Prof. Leszek Filipczyński, Ph.D., Dr. Habil., Eng.


Doctoral thesis
1955Przetwarzanie elektroakustyczne i promieniowanie jod akustycznych dla celów impulsowej defektoskopii ultradźwiękowej 
supervisor -- Prof. Ignacy Malecki, Ph.D., Dr. Habil., Eng., IPPT PAN
5 
Professor
1962Title of professor
Other
1969Corresponding Member of Polish Academy of Sciences
1976Member of Polish Academy of Sciences

Supervision of doctoral theses
1.1990Litniewski Jerzy  Sygnał z mikroskopu akustycznego przy pracy poza ogniskiem i jego zastosowanie do interpretacji obrazów biologicznych 
2.1984Piechocki Maciej  Ultradźwiękowe metody dopplerowskie pomiaru z zaburzonych przepływów krwi 
3.1980Maruk Tamara  Dynamiczne ogniskowanie wiązki ultradźwiękowej za pomocą przetworników pierścieniowych 
4.1978Markiewicz Anna  Analiza impulsowych nadawczo-odbiorczych układów ultradźwiękowych do celów diagnostyki medycznej 
5.1977Powałowski Tadeusz  Pomiar przepływu cieczy ultradźwiękową dooplerowską metodą fali ciągłej 
6.1977Etienne Jerzy  Wybrane zagadnienia z zastosowania ultradźwięków w położnictwie 
7.1976Nowicki Andrzej  Ultradźwiękowa dopplerowska impulsowa metoda i aparatura do pomiarów przepływu krwi w układzie krążenia 
8.1972Peńsko Bogumił  Teoria i badania eksperymentalne ultradźwiękowych układów drgań giętnych z punktu widzenia ich zastosowań do badań zmęczeniowych lin 
9.1970Łypacewicz Grażyna  Problemy elektroakustyczne ultradźwiękowych głowic stosowanych w diagnostyce medycznej 

Recent publications
1.Wójcik J., Filipczyński L., Nowicki A., Foundation of the new method of numerical calculations of the nonlinear acoustics fields, HYDROACOUSTICS, ISSN: 1642-1817, Vol.16, pp.253-262, 2013
Abstract:

We explain, motivation behind this work and briefly describe foundation of new method which we have developed for efficient solution in PC environment of the nonlinear propagation equation with the boundary conditions applied for both circular and not circular transducers (like array). Comparison between new and old method will be presented for strongly nonlinear disturbance. At the end we will demonstrate the results of the numerical calculations of the nonlinear field propagating from the array.

Keywords:

Nonliear propagation, Envelope waves, Fast calculations

Affiliations:
Wójcik J.-IPPT PAN
Filipczyński L.-IPPT PAN
Nowicki A.-IPPT PAN
2.Wójcik J., Nowicki A., Lewin P.A., Bloomfield P.E., Kujawska T., Filipczyński L., Wave envelopes method for description of nonlinear acoustic wave propagation, Ultrasonics, ISSN: 0041-624X, DOI: 10.1016/j.ultras.2006.04.001, Vol.44, pp.310-339, 2006
Abstract:

A novel, free from paraxial approximation and computationally efficient numerical algorithm capable of predicting 4D acoustic fields in lossy and nonlinear media from arbitrary shaped sources (relevant to probes used in medical ultrasonic imaging and therapeutic systems) is described. The new WE (wave envelopes) approach to nonlinear propagation modeling is based on the solution of the second order nonlinear differential wave equation reported in [J. Wojcik, J. Acoust. Soc. Am. 104 (1998) 2654-2663; V.P. Kuznetsov, Akust. Zh. 16 (1970) 548-553]. An incremental stepping scheme allows for forward wave propagation. The operator-splitting method accounts independently for the effects of full diffraction, absorption and nonlinear interactions of harmonics. The WE method represents the propagating pulsed acoustic wave as a superposition of wavelet-like sinusoidal pulses with carrier frequencies being the harmonics of the boundary tone burst disturbance. The model is valid for lossy media, arbitrarily shaped plane and focused sources, accounts for the effects of diffraction and can be applied to continuous as well as to pulsed waves. Depending on the source geometry, level of nonlinearity and frequency bandwidth, in comparison with the conventional approach the Time-Averaged Wave Envelopes (TAWE) method shortens computational time of the full 4D nonlinear field calculation by at least an order of magnitude; thus, predictions of nonlinear beam propagation from complex sources (such as phased arrays) can be available within 30-60 min using only a standard PC. The approximateratio between the computational time costs obtained by using the TAWE method and the conventional approach in calculations of the nonlinear interactions is proportional to (1/N)**2, and in memory consumption to 1/N where N is the average bandwidth of the individual wavelets. Numerical computations comparing the spatial field distributions obtained by using both the TAWE method and the conventional approach (based on a Fourier series representation of the propagating wave) are given for circular source geometry, which represents the most challenging case from the computational time point of view. For two cases, short (2 cycle) and long (8 cycle) 2 MHz bursts, the computational times were 10 min and 15 min versus 2 h and 8 h for the TAWE method versus the conventional method, respectively.

Keywords:

Nonliear propagation, Envelope waves, Fast calculations

Affiliations:
Wójcik J.-IPPT PAN
Nowicki A.-IPPT PAN
Lewin P.A.-Drexel University (US)
Bloomfield P.E.-Drexel University (US)
Kujawska T.-IPPT PAN
Filipczyński L.-IPPT PAN
3.Kujawska T., Wójcik J., Filipczyński L., Possible Temperature Effects Computed for Acoustic Microscopy Used For Living Cells, ULTRASOUND IN MEDICINE AND BIOLOGY, ISSN: 0301-5629, DOI: 10.1016/j.ultrasmedbio.2003.08.018, Vol.30, No.1, pp.93-101, 2004
Abstract:

Imaging of living cells or tissues at a microscopic resolution, where GHz frequencies are used, provides a foundation for many new biological applications. The possible temperature increase causing a destructive influence on the living cells should be then avoided. However, there is no information on possible local temperature increases at these very high frequencies where, due to strongly focused ultrasonic beams, nonlinear propagation effects occur. Acoustic parameters of living cells were assumed to be close to those of water; therefore, the power density of heat sources in a water medium was determined as a basic quantity. Hence, the numerical solution of temperature distributions at the frequency of 1 GHz was computed for high and low powers generated by the transducer equal to 0.32 W and 0.002 W. In the first case, typical nonlinear propagation effects were demonstrated and, in the second one, propagation was almost linear. The focal temperature increase obtained in water equaled 14°C for the highest possible theoretical repetition frequency of fr = 10 MHz and for the thermal insulation at the sapphire lens-water boundary. Simultaneously, the scanning velocity of the tested object was assumed to be incomparably low in respect to the acoustic beam velocity. The maximum temperature increase in water occurred exactly at this boundary, being equal there to 20°C. It was shown that, first of all, the very high absorption of water was significant for the temperature distribution in the investigated region, suppressing the focal temperature peaks. Because the temperature increases are proportional to the repetition frequency, so for example, at its practical value of fr = 0.1 MHz, all temperature increases will be 100 times lower than listed above. For the low transducer power of 0.002 W, the corresponding temperature increases were about 140 times lower than those for the high power of 0.32 W. The presented solutions are devoted mainly to the reflection pulse mode; however, they can be also applied for the transmitting (continuous-wave) mode, as shown in an example. Pressure distributions were computed for the acoustic field of the microscope for the first and higher harmonics. Hence, at the frequency of 1 GHz, the effective focal radius in water measured as the −6-dB amplitude pressure drop was found to be 1,1 μm, and 0.7 μm for the second harmonic, independently of the assumed transducer power. So the width of the beam, scanning the living cells in the focal region, was equal to 2.2 μm at the fundamental frequency of 1 GHz.

Keywords:

Temperature, Acoustic microscopy, Living cells, Temperature increase, Pressure

Affiliations:
Kujawska T.-IPPT PAN
Wójcik J.-IPPT PAN
Filipczyński L.-IPPT PAN
4.Filipczyński L., Wójcik J., Kujawska T., Łypacewicz G., Tymkiewicz R., Zienkiewicz B., Nonlinear Native Propagation Effect of Diagnostic Ultrasound Computed and Measured in Blood, ULTRASOUND IN MEDICINE AND BIOLOGY, ISSN: 0301-5629, DOI: 10.1016/S0301-5629(00)00329-X, Vol.27, No.2, pp.251-257, 2001
Abstract:

Nonlinear propagation effects produced by focused pulses in blood were measured over a 20-cm range, being inspired by diagnostic applications in cardiology. The initial and maximum pressures applied during measurements in blood were equal to 0.40 MPapp and 0.76 MPapp, while the pressure estimated at the patient body surface equalled 0.70 MPapp. Measurements of the frequency characteristic and the linearity of the ultrasonic probe used in experiments were performed in water. A numerical procedure developed previously was applied in blood to calculate the pressure distribution of its first and second harmonics along the beam axis. The comparison of numerical and measured distributions in blood at a temperature of 37°C showed rather good agreement. Using numerical methods, a proportional growth of the second harmonic with the increased applied initial pressure was first observed, and finally the maximum limiting effect was found. In this way, much higher level of harmonics could be obtained. However, there arise the questions of the transmitting system construction and of the nonuniform resolution in the case of harmonic imaging when increasing the applied initial pressure.

Keywords:

Ultrasound, Pulses, Nonlinear propagation, Blood, Cardiology

Affiliations:
Filipczyński L.-IPPT PAN
Wójcik J.-IPPT PAN
Kujawska T.-IPPT PAN
Łypacewicz G.-other affiliation
Tymkiewicz R.-IPPT PAN
Zienkiewicz B.-IPPT PAN
5.Filipczyński L., Kujawska T., Tymkiewicz R., Wójcik J., Nonlinear and linear propagation of diagnostic ultrasound pulses, ULTRASOUND IN MEDICINE AND BIOLOGY, ISSN: 0301-5629, DOI: 10.1016/S0301-5629(98)00174-4, Vol.25, No.2, pp.285-299, 1999
Abstract:

The effect of nonlinear propagation in fluid followed by soft tissue was studied both theoretically and experimentally for a most crucial case in obstetrical ultrasonography. For this purpose, short pressure pulses, with the duration time of 1.3 μs and a carrier frequency of 3 MHz, radiated by a concave transducer into water, with maximum intensities up to the value of 18 W/cm2, were computed and measured. The ultrasonic beam had the physical focus at the distance of 6.5 cm, where the highest focal intensity of ISPPA= 242 W/cm2 was obtained. In front of the transducer, at a distance of 7 cm, artificial tissue samples prepared on the basis of ground porcine kidney, with a thickness of 0.5, 1.5 and 3 cm, were placed in water. Pressure pulses and their spectral components were produced numerically and measured by means of a PVDF hydrophone in water before and after penetrating the tissue samples. The theoretical analysis and measurements were carried out, in every case, for two signal levels: for a high level assuring nonlinear propagation and for a low one where conditions of linear propagation were fulfilled. In this way, it was possible to compare directly the effects of nonlinear and linear propagation, in every case showing a good conformity of theoretical values with measured ones. A method of determination of the effective frequency response of the hydrophone was elaborated to enable quantitative comparisons of numerical and experimental results. The theoretical part of our study was based on a paper of Wójcik (1998), enabling us to compute the characteristic function of nonlinear increase of absorption. An agreement of up to 10% was obtained when comparing theoretical and measured values of these functions in the investigated beam in water and behind tissue samples. The results obtained showed that the recently given theory of nonlinear absorption, based on the spectral analysis and the elaborated numerical procedures, may be useful in various practical ultrasonic medical problems and also in technological applications.

Keywords:

Ultrasound, Pulses, Nonlinear propagation, Diagnostics

Affiliations:
Filipczyński L.-IPPT PAN
Kujawska T.-IPPT PAN
Tymkiewicz R.-IPPT PAN
Wójcik J.-IPPT PAN
6.Filipczyński L., Kujawska T., Tymkiewicz R., Wójcik J., Amplitude, isobar and gray -scale imaging of ultrasonic shadows behind rigid, elastic and gaseous spheres, ULTRASOUND IN MEDICINE AND BIOLOGY, ISSN: 0301-5629, DOI: 10.1016/0301-5629(95)02031-4, Vol.22, No.2, pp.261-270, 1996
Abstract:

The theory of wave reflection from spherical obstacles was applied for determination of the cause of the shadow created by plane wave pulses incident on rigid, steel, gaseous spheres and on spheres made of kidney stones. The spheres were immersed in water which was assumed to be a tissuelike medium. Acoustic pressure distributions behind the spheres with the radii of 1 mm, 2.5 mm and 3.5 mm were determined at the frequency of 5 MHz. The use of the exact wave theory enabled us to take into account the diffraction effects. The computed pressure distributions were verified experimentally at the frequency of 5 MHz for a steel sphere with a 2.5-mm radius. The experimental and theoretical pulses were composed of about three ultrasonic frequency periods. Acoustic pressure distributions in the shadow zone of all spheres were shown in the amplitude axonometric projection, in the grey scale and also as acoustic isobar patterns. Our analysis confirmed existing simpler descriptions of the shadow from the point of view of reflection and refraction effects; however, our approach is more general, also including diffraction effects and assuming the pulse mode. The analysis has shown that gaseous spherical inclusions caused shadows with very high dynamics of acoustic pressures that were about 15 dB higher in relation to all the other spheres. The shadow length, determined as the length at which one observes a 6-dB drop of the acoustic pressure, followed the relation r−6dB = 3.7a2λ with the accuracy of about 20% independent of the sphere type. λ denotes the wavelength and a the sphere radius. Thus, a theoretical possibility of differentiating between gaseous and other inclusions and of estimation of the inclusion size in the millimeter range from the shadow was shown. The influence of the frequency-dependent attenuation on the shadow will be considered in the next study.

Keywords:

Shadow, Pulses, Spheres, Ultrasonography

Affiliations:
Filipczyński L.-IPPT PAN
Kujawska T.-IPPT PAN
Tymkiewicz R.-IPPT PAN
Wójcik J.-IPPT PAN
7.Filipczyński L., Kujawska T., Wójcik J., Temperature elevation in focused Gaussian ultrasonic beams at various insonation times, ULTRASOUND IN MEDICINE AND BIOLOGY, ISSN: 0301-5629, DOI: 10.1016/0301-5629(93)90073-W, Vol.19, No.8, pp.667-679, 1993
Abstract:

Transient solution of the thermal conductivity equation for the three-dimensional case of the Gaussian ultrasonic focused beam was derived and applied for cases relevant to medical ultrasonography. Quantitative results for the case of a homogeneous medium with constant values of thermal coefficients and constant absorption as well as for the two-layer tissue model used in obstetrics were presented for various diagnostic probes used in ultrasonography. The possible effects of perfusion and nonlinear propagation were neglected. The results obtained are in agreement with results of other authors when considering the steady-state and the infinitely short insonation time. The computations show the influence of the insonation time on the temperature elevation, thus making it possible to introduce its value as a factor in limiting the possible harmful effects in ultrasonography. This has been shown in diagrams presenting the temperature distribution along the beam axis of 6 different diagnostic probes for various insonation times and demonstrating the corresponding temperature decrease when limiting the insonation time to 5 and 1 min. For instance, the highest temperature elevation (for probe number 1, see Table 1) decreases 2.6 and 5 times with respect to the steady-state temperature when the insonation time equals 5 and 1 min, respectively.

Keywords:

Temperature, Ultrasonography, Time, Hazard

Affiliations:
Filipczyński L.-IPPT PAN
Kujawska T.-IPPT PAN
Wójcik J.-IPPT PAN
8.Filipczyński L., Wójcik J., Estimation of transient temperature elevation in lithotripsy and in ultrasonography, ULTRASOUND IN MEDICINE AND BIOLOGY, ISSN: 0301-5629, DOI: 10.1016/0301-5629(91)90104-5, Vol.17, No.7, pp.715-721, 1991
Abstract:

Transient solutions of the thermal conductivity equation for the two-dimensional case of an elongated cylíndrical focus in the ultrasonic beam were derived and applied for lithotripsy and obstetrical ultrasonography. Assuming uniform and Gaussian distributions in the focus of the beam cross section, it was possible to estimate the temperature elevation arising in lithotripsy for various repetition frequencies of shock-wave pulses and for various radii of the beam. In obstetrical ultrasonography where the blood perfusion is difficult to determine, the authors suggested that the insonation time be used as the decisive factor for the temperature determination. Values of focal intensities were found necessary to increase the tissue temperature by 1°C as a function of the insonation time and the beam radius which exclude the possibility of any hazardous effect caused by temperature elevation.

Keywords:

Lithotripsy, Obstetrics, Ultrasonography, Temperature, Hazard

Affiliations:
Filipczyński L.-IPPT PAN
Wójcik J.-IPPT PAN
9.Filipczyński L., Efekt termiczny w tkankach miękkich powstający pod wpływem zogniskowanych pól ultradźwiękowych o krótkich czasach trwania, Prace IPPT - IFTR Reports, ISSN: 2299-3657, No.72, pp.1-19, 1975
10.Filipczyński L., Stany nieustalone, układ zastępczy i ujemna pojemność piezoelektrycznego przetwornika o drganiach grubościowych, Prace IPPT - IFTR Reports, ISSN: 2299-3657, No.68, pp.1-28, 1974
11.Filipczyński L., Toczyski Z., Bezkontaktowa metoda pomiaru mocy w falowodzie ultradźwiękowym w czasie rzeczywistym, Prace IPPT - IFTR Reports, ISSN: 2299-3657, No.70, pp.1-30, 1974
12.Borodziński K., Filipczyński L., Nowicki A., Powałowski T., Badania prędkości przepływu ultradźwiękową metodą wykorzystującą zjawisko Dopplera, Prace IPPT - IFTR Reports, ISSN: 2299-3657, No.40, pp.1-16, 1972
13.Filipczyński L., Nowicki A., Powałowski T., Kretowicz J., Starzyńska J., Badanie wpływu ultradźwięków promieniowanych przez detektor tętna na chromosomy człowieka w hodowli limfocytów, Prace IPPT - IFTR Reports, ISSN: 2299-3657, No.46, pp.1-24, 1972
14.Filipczyński L., Dosage Problem, Acoustic Output and Sensitivity of Ultrasonic Diagnostic Methods, Prace IPPT - IFTR Reports, ISSN: 2299-3657, No.17, pp.1-10, 1971
15.Filipczyński L., Etienne J., Sferyczne przetworniki ogniskujące o gaussowskim powierzchniowym rozkładzie prędkości, Prace IPPT - IFTR Reports, ISSN: 2299-3657, No.50, pp.1-34, 1971
16.Etienne J., Filipczyński L., Nowicki A., Powałowski T., Ultradźwiękowa metoda badania tętna na zasadzie zjawiska Dopplera, Prace IPPT - IFTR Reports, ISSN: 2299-3657, No.51, pp.1-17, 1970
17.Etienne J., Filipczyński L., Ilmurzyńska K., Sałkowski J., Ultradźwiękowe metody badania czynności serca, Prace IPPT - IFTR Reports, ISSN: 2299-3657, No.5, pp.1-19, 1969
18.Filipczyński L., The Near Field Distribution on the Axis of a Vibrating Piston, Prace IPPT - IFTR Reports, ISSN: 2299-3657, No.11, pp.1-6, 1968

Patents
Numer/data zgłoszenia patentowego
Ogłoszenie o zgłoszeniu patentowym
Twórca / twórcy
Tytuł
Kraj i Nazwa uprawnionego z patentu
Numer patentu
Ogłoszenie o udzieleniu patentu
pdf
239097
1982-11-18
-
1986-11-15
Filipczyński L., Karłowicz P., Nowicki A.
Sposób i urządzenie do rozpoznania zaburzenia przepływu cieczy, zwłaszcza krwi
PL, Instytut Podstawowych Problemów Techniki PAN
136932
-
1984-12-03
206955
1978-05-20
-
1983-03-15
Etienne J., Filipczyński L., Nowicki A., Powałowski T.
Ultradźwiękowe urządzenie dopplerowskie zwłaszcza do pomiaru przepływu krwi
PL, Instytut Podstawowych Problemów Techniki PAN
117416
-
1980-01-28
196471
1977-03-07
-
1979-08-30
Filipczyński L., Nowicki A.
Sposób oraz urządzenie do wizualizacji naczynia krwionośnego i wyznaczania kąta nachylenia wiązki ultradźwiękowej względem naczynia krwionośnego
PL, Instytut Podstawowych Problemów Techniki PAN
103608
-
1978-01-16
179156
1975-03-28
-
1976-10-23
Filipczyński L., Nowicki A., Borodziński K.
Impulsowy ultradźwiękowy miernik przepływu i profilu prędkości cieczy zwłaszcza krwi płynącej w naczyniach krwionośnych
PL, Instytut Podstawowych Problemów Techniki PAN
99449
-
1978-11-15