Institute of Fundamental Technological Research
Polish Academy of Sciences

Staff

Łukasz Fura, PhD

Department of Ultrasound (ZU)
Division of Acoustic Microscopy (PMAk)
position: research specialist
telephone: (+48) 22 826 12 81 ext.: 314
room: 522
e-mail:
ORCID: 0000-0003-4970-7261

Doctoral thesis
2022-09-29 Numeryczna i eksperymentalna optymalizacja planowania leczenia litych nowotworów techniką ablacyjną HIFU kontrolowaną obrazowaniem usg w badaniach przedklinicznych 
supervisor -- Tamara Kujawska, PhD, DSc, IPPT PAN
supervisor -- Prof. Dr. Norbert Żołek, IPPT PAN
 

Recent publications
1.  Fura Ł., Dera W., Dziekoński C., Świątkiewicz M., Kujawska T., Experimental evaluation of targeting accuracy of ultrasound imaging-guided robotic HIFU ablative system for the treatment of solid tumors in pre-clinical studies, APPLIED ACOUSTICS, ISSN: 0003-682X, DOI: 10.1016/j.apacoust.2021.108367, Vol.184, pp.108367-1-9, 2021

Abstract:
We have designed and built low-cost compact ultrasound imaging-guided robotic HIFU (High-Intensity Focused Ultrasound) ablation device for thermal damage of solid tumors in small animals. Before this device is used to treat animals, experimental studies on ex vivo tissues were necessary to assess the accuracy of its targeting, ensuring the safety of therapy. The objective of this study was to assess the targeting accuracy of our device in the focal and axial plane of the HIFU beam using ex vivo tissue embedded in a reference cylindrical chamber inside which a coaxial cylindrical volume with a smaller diameter was ablated. HIFU beams with selected acoustic parameters, generated by a singe-element bowl-shaped 64-mm HIFU transducer operating at 1.08 MHz or 3.21 MHz frequency, were propagated in two-layer media: water-tissue (50 mm-40 mm) and focused at 12.6-mm depth below the tissue surface. Cylindrical necrotic lesions of various size were created by moving the chamber using a computercontrolled precise positioning unit. Lesions formed were compared with those intended for treatment using various visualization methods and displacement between their centers were determined. The targeting accuracy in the focal and axial planes was found to be respectively about 98% and 86% when determined from photos and about 88% and 76% when determined from MR images. The displacement between the centers of the necrotic lesion formed and planned for treatment was about 1 mm in the focal plane and about 2 mm in the axial plane. Our ablation device can be used as an effective and safe tool to plan, monitor and treat solid tumors in small animals and to test new anti-cancer drugs in preclinical studies.

Affiliations:
Fura Ł. - IPPT PAN
Dera W. - IPPT PAN
Dziekoński C. - IPPT PAN
Świątkiewicz M. - Mossakowski Medical Research Centre, Polish Academy of Sciences (PL)
Kujawska T. - IPPT PAN
2.  Fura Ł., Dera W., Dziekoński C., Świątkiewicz M., Kujawska T., Experimental assessment of the impact of sonication parameters on necrotic lesions induced in tissues by HIFU ablative device for preclinical studies, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.24425/aoa.2021.136573, Vol.46, No.2, pp.341-352, 2021

Abstract:
We have designed and built ultrasound imaging-guided HIFU ablative device for preclinical studies on small animals. Before this device is used to treat animals, ex vivo tissue studies were necessary to determine the location and extent of necrotic lesions created inside tissue samples by HIFU beams depending on their acoustic properties. This will allow to plan the beam movement trajectory and the distance and time intervals between exposures leading to necrosis covering the entire treated volume without damaging the surrounding tissues. This is crucial for therapy safety. The objective of this study was to assess the impact of sonication parameters on the size of necrotic lesions formed by HIFU beams generated by 64-mm bowl-shaped transducer used, operating at 1.08 MHz or 3.21 MHz. Multiple necrotic lesions were created in pork loin samples at 12.6-mm depth below tissue surface during 3-s exposure to HIFU beams with fixed duty-cycle and varied pulse-duration or fixed pulse-duration and varied duty-cycle, propagated in two-layer media: water-tissue. After exposures, the necrotic lesions were visualized using magnetic resonance imaging and optical imaging (photos) after sectioning the samples. Quantitative analysis of the obtained results allowed to select the optimal sonication and beam movement parameters to suport planning of effective therapy.

Keywords:
automated ultrasound imaging-guided HIFU ablation system, ex vivo tissue, ultrasonic exposure parameters, extent of necrotic lesions

Affiliations:
Fura Ł. - IPPT PAN
Dera W. - IPPT PAN
Dziekoński C. - IPPT PAN
Świątkiewicz M. - Mossakowski Medical Research Centre, Polish Academy of Sciences (PL)
Kujawska T. - IPPT PAN
3.  Fura Ł., Kujawska T., Selection of exposure parameters for a HIFU ablation system using an array of thermocouples and numerical simulations, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.24425/aoa.2019.128498, Vol.44, No.2, pp.349-355, 2019

Abstract:
Image-guided High Intensity Focused Ultrasound (HIFU) technique is dynamically developing technology for treating solid tumors due to its non-invasive nature. Before a HIFU ablation system is ready for use, the exposure parameters of the HIFU beam capable of destroying the treated tissue without damaging the surrounding tissues should be selected to ensure the safety of therapy. The purpose of this work was to select the threshold acoustic power as well as the step and rate of movement of the HIFU beam, generated by a transducer intended to be used in the HIFU ablation system being developed, by using an array of thermocouples and numerical simulations. For experiments a bowl-shaped 64-mm, 1.05 MHz HIFU transducer with a 62.6 mm focal length (f-number 0.98) generated pulsed waves propagating in two-layer media: water/ex vivo pork loin tissue (50 mm/40 mm) was used. To determine a threshold power of the HIFU beam capable of creating the necrotic lesion in a small volume within the tested tissue during less than 3 s each tissue sample was sonicated by multiple parallel HIFU beams of different acoustic power focused at a depth of 12.6 mm below the tissue surface. Location of the maximum heating as well as the relaxation time of the tested tissue were determined from temperature variations recorded during and after sonication by five thermo-couples placed along the acoustic axis of each HIFU beam as well as from numerical simulations. The obtained results enabled to assess the location of each necrotic lesion as well as to determine the step and rate of the HIFU beam movement. The location and extent of the necrotic lesions created was verified using ultrasound images of tissue after sonication and visual inspection after cutting the samples. The threshold acoustic power of the HIFU beam capable of creating the local necrotic lesion in the tested tissue within 3 s without damaging of surrounding tissues was found to be 24 W, and the pause between sonications was found to be more than 40 s.

Keywords:
automated HIFU ablation system, threshold acoustic power of HIFU beam, ex vivo tissue, necrotic lesion, thermocouple array

Affiliations:
Fura Ł. - IPPT PAN
Kujawska T. - IPPT PAN

Conference papers
1.  Fura Ł., Żołek N., Kujawska T., Numerical simulations and experimental verification of the extent of HIFU-induced tissue necrosis, SPIE Medical Imaging, 2022, 2022-02-20/02-24, San Diego (US), DOI: 10.1117/12.2608140, No.12034, pp.1-5, 2022

Abstract:
Local ultrasonic tissue ablation is induced by a rapid (<3s) rise in temperature in a small ellipsoidal volume (about 13mm3) inside the tissue to a cytotoxic level when exposed to a high-intensity focused ultrasound (HIFU) beam. The aim of this study was to develop a numerical tool to predict the location and extent of a necrotic lesion formed locally inside the ex vivo tissue as a result of exposure to a single or multiple HIFU beam, ensuring the efficacy and safety of destroying solid tumors. The proposed tool was based on modelling the non-linear propagation of acoustic waves and heat transfer in heterogeneous media using the k-wave toolbox. The wave propagation equations were solved for two-layer (water/tissue) media. The source of the acoustic waves was a spherical bowl-shaped transducer with a resonance frequency of 1.08 MHz. The distribution of heat sources was determined from the calculated acoustic pressure distribution in the HIFU beam. The obtained temperature distributions during heating and cooling allowed calculation of the thermal dose and prediction of the extent of the necrotic lesion. The obtained results of numerical simulations were compared with the experimental data from previous studies. The mean difference between the calculated and measured length or diameter of a single exposure induced necrotic lesion was approximately 1 mm. In the case of a necrotic lesion induced by multiple exposures, the mean difference between the measured and calculated cross-sectional area of the planned necrotic lesion covered with necrosis was approximately 11.2 %.

Keywords:
HIFU, modelling, numerical simulations, treatment planning, ex vivo experiments, necrotic lesions, thermal ablation, experimental verification

Affiliations:
Fura Ł. - IPPT PAN
Żołek N. - IPPT PAN
Kujawska T. - IPPT PAN

Conference abstracts
1.  Fura Ł., Żołek N., Kujawska T., Numerical simulations and experimental verification of the extent of HIFU-induced necrotic lesions, ISTU 2022, The 21st Annual International Symposium on Therapeutic Ultrasound, 2022-06-07/06-10, University of Toronto (CA), pp.1, 2022
2.  Fura Ł., Żołek N., Kujawska T., Numerical simulations of the ultrasonic tissue ablation process, XXII Polish Conference on Biocybernetics and Biomedical Engineering, 2021-05-19/05-21, Warszawa (PL), pp.1, 2021
3.  Fura Ł., Dera W., Dziekoński C., Kujawska T., Evaluation of influence of ultrasound exposure parameters on necrotic lesions induced in tissues by robotic ultrasound-guided HIFU ablation device, 2019 ICU Bruges, 2019 International Congress on Ultrasonics, 2019-09-03/09-06, Bruges (BE), pp.1, 2019
4.  Fura Ł., Dera W., Dziekoński C., Kujawska T., Experimental evaluation of the accuracy of targeting of a robotic ultrasound imaging-guided hifu ablation device for treating solid tumors in small animals, ISTU 2019, The 19th International Symposium for Therapeutic Ultrasound, 2019-06-13/06-15, Barcelona (ES), pp.1, 2019
5.  Fura Ł., Dera W., Dziekoński C., Kujawska T., Evaluation of targeting accuracy of a robotic ultrasound imaging-guided HIFU ablation device for treating solid tumors in small animals, 2019 ICU Bruges, 2019 International Congress on Ultrasonics, 2019-09-03/09-06, Bruges (BE), pp.1, 2019
6.  Fura Ł., Dera W., Dziekoński C., Kujawska T., Experimental evaluation of the impact of ultrasound exposure parameters on necrotic lesions induced in tissue by a robotic ultrasound-guided hifu ablation device for treating solid tumors in small animals, ISTU 2019, The 19th International Symposium for Therapeutic Ultrasound, 2019-06-13/06-15, Barcelona (ES), pp.1, 2019

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