the animal world was noted by the Italian naturalist Lazzaro Spallanzani, who discovered that bats move using ultrasonic waves [...]

Advances in Intelligent Systems and Computing, 2018

This paper presents an algorithm which allows a multi-para-meter in vivo visualization of a breas... more This paper presents an algorithm which allows a multi-para-meter in vivo visualization of a breast structure by fusing two quantitative ultrasound tomography images and by automatically identifying areas of fat and glandular tissue, as well as areas of benign or malignant lesions, with the background of the reflection ultrasound tomography image of structures scattering ultrasonic waves. The threshold values for identifying particular tissue areas in quantitative images were adjusted to patient age using empirical linear functions. The viability of the algorithm was confirmed in preliminary in vivo breast ultrasound tomography screening tests. The obtained results allow a prediction that the ultrasound tomography scanner, which uses the here-presented algorithm to fuse the reconstructed images, and which is currently deployed by the private investor in cooperation with the authors of this paper, will provide a new standard in breast cancer diagnostics through fast and cheap screening tests.

Applied Sciences, 2022

Ultrasound breast tomography (UBT) is a promising quantitative imaging method. It allows for prec... more Ultrasound breast tomography (UBT) is a promising quantitative imaging method. It allows for precise analysis of ultrasound velocity distribution, which is related to tissue density and elasticity, enabling cancer detection. Only a few centers around the world have a prototype of the device for in vivo breast ultrasound tomography imaging. The quality of images reconstructed from measurements of ultrasound pulse transit times is adversely affected by the refraction of beam rays on the breast immersed in water. Refraction can be reduced using waveform tomography, ray-tracing, and ray-linking methods. However, this requires the acquisition of a pre-reconstructed pattern and is limited by extreme computational costs. In this study, the effect of refraction on transit time measurements of ultrasound passing through the female breast was analyzed under immersion conditions in water. It was found that the refraction causes the highest measurement errors in the area of the water/breast int...

Applied Sciences, 2022

Three-dimensional automated breast ultrasound (ABUS) systems seem to offer excellent results in b... more Three-dimensional automated breast ultrasound (ABUS) systems seem to offer excellent results in breast cancer screening tests and its early detection, comparable to handheld ultrasound B-mode scanning, with the benefit of saving physician time and reducing handheld ultrasound issues. Nevertheless, the ABUS systems are not very popular, due to the cost and very narrow application. The multi-angle conventional 3D ultrasound compound imaging method (MACUI) is intended for use with standard B-mode scanners in order to reduce cost but preserve the advantages of ABUS systems. The rotational probe movement is utilized in order to collect images for the three-dimensional reconstruction of the scanned tissue’s anatomy. The authors evaluate the capabilities to increase the scanned volume and quality of reconstructions, which are limited in current MACUI implementations, with a probe tilt and shift. The study shows and discusses the results of the imaging using different probes available for S...

Sensors, 2020

In this paper, a method for estimating snow pressure reflection coefficient based on non-contact ... more In this paper, a method for estimating snow pressure reflection coefficient based on non-contact ultrasound examination is described. A constant frequency and air-coupled ultrasound pulses were used in this study, which incorporates a parametric method for reflected energy estimation. The experimental part was carried out in situ in the Antarctic, where the snow parameters were measured along with meteorological data. The proposed method represents a promising alternative for estimating the snow-water equivalent, since it uses a parametric approach, which does not require measurements of absolute values for acoustic pressure.

Advances in Intelligent Systems and Computing, 2018

Doppler Tomography (DT) is an innovative method that can be used for imaging the internal structu... more Doppler Tomography (DT) is an innovative method that can be used for imaging the internal structure of tissue immersed in water. In order to reconstruct the image, the Doppler signal is necessary, recorded by a two-transducer ultrasonic probe. This method can be used in in vivo medical diagnostics. In this paper, in order to analyse the possibility of DT imaging in circular geometry, a simulation-based method for determining the Doppler signal has been developed. Additionally, an algorithm determining the frequency value for particular inclusions at a given moment of rotation of the probe was developed. For the purposes of reconstructing the cross-sectional area of the examined object, a fast tomographic algorithm was used. On the basis of the results obtained, analyses were made and a discussion was conducted on the possibilities and limitations in imaging the structure of objects using this method, depending on the way of acquiring the Doppler signal.

Advances in Intelligent Systems and Computing, 2016

The imaging of blood flow in blood vessels is the classic use of the Doppler effect in medicine. ... more The imaging of blood flow in blood vessels is the classic use of the Doppler effect in medicine. This method involves a transceiver ultrasonic probe which generates the acoustic signal in the form of a continuous wave which is reflected by moving biological components and returns with changed frequency. This effect can also be used to obtain the image of stationary tissue section, by moving the probe around the object. Such an imaging method is called Doppler Tomography (DT), or Continuous Wave Ultrasonic Tomography (CWUT). Currently, there is no comprehensive study of this method in the literature. This paper shows a simulation model which allows the reconstruction of the image consisting of infinitely small objects which evenly disperse the ultrasound wave. In order to assess the possibility of using DT in medicine, the obtained images were analyzed based on the parameters input to the reconstruction algorithm. Additionally, the exemplary waveform of a useful signal recorded of the real object of a small diameter is included.

Acta Acustica united with Acustica, 2018

Computerized Medical Imaging and Graphics, 2017

Highlights  We designed the multimodal ultrasound tomography system for breast diagnosis.  Our ... more Highlights  We designed the multimodal ultrasound tomography system for breast diagnosis.  Our device is one of several unique innovatory devices under development worldwide.  We present novel ultrasound images of an in vivo breast cyst and malignant changes.  We show the set of 3 complementary qualitative and quantitative images which allow to recognize and differentiate breast lesions.  We present the approach to the recognition of breast lesions using a new type of imaging.  The obtained transmission images of ultrasound speed distribution show good correlation of glandular tissue areas with their visualization on MRI images.  Our system can be used for the fast and cost effective in vivo breast screening as a noninvasive, harmless, painless and safe diagnostic tool.

Applied Acoustics, 2017

This paper addresses the problem related to the interpretation of the results of actual snowfall ... more This paper addresses the problem related to the interpretation of the results of actual snowfall measurements performed with two different configurations of the compensation methods for changeable climatic conditions. The paper also presents the operating principle of an ultrasound sensor for monitoring snow layer (on the air-side). In particular, the paper includes a graphic representation of the results of measurements performed in measurement stations located in Poland and at Spitsbergen. The two compensation methods (temperature and parametric) were tested for their effectiveness in different, changeable climatic conditions. The measurement results confirm that the applied compensation methods are useful in minimizing the measurement error for snow layer thickness measured on the air-side.

Archives of Acoustics, 2016

Linear arrays of ultrasonic transducers are commonly used as ultrasonic probes in medical diagnos... more Linear arrays of ultrasonic transducers are commonly used as ultrasonic probes in medical diagnostics for imaging the interior of a human body in vivo. The crosstalk phenomenon occurs during the operation of transducers in which electrical voltages and mechanical vibrations are transmitted to adjacent components. As a result of such additional excitation of the transducers in the array, the directivity characteristics of the aperture used changes, and consequently there is interference with properoperation of a given array and the emergence of distortions in the obtained ultra sound image that reduce its quality. This paper studies the manner of propagation of mechanical crosstalk in the designed model of a linear array of ultrasonic transducers on the basis of unwanted signals, which appeared on elementary piezo-electric transducers when power is supplied to the selected transducer in the array. The universal model of linear array of ultrasonic transducers, which has been developed...

Archives of Acoustics, 2008

In this work, formulas were presented, which allow modelling of linear and nonlinear propagation ... more In this work, formulas were presented, which allow modelling of linear and nonlinear propagation of ultrasonic wave in a biological medium, by simulating the shape of pulses which propagate in this medium. Analysed and measured in chosen biological media using transmission method, the linear and nonlinear ultrasonic pulses were modelled by means of developed formulas. Very good compatibility of the representation was achieved both in the area of time and frequency. In case of biological media causing high attenuation of ultrasonic wave, reduction of mid frequency in the receiving pulse caused by attenuation dispersion was observed.

Archives of Acoustics, 2015

Ultrasonic projection imaging is similar to X-ray radiography. Nowadays, ultrasonic projection me... more Ultrasonic projection imaging is similar to X-ray radiography. Nowadays, ultrasonic projection methods have been developed in the set-up of multi-element flat arrays with miniature transducers, where one of the array acts as a transmitter and the other one is a receiver. In the paper, a new method of the projection imaging using a 1024-element circular ultrasonic transducer array is presented. It allows the choice of a projection scanning plane for any angle around a studied object submerged in water. Fast acquisition of measurement data is achieved as a result of parallel switching of opposite transmitting and receiving transducers in the circular array and vertical movement of the array. The algorithm equalizing the length of measurement rays and the distances between them was elaborated for the reconstruction of projection images. Projection research results of breast phantom obtained by means of the elaborated measurement set-up and compared with mammography simulations (acquire...

Computerized medical imaging and graphics : the official journal of the Computerized Medical Imaging Society, Jan 21, 2015

Nowadays, in the era of common computerization, transmission and reflection methods are intensive... more Nowadays, in the era of common computerization, transmission and reflection methods are intensively developed in addition to improving classical ultrasound methods (US) for imaging of tissue structure, in particular ultrasound transmission tomography UTT (analogous to computed tomography CT which uses X-rays) and reflection tomography URT (based on the synthetic aperture method used in radar imaging techniques). This paper presents and analyses the results of ultrasound transmission tomography imaging of the internal structure of the female breast biopsy phantom CIRS Model 052A and the results of the ultrasound reflection tomography imaging of a wire sample. Imaging was performed using a multi-modal ultrasound computerized tomography system developed with the participation of a private investor. The results were compared with the results of imaging obtained using dual energy CT, MR mammography and conventional US method. The obtained results indicate that the developed UTT and URT m...

Advances in Intelligent Systems and Computing, 2014

Today, in the age of computerization, experts not only strive to perfect methods of ultrasonograp... more Today, in the age of computerization, experts not only strive to perfect methods of ultrasonographic (US) imaging of tissue structure, but also intensively develop transmission methods, focusing especially on ultrasound transmission tomography (UTT) (analogous to X-ray computed tomography - CT) and ultrasound reflection tomography (URT) based on synthetic aperture method used in radar imaging. The following paper presents and analyses the results of ultrasound transmission tomography of the internal structure of a biopsy CIRS Model 052A breast phantom. The imaging was performed with an internally designed ultrasound computer tomography research system. The obtained results were compared to the imaging results from dual energy CT, MR mammography and traditional US.

Ultrasonics, 2002

The effective ultrasonic energy radiation into the air of piezoelectric transducers requires usin... more The effective ultrasonic energy radiation into the air of piezoelectric transducers requires using multilayer matching systems with accurately selected acoustic impedances and the thickness of particular layers. This problem is of particular importance in the case of ultrasonic transducers working at a frequency above 1 MHz. Because the possibilities of choosing material with required acoustic impedance are limited (the counted values cannot always be realised and applied in practice) it is necessary to correct the differences between theoretical values and the possibilities of practical application of given acoustic impedances. Such a correction can be done by manipulating other parameters of matching layers (e.g. by changing their thickness). The efficiency of the energy transmission from the piezoceramic transducer through different layers with different thickness enabling a compensation of non-ideal real values by changing their thickness was computer analysed. The result of this analysis is the conclusion that from the technological point of view a layer with defined thickness is easier and faster to produce than elaboration of a new material with required acoustic parameter.

Ultrasonics, 2002

In different solutions of ultrasonic transducers radiating acoustic energy into the air there occ... more In different solutions of ultrasonic transducers radiating acoustic energy into the air there occurs the problem of the proper selection of the acoustic impedance of one or more matching layers. The goal of this work was a computer analysis of the influence of acoustic impedance on the transfer function of piezoceramic transducers equipped with matching layers. Cases of resonance and non-resonance matching impedance in relation to the transfer function and the energy transmission coefficient for solid state-air systems were analysed. With stable thickness of matching layers the required shape of the transfer function can be obtained through proper choice of acoustic impedance were built (e.g. maximal flat function). The proper choice of acoustic impedance requires an elaboration of precise methods of synthesis of matching systems. Using the known matching criteria (Chebyshev's, DeSilets', Souquet's), the transfer function characteristics of transducers equipped with one, two, and three matching layers as well as the optimisation methods of the energy transmission coefficient were presented. The influence of the backside load of the transducer on the shape of transfer function was also analysed. The calculation results of this function for different loads of the transducer backside without and with the different matching layers were presented. The proper load selection allows us to obtain the desired shape of the transfer function, which determines the pulse shape generated by the transducer.