Статті в журналах: "HIFU transducer"

1

Shin, Eui-Ji, Byungwoo Kang, and Jin Chang. "Real-Time HIFU Treatment Monitoring Using Pulse Inversion Ultrasonic Imaging." Applied Sciences 8, no. 11 (November 11, 2018): 2219. http://dx.doi.org/10.3390/app8112219.

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Real-time monitoring of high-intensity focused ultrasound (HIFU) surgery is essential for safe and accurate treatment. However, ultrasound imaging is difficult to use for treatment monitoring during HIFU surgery because of the high intensity of the HIFU echoes that are received by an imaging transducer. Here, we propose a real-time HIFU treatment monitoring method based on pulse inversion of imaging ultrasound; an imaging transducer fires ultrasound twice in 0° and 180° phases for one scanline while HIFUs of the same phase are transmitted in synchronization with the ultrasound transmission for imaging. By doing so, HIFU interferences can be eliminated after subtracting the two sets of the signals received by the imaging transducer. This function was implemented in a commercial research ultrasound scanner, and its performance was evaluated using the excised bovine liver. The experimental results demonstrated that the proposed method allowed ultrasound images to clearly show the echogenicity change induced by HIFU in the excised bovine liver. Additionally, it was confirmed that the moving velocity of the organs in the abdomen due to respiration does not affect the performance of the proposed method. Based on the experimental results, we believe that the proposed method can be used for real-time HIFU surgery monitoring that is a pivotal function for maximized treatment efficacy.

2

Liu, Li, and Jian Sun. "A Study of High Intensity Focusing Ultrasonic Transducer." Applied Mechanics and Materials 201-202 (October 2012): 20–23. http://dx.doi.org/10.4028/www.scientific.net/amm.201-202.20.

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High intensity focused ultrasound (HIFU) is the fourth brand-new and efficient means to cure tumour acknowledged by the medical field. Study of ultrasonic transducer is a core part of HIFU technique, In order to ensure reliability and safety of treatment, it is a key for HIFU technique to realize accurate focusing of ultrasonic energy. In the thesis, ultrasonic focusing method, studies of current situations of cell and multiplex array focusing transducers and their existing problems are illustrated based on analyzing challenges faced by HIFU treatment at present. This study suggested that phased array was theoretically easy for realizing accurate control of computer， however, unbeneficial factors and engineering technical problems still exist; How to promote intensity of the focal spot of cell array focusing transducer, enlarge scope of the focal area and improve control way of the focal spot was a bottleneck problem for publicizing and applying cell array focusing transducer and one of urgent research topics for ensuring curative effect of HIFU and avoiding heat damages.

3

Shan, Feng, Xiasheng Guo, Juan Tu, Jianchun Cheng, and Dong Zhang. "Multi-relaxation-time lattice Boltzmann modeling of the acoustic field generated by focused transducer." International Journal of Modern Physics C 28, no. 03 (March 2017): 1750038. http://dx.doi.org/10.1142/s0129183117500383.

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The high-intensity focused ultrasound (HIFU) has become an attractive therapeutic tool for the noninvasive tumor treatment. The ultrasonic transducer is the key component in HIFU treatment to generate the HIFU energy. The dimension of focal region generated by the transducer is closely relevant to the safety of HIFU treatment. Therefore, it is essential to numerically investigate the focal region of the transducer. Although the conventional acoustic wave equations have been used successfully to describe the acoustic field, there still exist some inherent drawbacks. In this work, we presented an axisymmetric isothermal multi-relaxation-time lattice Boltzmann method (MRT-LBM) model with the Bouzidi–Firdaouss–Lallemand (BFL) boundary condition in cylindrical coordinate system. With this model, some preliminary simulations were firstly conducted to determine a reasonable value of the relaxation parameter. Then, the validity of the model was examined by comparing the results obtained with the LBM results with the Khokhlov–Zabolotskaya–Kuznetsov (KZK) equation and the Spheroidal beam equation (SBE) for the focused transducers with different aperture angles, respectively. In addition, the influences of the aperture angle on the focal region were investigated. The proposed model in this work will provide significant references for the parameter optimization of the focused transducer for applications in the HIFU treatment or other fields, and provide new insights into the conventional acoustic numerical simulations.

4

Bui, Ngoc Thang, Thi My Tien Nguyen, Gebremedhin Yonatan Ataklti, Quoc Cuong Bui, Tran Thanh Nam Dinh, Duc Tri Phan, Sumin Park, Jaeyeop Choi, Thi Thu Ha Vu, and Junghwan Oh. "Design of a High-Power Multilevel Sinusoidal Signal and High-Frequency Excitation Module Based on FPGA for HIFU Systems." Electronics 10, no. 11 (May 29, 2021): 1299. http://dx.doi.org/10.3390/electronics10111299.

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High-intensity focused ultrasound (HIFU) is a noninvasive therapy that uses focused ultrasound to treat a part of the tissue; high temperatures can damage tissues by heat. HIFU has many applications in the field of surgery and aesthetics and is used increasingly in everyday life. In this article, we discuss the mainboard design that controls the HIFU system with the ability to create a multistep sine wave compatible with many different applications. The signal used to trigger the transducer is a sinusoidal signal with a frequency adjustable from 0.1 to 3 MHz. In addition, the power supplied to the HIFU transducer is also controlled easily by the configuration parameters installed in the control circuit board. The proposed control and design method generates a voltage signal that doubles the supply voltage, thereby reducing the current on the MOSFET. The hardware design is optimized for a surface-mounted device-type MOSFET without the need for an external heat sink. In tests, we conducted a harmonious combination of two output signals to activate the same HIFU probe. The results showed that the energy transferred to the HIFU transducer increased by 1.5 times compared to a single channel. This means that the HIFU treatment time is reduced when using this method, with absolutely no changes in the system structure.

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Cato, Sharon, Florent Aptel, Philippe Denis, Gail ter Haar, Shlomo Melamed, Eric Sellem, Tarek Shaarawy, and David Wright. "Ultrasound Circular Cyclo-Coagulation – Innovation in Glaucoma with High Intensity Focused Ultrasound." European Ophthalmic Review 05, no. 02 (2011): 109. http://dx.doi.org/10.17925/eor.2011.05.02.109.

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Existing treatment modalities for glaucoma, including pharmacological therapy, lasers, surgery and shunts, are all associated with shortcomings. Ultrasonic coagulation of the ciliary body with pinpoint precision using high intensity focused ultrasound (HIFU) enables significant reduction of aqueous inflow and intraocular pressure (IOP). Energy is focused through non-optically transparent media with controlled energy absorption, reducing effects on adjacent tissues. Energy deposition and tissue heating at the focus site do not depend on tissue pigmentation, thus improving predictability. Currently, high-frequency miniaturised transducers create small focal zones for improved treatment area targeting, and ultrasound focusing provides enhanced control. The high operating frequency allows a sharp transition between the focal zone and the untreated area, reducing risks of heating adjacent healthy tissue. Such transducers are used extensively in malignant tumour treatments. Novel Ultrasound Circular Cyclo-Coagulation (UC3) with a miniaturised annular transducer uses HIFU technology. The circular geometry of the device allows precise, constant and reproducible positioning. Results from animal studies and from a clinical pilot study of patients with refractory glaucoma indicate that ultrasonic coagulation of the ciliary body using HIFU delivered by a circular miniaturised transducer is an effective and well-tolerated method of reducing IOP. The single-step procedure is short, easy to perform and accurate. Glaucoma impacts patients’ quality of life, including unpleasant treatment side effects and social and physical aspects. Gold-standard trabeculectomy shortcomings highlight the need for precise, focused surgical modalities. HIFU is a non-invasive, cost-effective innovation that, should the multicentre clinical trial demonstrate similar results to the preclinical and pilot studies, will be a useful addition to current glaucoma management techniques.

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Seo, Hyunkwan, Sung Kwan Hwang, Hee-Won Kim, and Kyu Chan Lee. "Motion Accuracy of Pneumatic Stepper Motor-Driven Robotic System Developed for MRI-Guided High-Intensity Focused Ultrasound Treatment of Prostate Disease." Applied Bionics and Biomechanics 2024 (May 10, 2024): 1–13. http://dx.doi.org/10.1155/2024/5556537.

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The latest advancement in high-intensity focused ultrasound (HIFU) treatment technology integrates magnetic resonance imaging (MRI) guidance for precise treatment of prostate disease. As conventional electromagnetic motors are not applicable for utilization within MRI scanners, we have developed a prototype robotic system driven by pneumatic stepper motors to control the movement of the HIFU transducer within an intrarectal probe during MRI-guided HIFU treatment procedures. These pneumatic stepper motors were constructed entirely from MRI-compatible plastic materials. Assessment of the robotic system’s MRI compatibility was conducted utilizing a 3.0T MRI scanner, revealing no discernible MRI image distortion with a minor decrease in the signal-to-noise ratio (2.8%) during the motor operation. The robotic system enabled the transducer to move inside the probe with two degrees of freedom, allowing both linear and rotational motion. The positional accuracy of the transducer movement was assessed, yielding ±0.20 and ±0.22 mm accuracies in the forward and backward linear movements, respectively, and ±0.79° and ±0.74° accuracies in the clockwise and counterclockwise rotational motions, respectively. Emulation of authentic HIFU procedures involved creating a two-dimensional array of thermal lesions in a tissue-mimicking phantom, achieving positional accuracy within ±1 mm for the generated HIFU focal spots. The prototype robotic system incorporating pneumatic stepper motors fabricated entirely from MRI-compatible plastic materials has demonstrated the requisite positional accuracy necessary for effective HIFU treatment of prostate disease, indicating substantial promise for future clinical application.

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Lim, Hae Gyun, Hyunhee Kim, Kyungmin Kim, Jeongwoo Park, Yeonggeun Kim, Jinhee Yoo, Dasom Heo, Jinhwan Baik, Sung-Min Park, and Hyung Ham Kim. "Thermal Ablation and High-Resolution Imaging Using a Back-to-Back (BTB) Dual-Mode Ultrasonic Transducer: In Vivo Results." Sensors 21, no. 5 (February 24, 2021): 1580. http://dx.doi.org/10.3390/s21051580.

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We present a back-to-back (BTB) structured, dual-mode ultrasonic device that incorporates a single-element 5.3 MHz transducer for high-intensity focused ultrasound (HIFU) treatment and a single-element 20.0 MHz transducer for high-resolution ultrasound imaging. Ultrasound image-guided surgical systems have been developed for lesion monitoring to ensure that ultrasonic treatment is correctly administered at the right locations. In this study, we developed a dual-element transducer composed of two elements that share the same housing but work independently with a BTB structure, enabling a mode change between therapy and imaging via 180-degree mechanical rotation. The optic fibers were embedded in the HIFU focal region of ex vivo chicken breasts and the temperature change was measured. Images were obtained in vivo mice before and after treatment and compared to identify the treated region. We successfully acquired B-mode and C-scan images that display the hyperechoic region indicating coagulation necrosis in the HIFU-treated volume up to a depth of 10 mm. The compact BTB dual-mode ultrasonic transducer may be used for subcutaneous thermal ablation and monitoring, minimally invasive surgery, and other clinical applications, all with ultrasound only.

8

Qian, Jun, Wei Xie, Xiao-Wei Zhou, Jian-Wen Tan, Zhi-Biao Wang, Yong-Hong Du, and Yan-Hao Li. "Real-time monitoring of high intensity focused ultrasound focal damage based on transducer driving signal." Acta Physica Sinica 71, no. 3 (2022): 037201. http://dx.doi.org/10.7498/aps.71.20211443.

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Real-time monitoring of high intensity focused ultrasound (HIFU) focal region is a key problem in clinical treatment of focused ultrasound. At present, the change of strong echo in B-ultrasound image is often used in clinical practice to monitor tissue damage in the focal area. However, the strong echo in B-ultrasound image is mostly related to cavitation and boiling bubbles in the focal area, which cannot monitor the treatment status accurately or in real time. In the HIFU treatment, the focal area tissue will be accompanied by changes in temperature, cavitation, boiling, and tissue characteristics. The acoustic load on the surface of the transducer is also constantly changing. To solve this problem, a real-time detection platform of transducer voltage and current is built in this work, which can sense the change of focal area tissue state by measuring the electrical parameters of the transducer. The experimental results show that the stability of the phase difference of the transducer driving signal will be different (the fluctuation amplitude will be different) when different media are placed on the surface of the transducer to change the acoustic load on the surface of the transducer. The fluctuation amplitude of the phase difference of the driving signal will be larger than that in the water when the iron plate is placed in the focal plane. However, the phase fluctuation amplitude will be much smaller than that in the water where the beef liver is placed. This shows that different acoustic loads can cause the electrical parameters of the transducer to change. The isolated bovine liver tissue is used as the HIFU irradiation object, and the results of the phase difference change are compared with the results of the isolated bovine liver tissue damage. The experimental results show that the phase of the transducer voltage and current will change from relatively stable to large fluctuations during the HIFU irradiation. At this time, obvious damage can be seen in the focal region when the irradiation is stopped, and the grayscale of B-ultrasound image has no significant change. In addition, when the cavitation occurs in the focal region, the fluctuation amplitude and range will turn larger. The damage area of the lower focal area under the monitoring method is smaller than that under B-ultrasonic monitoring, and the over input of radiation dose can be avoided. This method can provide a new research scheme and means for HIFU focal area tissue damage monitoring.

9

An, Chih Yu, Jia Hao Syu, Ching Shiow Tseng, and Chih-Ju Chang. "An Ultrasound Imaging-Guided Robotic HIFU Ablation Experimental System and Accuracy Evaluations." Applied Bionics and Biomechanics 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/5868695.

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In recent years, noninvasive thermal treatment by using high-intensity focused ultrasound (HIFU) has high potential in tumor treatment. The goal of this research is to develop an ultrasound imaging-guided robotic HIFU ablation system for tumor treatment. The system integrates the technologies of ultrasound image-assisted guidance, robotic positioning control, and HIFU treatment planning. With the assistance of ultrasound image guidance technology, the tumor size and location can be determined from ultrasound images as well as the robotic arm can be controlled to position the HIFU transducer to focus on the target tumor. After the development of the system, several experiments were conducted to measure the positioning accuracy of this system. The results show that the average positioning error is 1.01 mm with a standard deviation 0.34, and HIFU ablation accuracy is 1.32 mm with a standard deviation 0.58, which means this system is confirmed with its possibility and accuracy.

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Kaczkowski, Peter, and Juvenal Ormachea. "The verasonics platform for ultrasound-guided focused ultrasound preclinical studies." Journal of the Acoustical Society of America 153, no. 3_supplement (March 1, 2023): A101. http://dx.doi.org/10.1121/10.0018303.

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Verasonics, in partnership with Sonic Concepts (Bothell, WA, USA), has developed a turnkey platform for Ultrasound-Guided Focused Ultrasound (USgFUS) therapy with performance over a wide range of acoustic regimes. Built around the Verasonics Vantage HIFU ultrasound research system, it uses a 150 mm diameter, f1 HIFU transducer with 64 (0.5 MHz) or 128 (1.1 and 2 MHz) elements arranged in a spiral pattern that produce a highly focused field with low sidelobes over a 3D steering volume. Guidance and monitoring are provided by a coaxially mounted 128-element broadband phased array imaging transducer that can be rotated about the HIFU axis. Coupling to the subject is achieved by means of a membrane sealed water-filled cone through which degassed and temperature regulated water is circulated. The USgFUS applicator is mounted on an articulated arm that can be mechanically locked with a button actuated servo mechanism. Graphical software enables a conventional therapeutic workflow including imaging with any of several B-Mode and Doppler modalities, positioning of the applicator, focal zone exposure planning, therapy delivery, interleaved ultrasound monitoring using any supplied imaging mode or with Thermal Strain Imaging (TSI), and post-therapy imaging. This talk will describe the platform and provide examples of its capabilities using experiments in scattering phantoms and ex vivo tissues.

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Takagi, Ryo, Toshikatsu Washio, and Yoshihiko Koseki. "The feasibility of a noise elimination method using continuous wave response of therapeutic ultrasound signals for ultrasonic monitoring of high-intensity focused ultrasound treatment." Journal of Medical Ultrasonics 48, no. 2 (April 2021): 123–35. http://dx.doi.org/10.1007/s10396-021-01083-5.

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Abstract Purpose In this study, the robustness and feasibility of a noise elimination method using continuous wave response of therapeutic ultrasound signals were investigated when tissue samples were moved to simulate the respiration-induced movements of the different organs during actual high-intensity focused ultrasound (HIFU) treatment. In addition to that, the failure conditions of the proposed algorithm were also investigated. Methods The proposed method was applied to cases where tissue samples were moved along both the lateral and axial directions of the HIFU transducer to simulate respiration-induced motions during HIFU treatment, and the noise reduction level was investigated. In this experiment, the speed of movement was increased from 10 to 40 mm/s to simulate the actual movement of the tissue during HIFU exposure, with the intensity and driving frequency of HIFU set to 1.0–5.0 kW/cm2 and 1.67 MHz, respectively. To investigate the failure conditions of the proposed algorithm, the proposed method was applied with the HIFU focus located at the boundary between the phantom and water to easily cause cavitation bubbles. The intensity of HIFU was set to 10 kW/cm2. Results Almost all HIFU noise was constantly able to be eliminated using the proposed method when the phantom was moved along the lateral and axial directions during HIFU exposure. The noise reduction level (PRL in this study) at an intensity of 1.0, 3.0, and 5.0 kW/cm2 was in the range of 28–32, 38–40, and 42–45 dB, respectively. On the other hand, HIFU noise was not basically eliminated during HIFU exposure after applying the proposed method in the case of cavitation generation at the HIFU focus. Conclusions The proposed method can be applicable even if homogeneous tissues or organs move axially or laterally to the direction of HIFU exposure because of breathing. A condition under which the proposed algorithm failed was when instantaneous tissue changes such as cavitation bubble generation occurred in the tissue, at which time the reflected continuous wave response became less steady.

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LEE, KANG IL, IMBO SIM, GWAN SUK KANG, and MIN JOO CHOI. "NUMERICAL SIMULATION OF TEMPERATURE ELEVATION IN SOFT TISSUE BY HIGH INTENSITY FOCUSED ULTRASOUND." Modern Physics Letters B 22, no. 11 (May 10, 2008): 803–7. http://dx.doi.org/10.1142/s0217984908015413.

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In focused ultrasound surgery, high intensity focused ultrasound (HIFU) can be used to destroy pathological tissue deep inside the body without any damage to the surrounding normal tissue. This noninvasive technique has been used to treat malignant tumors of the liver, prostate, kidney, and benign breast tumors via a percutaneous or transrectal approach without the need for general anaesthesia. In the present study, a finite element method was used for the simulation of temperature elevation in soft tissue by HIFU. First, the HIFU field was modeled using the Westervelt equation for the propagation of finite-amplitude sound in a thermoviscous fluid in order to account for the effects of diffraction, absorption, and nonlinearity. Second, the Pennes bioheat transfer equation was used to predict the temperature elevation in soft tissue by HIFU. In order to verify the numerical simulation, the simulated temperature elevation at the focus in a tissue-mimicking phantom was compared with the measurements, using a concave focused transducer with a focal length of 62.6 mm, a radius of 35.0 mm, and a center frequency of 1.1 MHz.

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Wang, Haoyang, Yuchen Sun, Yuxin Wang, Ying Chen, Yun Ge, Jie Yuan, and Paul Carson. "Temperature-Controlled Hyperthermia with Non-Invasive Temperature Monitoring through Speed of Sound Imaging." Applied Sciences 13, no. 12 (June 20, 2023): 7317. http://dx.doi.org/10.3390/app13127317.

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Hyperthermia therapy (HT) is used to treat diseases through heating of high temperature usually in conjunction with some other medical therapeutics such as chemotherapy and radiotherapy. In this study, we propose a promising temperature-controlled hyperthermia method that uses high-intensity focused ultrasound (HIFU) for clinical tumor treatment combined with diagnostic ultrasound image guidance and non-invasive temperature monitoring through speed of sound (SOS) imaging. HIFU heating is realized by a ring ultrasound transducer array with 256 elements. In this study, tumors in the human thigh were set as heating targets. The inner structure information of thigh tissue is obtained by B-mode ultrasound imaging. Since the relationship between temperature and SOS in different human tissue is available, the temperature detection is converted to the SOS detection obtained by the full-wave inversion (FWI) method. Simulation results show that our model can achieve expected hyperthermia of constant temperature on tumor target with 0.2 °C maximum temperature fluctuation for 5 h. Through simulation, our proposed thermal therapy model achieves accurate temperature control of ±0.2 °C in human thigh tumors, which verifies the feasibility of the proposed temperature-controlled hyperthermia model. Furthermore, the temperature measurement can share the same ring ultrasound transducer array for HIFU heating and B-mode ultrasound imaging, which provides a guiding significance for clinical application.

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Christoffersen, Carlos, Wai Wong, Samuel Pichardo, Greg Togtema, and Laura Curiel. "Class-DE Ultrasound Transducer Driver for HIFU Therapy." IEEE Transactions on Biomedical Circuits and Systems 10, no. 2 (April 2016): 375–82. http://dx.doi.org/10.1109/tbcas.2015.2406119.

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Rongmin, Xia, Shou Wende, Chen Guoping, and Zhang Meidun. "A new-style phased array transducer for HIFU." Applied Acoustics 63, no. 9 (September 2002): 957–64. http://dx.doi.org/10.1016/s0003-682x(02)00013-0.

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Daschner, Rosa, Holger Hewener, Wolfgang Bost, Steffen Weber, Steffen Tretbar, and Marc Fournelle. "Ultrasound Thermometry for HIFU-Therapy." Current Directions in Biomedical Engineering 7, no. 2 (October 1, 2021): 554–57. http://dx.doi.org/10.1515/cdbme-2021-2141.

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Abstract High-Intensity Focused Ultrasound (HIFU) is an alternative tumour therapy with the ability for non-invasive thermal ablation of tissue. For a safe application, the heat deposition needs to be monitored over time, which is currently done with Magnetic Resonance Imaging. Ultrasound (US) based monitoring is a promising alternative, as it is less expensive and allows the use of a single device for both therapy and monitoring. In this work, a method for spatial and temporal US thermometry has been investigated based on simulation studies and in-vitro measurements. The chosen approach is based on the approximately linear dependence between temperature and speed of sound (SoS) in tissue for a given temperature range. By tracking the speckles of successive B-images, the possibility of detecting local changes in SoS and therefore in temperature is given. A speckle tracking algorithm was implemented for 2D and 3D US thermometry using a spatial compounding method to reduce artifacts. The algorithm was experimentally validated in an agar-based phantom and in porcine tissue for temperature rises up to △ 8°C. We used a focusing single element US transducer as therapeutic probe, a linear (/matrix array) transducer with 128 (/32∙32) elements for imaging and thermocouples for validation and calibration. In all experiments, both computational and in-vitro, we succeeded in monitoring the thermal induced SoS changes over time. The in-vitro measurements were in good agreement with the simulation results and the thermocouple measurements (rms temperature difference = 0.53 °C, rms correlation coefficient = 0. 96).

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Jeong, Jong Seob, Jonathan Matthew Cannata, and K. Kirk Shung. "Adaptive HIFU noise cancellation for simultaneous therapy and imaging using an integrated HIFU/imaging transducer." Physics in Medicine and Biology 55, no. 7 (March 12, 2010): 1889–902. http://dx.doi.org/10.1088/0031-9155/55/7/007.

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Azuelos, Arié, Mounia SidAhmed-Mezi, Simone La Padula, Celine Aboud, Jean-Paul Meningaud, and Barbara Hersant. "High-Intensity Focused Ultrasound: A Satisfactory Noninvasive Procedure for Neck Rejuvenation." Aesthetic Surgery Journal 39, no. 8 (March 29, 2019): NP343—NP351. http://dx.doi.org/10.1093/asj/sjz093.

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Abstract Background High-intensity focused ultrasound (HIFU) is an advanced technology that has been developed in response to the growing demand for noninvasive face rejuvenation. Objectives The aim of this study was to evaluate the rejuvenation effects, patient satisfaction, and safety of HIFU treatment of the neck in a European population. Methods This was a prospective study of 20 patients. The patients were treated with HIFU, and the outcomes were investigated. The modified FACE-Objective Assessment Scale, developed by our team, and the subjective Investigator Global Improvement Assessment Scale (IGIAS; –1 to 3) were used to judge the results of HIFU. Five blinded evaluators scored the procedure outcomes based on photographs taken before and 6 months after the procedure. Side effects were reported and pain was evaluated on a visual analog scale of 0 to 10. Results Clinical results, such as better definition of the cervicomental angle, were observed in the treated areas. The pretreatment and posttreatment evaluation scores for double chin and skin laxity were evaluated by 4 of 5 evaluators as significantly improved. The IGIAS score was between 1 and 5 in 2 patients, between 6 and 10 in 7 patients, and between 11 and 15 in 11 patients. No patients had a score between –5 and 0. No major complications were reported. The mean pain scores for the D4, M7, and S7 transducer treatments were 5.6 (range, 4.5–6.7), 4.2 (range, 2.5–5.9), and 2.05 (range, 1.05–3.05), respectively. Conclusions HIFU may be considered a satisfactory, simple, reproducible, rapid, and safe procedure for neck rejuvenation. Level of Evidence: 4

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Thomas, Gilles P., Tatiana D. Khokhlova, Oleg A. Sapozhnikov, and Vera A. Khokhlova. "Extension of boiling histotripsy lesions by axial focus steering during pulse delivery." Journal of the Acoustical Society of America 152, no. 4 (October 2022): A248. http://dx.doi.org/10.1121/10.0016164.

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Boiling histotripsy (BH) is a pulsed high intensity focused ultrasound (HIFU) method relying on the generation of high amplitude shocks and bubble activity to induce tissues liquefaction. A sequence of pulses, 1–20 ms long, generates boiling bubbles at the focus of the HIFU transducer within each pulse, and the remainder of the pulse then interacts with those bubbles. One effect is the creation of a prefocal bubble cloud due to shock scattering: the shock is inverted when reflected from the bubble wall resulting in sufficient negative pressure to reach intrinsic cavitation threshold immediately proximally to these bubbles. Here, a methodology is proposed to extend the length of this prefocal bubble cloud by steering the focus toward the transducer during the BH pulse and thus accelerate treatment. A BH system comprising a 1.5 MHz 256-element phased array connected to a Verasonics V1 system was used. High-speed imaging in transparent gels was performed to observe the extension of the bubble cloud resulting from shock scattering. Volumetric BH lesions were generated in ex vivo tissue. Results showed a threefold increase of the volumetric ablation rate with focus steering compared to standard BH. [Work supported by NIH R01EB007643, R01GM122859, and R01EB25187.]

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Perry, Kaitlyn, Robert Staruch, Samuel Pichardo, Yuexi Huang, Merrylee McGuffin, Ari Partanen, Shun Wong, et al. "Magnetic resonance-guided high intensity focused ultrasound (MR-HIFU) hyperthermia for primary rectal cancer: A virtual feasibility analysis." Journal of Global Oncology 5, suppl (October 7, 2019): 77. http://dx.doi.org/10.1200/jgo.2019.5.suppl.77.

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77 Background: MR-HIFU Hyperthermia (HT) is a non-invasive treatment modality with real-time thermometry that ensures accurate and precise heating of a target with minimal effect on adjacent tissue. This energy deposition within a tumour can produce local bioeffects resulting in thermal chemo- and radiosensitization. MR-HIFU has been shown to be safe and feasible in a companion phase I study for recurrent rectal cancer. The purpose of this study is to determine the feasibility of MR-HIFU in treating primary rectal tumours. Methods: With ethics approval, the anatomic characteristics and surrounding structures of rectal tumours diagnosed at Sunnybrook from 2014-2019 were retrospectively analyzed. Three orthogonal views of MR images were used to determine the potential ultrasound (US) beam path and organs at risk (OAR). In part 2 of the study, the gross tumour volume was delineated for 30 rectal tumours (10 low, mid &high). Image datasets were imported into the Sonalleve MR-HIFU workstation for virtual treatment simulation and planning to determine tumour targetability, coverage, optimal patient set-up, and transducer positioning. Results: Of the 105 tumours analyzed, 36, 52, and 17 were low, mid, and high, respectively. The average width of the acoustic window (sciatic notch) for the US beam path was 5.8 ± 1.4cm, average tumour length was 5.24 ± 2.0cm, and average beam path (skin to tumour edge) was 7.3 ± 1.9cm. Eighty one percent of tumours were ≤ 0.3cm from an OAR. Of the 24 virtually simulated tumours to date, 6/8 lower, 6/8 mid, and 1/8 upper rectal tumours were targetable by MR-HIFU. Conclusions: This is the first virtual analysis to evaluate MR-HIFU HT targetability in primary rectal cancer. Results from this study will support MR-HIFU HT as an option to enhance the treatment of primary rectal cancer. Acknowledgments: This study has been funded by the Canadian Cancer Society. Patient & tumour characteristics. [Table: see text]

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Андреева, Т. А., А. Е. Беркович, Н. Ю. Быков, С. В. Козырев та А. Я. Лукин. "Фокусированный ультразвук высокой интенсивности: тепловой нагрев и разрушение биологической ткани". Журнал технической физики 90, № 9 (2020): 1516. http://dx.doi.org/10.21883/jtf.2020.09.49685.54-20.

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The paper presents the results of a numerical study of the processes of heating and destruction of biological tissue by a series of high-intensity focused ultrasound (HIFU) pulses generated by a multi-element transducer. Tumor treatment programs that differ in the spatial localization of focal points in the tissue (Archimedes spiral, “square” spiral), the number of pulses and the delay between pulses are considered. A significant effect of the parameters of a series of pulses and the perfusion process on the boundaries of the proceeded region in the considered range of moderate radiation intensities was established. It is shown that over time, the process of heat propagation in tissue becomes quasispherical and weakly depends on the type of ablation program. The possibility of using this process property to optimize the protocols of HIFU medical procedures is discussed.

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Son, Keon-Ho, Young-Ki Cho, Dae-Seung Kim, Myung-Deok Kim, and Kook-Jin Kang. "Flat HIFU transducer with a sawtooth-shaped ultrasound radiation face." Journal of the Korean Physical Society 63, no. 8 (October 2013): 1566–75. http://dx.doi.org/10.3938/jkps.63.1566.

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23

Chen, Gin-Shin, Jonathan Cannata, Ruibin Liu, Hsu Chang, and K. Kirk Shung. "DESIGN AND FABRICATION OF HIGH-INTENSITY FOCUSED ULTRASOUND PHASED ARRAY FOR LIVER TUMOR THERAPY." Biomedical Engineering: Applications, Basis and Communications 21, no. 03 (June 2009): 187–92. http://dx.doi.org/10.4015/s1016237209001246.

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Noninvasive surgery of the liver tumors has been carried out by using the high-intensity focused ultrasound (HIFU). However, the liver tumor can be moved by the human respirations and heartbeats, which may cause the ablation and damage of normal tissues during the sonications of HIFU. The purpose of this study was to design and fabricate a cylindrical HIFU phased array transducer for treating the moving liver tumor efficiently. The total number of the element was 512 but only 256 channels were required since the elements along the elevation direction were connected in pairs with respect to the central line of the array. Field II software was used to simulate the acoustic field, and a formula for predicting the spatial averaged intensity at focus was developed based on the practical factors. The results of the simulations showed that the cylindrical HIFU phased array in water had a dynamic focusing range from 145 to 175 mm in the depth direction and a steering range from -15 to 15 mm in azimuthal direction with respect to the center of the array. After the dissipation of cables and the attenuation of various media, the designed array could still generate the intensity at focus up to 1095 W/cm2 when the input electrical power was approximately 410 W. The prototype of the array was fabricated and the preliminary test was completed. The testing results showed that each element of the array prototype can work well.

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Sang, Pil Gyu, Deblina Biswas, Seung Jin Lee, Sang Min Won, Donghee Son, Jong G. Ok, Hui Joon Park, and Hyoung Won Baac. "Experimental Demonstration of a Stacked Hybrid Optoacoustic-Piezoelectric Transducer for Localized Heating and Enhanced Cavitation." Micromachines 12, no. 10 (October 18, 2021): 1268. http://dx.doi.org/10.3390/mi12101268.

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Laser-generated focused ultrasound (LGFU) is an emerging modality for cavitation-based therapy. However, focal pressure amplitudes by LGFU alone to achieve pulsed cavitation are often lacking as a treatment depth increases. This requires a higher pressure from a transmitter surface and more laser energies that even approach to a damage threshold of transmitter. To mitigate the requirement for LGFU-induced cavitation, we propose LGFU configurations with a locally heated focal zone using an additional high-intensity focused ultrasound (HIFU) transmitter. After confirming heat-induced cavitation enhancement using two separate transmitters, we then developed a stacked hybrid optoacoustic-piezoelectric transmitter, which is a unique configuration made by coating an optoacoustic layer directly onto a piezoelectric substrate. This shared curvature design has great practical advantage without requiring the complex alignment of two focal zones. Moreover, this enabled the amplification of cavitation bubble density by 18.5-fold compared to the LGFU operation alone. Finally, the feasibility of tissue fragmentation was confirmed through a tissue-mimicking gel, using the combination of LGFU and HIFU (not via a stacked structure). We expect that the stacked transmitter can be effectively used for stronger and faster tissue fragmentation than the LGFU transmitter alone.

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Foster, Matt, Marta Betcke, Ben Cox, and Bradley E. Treeby. "Weakly nonlinear ray tracing approximations for focused ultrasound propagation." Journal of the Acoustical Society of America 154, no. 4_supplement (October 1, 2023): A180. http://dx.doi.org/10.1121/10.0023194.

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Focused ultrasound is used in a therapeutic treatment (HIFU) and uses ultrasound waves to non-invasively destroy malignant cells inside the human body. The technique works by sending a high-energy beam of ultrasound into the tissue using a focused transducer. Numerically modeling HIFU presents a problem due to nonlinear effects leading to the formation of harmonics of the source frequency. Each harmonic requires a finer grid to resolve, rapidly increasing computational complexity. This work will focus on the derivation and benefits of two ray tracing methods using weakly nonlinear ray theory formed by different asymptotic expansions of the governing acoustic equations. The first has the ray equations identical to those from linear ray theory while the amplitude equation is a nonlinear transformation of the Burgers’ equation. In the second method the Eikonal and transport equations are coupled which results in ray trajectories which depend on the amplitude.

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Cilleros, Celia, Aurélien Dupré, Yao Chen, Jeremy Vincenot, Michel Rivoire, and David Melodelima. "Intraoperative HIFU Ablation of the Pancreas Using a Toroidal Transducer in a Porcine Model. The First Step towards a Clinical Treatment of Locally Advanced Pancreatic Cancer." Cancers 13, no. 24 (December 20, 2021): 6381. http://dx.doi.org/10.3390/cancers13246381.

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Apart from palliative chemotherapy, no other therapy has been proven effective for the treatment of locally advanced pancreatic tumors. In this study, an intraoperative high-intensity focused ultrasound (HIFU) device was tested in vivo to demonstrate the feasibility of treating the pancreatic parenchyma and tissues surrounding the superior mesenteric vessels prior to clinical translation of this technique. Twenty pigs were included and treated using a HIFU device equipped with a toroidal transducer and an integrated ultrasound imaging probe. Treatments were performed with energy escalation (from 30 kJ to 52 kJ). All treatments resulted in visible (macroscopically and in ultrasound images) homogeneous thermal damage, which was confirmed by histology. The dimensions of thermal lesions measured in ultrasound images and those measured macroscopically were correlated (r = 0.82, p < 0.05). No arterial spasms or occlusion were observed at the lowest energy setting. Temporary spasm of the peripancreatic artery was observed when using an energy setting greater than 30 kJ. The possibility of treating the pancreas and tissues around mesenteric vessels without vascular thrombosis holds great promise for the treatment of locally advanced pancreatic cancers. If clinically successful, chemotherapy followed by HIFU treatment could rapidly become a novel treatment option for locally advanced pancreatic cancer.

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Kwon, Da Sol, Jin Ho Sung, Chan Yuk Park, and Jong Seob Jeong. "Phase-Inverted Multifrequency HIFU Transducer for Lesion Expansion: A Simulation Study." IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 65, no. 7 (July 2018): 1125–32. http://dx.doi.org/10.1109/tuffc.2018.2830108.

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Wang, Jiaqiu, Xu Xiao, Zhihong Huang, and Andreas Melzer. "3D-printing based Transducer Holder for Robotic Assisted Ultrasound Guided HIFU." Procedia Manufacturing 30 (2019): 3–10. http://dx.doi.org/10.1016/j.promfg.2019.02.002.

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Civale, John, Robert Clarke, Ian Rivens, and Gail ter Haar. "The use of a segmented transducer for rib sparing in HIFU treatments." Ultrasound in Medicine & Biology 32, no. 11 (November 2006): 1753–61. http://dx.doi.org/10.1016/j.ultrasmedbio.2006.06.005.

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30

Seo, K., K. Ichizuka, H. Aoki, S. Yoshizawa, S. Umemura, M. Kushima, M. Nakamura, et al. "P11.05: Fundamental study for fetal therapy by using an improved HIFU transducer." Ultrasound in Obstetrics & Gynecology 46 (September 2015): 158. http://dx.doi.org/10.1002/uog.15425.

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Andrés, Diana, Ian Rivens, Petros Mouratidis, Noé Jiménez, Francisco Camarena, and Gail ter Haar. "Holographic Focused Ultrasound Hyperthermia System for Uniform Simultaneous Thermal Exposure of Multiple Tumor Spheroids." Cancers 15, no. 9 (April 28, 2023): 2540. http://dx.doi.org/10.3390/cancers15092540.

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Hyperthermia is currently used to treat cancer due to its ability to radio- and chemo-sensitize and to stimulate the immune response. While ultrasound is non-ionizing and can induce hyperthermia deep within the body non-invasively, achieving uniform and volumetric hyperthermia is challenging. This work presents a novel focused ultrasound hyperthermia system based on 3D-printed acoustic holograms combined with a high-intensity focused ultrasound (HIFU) transducer to produce a uniform iso-thermal dose in multiple targets. The system is designed with the aim of treating several 3D cell aggregates contained in an International Electrotechnical Commission (IEC) tissue-mimicking phantom with multiple wells, each holding a single tumor spheroid, with real-time temperature and thermal dose monitoring. System performance was validated using acoustic and thermal methods, ultimately yielding thermal doses in three wells that differed by less than 4%. The system was tested in vitro for delivery of thermal doses of 0–120 cumulative equivalent minutes at 43 °C (CEM43) to spheroids of U87-MG glioma cells. The effects of ultrasound-induced heating on the growth of these spheroids were compared with heating using a polymerase chain reaction (PCR) thermocycler. Results showed that exposing U87-MG spheroids to an ultrasound-induced thermal dose of 120 CEM43 shrank them by 15% and decreased their growth and metabolic activity more than seen in those exposed to a thermocycler-induced heating. This low-cost approach of modifying a HIFU transducer to deliver ultrasound hyperthermia opens new avenues for accurately controlling thermal dose delivery to complex therapeutic targets using tailored acoustic holograms. Spheroid data show that thermal and non-thermal mechanisms are implicated in the response of cancer cells to non-ablative ultrasound heating.

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Huang, Wenchang, Jiaqi Li, Shuai Wu, Yan He, Xiangxin Li, Zhitian Shen, and Yaoyao Cui. "Dual-Frequency Impedance Matching Network Design Using Genetic Algorithm for Power Ultrasound Transducer." Micromachines 15, no. 3 (February 29, 2024): 344. http://dx.doi.org/10.3390/mi15030344.

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Dual-frequency ultrasounds have demonstrated significant potential in augmenting thermal ablation efficiency for tumor treatment. Ensuring proper impedance matching between the dual-frequency transducer and the power amplifier system is imperative for equipment safety. This paper introduces a novel dual-frequency impedance matching network utilizing L-shaped topology and employing a genetic algorithm to compute component values. Implementation involved an adjustable capacitor and inductor network to achieve dual-frequency matching. Subsequently, the acoustic parameters of the dual-frequency HIFU transducer were evaluated before and after matching, and the effects of ultrasound thermal ablation with and without matching were compared. The proposed dual-frequency impedance matching system effectively reduced the standing wave ratio at the two resonance points while enhancing transmission efficiency. Thermal ablation experiments with matching circuits showed improved temperature rise efficiencies at both frequencies, resulting in an expanded ablation zone. The dual-frequency impedance matching method significantly enhances the transmission efficiency of the dual-frequency ultrasound system at two operational frequencies, thereby ensuring equipment safety. It holds promising prospects for application in dual-frequency ultrasound treatment.

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Treweek, Benjamin C., Jacob H. Brody, Alper Erturk, S. H. Swift, Chandler Smith, Cameron A. McCormick, Timothy Walsh, and Nathan W. Moore. "Large-scale simulation of high-intensity focused ultrasound with Sierra/SD." Journal of the Acoustical Society of America 153, no. 3_supplement (March 1, 2023): A271. http://dx.doi.org/10.1121/10.0018815.

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High-frequency simulations of acoustic wave propagation are known to be computationally challenging, and the difficulty is compounded for large domains. For problems like high-intensity focused ultrasound (HIFU) with coupling between piezoelectric and acoustic media, both challenges are present. The larger domain sizes, higher-order elements, and greater levels of refinement necessary in such simulations result in millions of degrees of freedom, large system matrices, and substantial memory requirements, raising the need for parallel high-performance computing (HPC). Sierra/SD is a massively parallel HPC application developed for finite element method simulations in structural dynamics and acoustics. In this work, Sierra/SD is used to simulate an acoustic pulse from a piezoelectric transducer focused on an elastic scatterer in a fluid medium. Three-dimensional simulation results are presented for the acoustic field in the fluid and the stress field in the scatterer, and performance is compared between Sierra/SD and COMSOL Multiphysics for smaller geometries. Finally, to showcase the expanded analysis possibilities afforded by HPC for HIFU, an example is presented using a support vector machine to determine a decision boundary for maximum stress in the scatterer. [SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.]

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Zubair, Muhammad, and Robert Dickinson. "Calculating the Effect of Ribs on the Focus Quality of a Therapeutic Spherical Random Phased Array." Sensors 21, no. 4 (February 9, 2021): 1211. http://dx.doi.org/10.3390/s21041211.

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The overlaying rib cage is a major hindrance in treating liver tumors with high intensity focused ultrasound (HIFU). The problems caused are overheating of the ribs due to its high ultrasonic absorption capability and degradation of the ultrasound intensity distribution in the target plane. In this work, a correction method based on binarized apodization and geometric ray tracing approach was employed to avoid heating the ribs. A detailed calculation of the intensity distribution in the focus plane was undertaken to quantify and avoid the effect on HIFU beam generated by a 1-MHz 256-element random phased array after the ultrasonic beam passes through the rib cage. Focusing through the ribs was simulated for 18 different idealized ribs-array configurations and 10 anatomically correct ribs-array configurations, to show the effect of width of the ribs, intercostal spacing and the relative position of ribs and array on the quality of focus, and to identify the positions that are more effective for HIFU applications in the presence of ribs. Acoustic simulations showed that for a single focus without beam steering and for the same total acoustic power, the peak intensity at the target varies from a minimum of 211 W/cm2 to a maximum of 293 W/cm2 for a nominal acoustic input power of 15 W, whereas the side lobe level varies from 0.07 Ipeak to 0.28 Ipeak and the separation between the main lobe and side lobes varies from 2.5 mm to 6.3 mm, depending on the relative positioning of the array and ribs and the beam alignment. An increase in the side lobe level was observed by increasing the distance between the array and the ribs. The parameters of focus splitting and the deterioration of focus quality caused by the ultrasonic propagation through the ribs were quantified in various possible different clinical scenarios. In addition to idealized rib topology, anatomical realistic ribs were used to determine the focus quality of the HIFU beam when the beam is steered both in axial and transverse directions and when the transducer is positioned at different depths from the rib cage.

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Turner, Ben, and David Cranston. "A Review of High-Intensity Focused Ultrasound." International Journal of Translational Medicine 4, no. 1 (March 12, 2024): 197–207. http://dx.doi.org/10.3390/ijtm4010011.

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For 80 years, high-intensity focused ultrasound (HIFU) has been the subject of interest in medical research. It is a non-invasive procedure that causes the death of cells in a very select area through one of two mechanisms, either heat or cavitation. While diagnostic ultrasound is well known in the medical profession and ultrasound is also used in physiotherapy, high-intensity focused ultrasound is less known but is becoming increasingly important as a non-invasive tool that can be used in many ways, including in the treatment of several cancers as well as benign uterine fibroids. Other interesting developments are underway, including its use in the treatment through an intact skull of essential tremors and the tremor associated with Parkinson’s disease, and in a modified form, it is used to target drug delivery to the brain due to its potential opening of the blood–brain barrier. The depth of penetration of HIFU is variable depending on the type of transducer used and the distance from it. Clinical trials of abdominal malignancies and benign uterine fibroids are reviewed in this article along with potential side effects of the procedure. Over the past two decades, the technology has improved considerably, and the clinical indications have broadened. The current limitations of the technology are also discussed, along with the potential advances in the field that may be made over the next decade.

36

Karaböce, B., and H. O. Durmuş. "Visual Investigation of Heating Effect in Liver and Lung Induced by a HIFU Transducer." Physics Procedia 70 (2015): 1225–28. http://dx.doi.org/10.1016/j.phpro.2015.08.264.

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37

Vincenot, Jeremy, David Melodelima, Françoise Chavrier, Alexandre Vignot, Anthony Kocot, and Jean-Yves Chapelon. "Electronic Beam Steering Used with a Toroidal HIFU Transducer Substantially Increases the Coagulated Volume." Ultrasound in Medicine & Biology 39, no. 7 (July 2013): 1241–54. http://dx.doi.org/10.1016/j.ultrasmedbio.2013.01.019.

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38

Lorton, Orane, Pauline Coralie Guillemin, Andrea Peloso, Yacine M’Rad, Lindsey Alexandra Crowe, Thibaud Koessler, Pierre-Alexandre Poletti, Sana Boudabbous, Alexis Ricoeur, and Rares Salomir. "In Vivo Thermal Ablation of Deep Intrahepatic Targets Using a Super-Convergent MRgHIFU Applicator and a Pseudo-Tumor Model." Cancers 15, no. 15 (August 3, 2023): 3961. http://dx.doi.org/10.3390/cancers15153961.

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Background: HIFU ablation of liver malignancies is particularly challenging due to respiratory motion, high tissue perfusion and the presence of the rib cage. Based on our previous development of a super-convergent phased-array transducer, we aimed to further investigate, in vivo, its applicability to deep intrahepatic targets. Methods: In a series of six pigs, a pseudo-tumor model was used as target, visible both on intra-operatory MRI and post-mortem gross pathology. The transcostal MRgHIFU ablation was prescribed coplanar with the pseudo-tumor, either axial or sagittal, but deliberately shifted 7 to 18 mm to the side. No specific means of protection of the ribs were implemented. Post-treatment MRI follow-up was performed at D7, followed by animal necropsy and gross pathology of the liver. Results: The pseudo-tumor was clearly identified on T1w MR imaging and subsequently allowed the MRgHIFU planning. The peak temperature at the focal point ranged from 58–87 °C. Gross pathology confirmed the presence of the pseudo-tumor and the well-delineated MRgHIFU ablation at the expected locations. Conclusions: The specific design of the transducer enabled a reliable workflow. It demonstrated a good safety profile for in vivo transcostal MRgHIFU ablation of deep-liver targets, graded as challenging for standard surgery.

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Auboiroux, Vincent, Erik Dumont, Lorena Petrusca, Magalie Viallon, and Rares Salomir. "An MR-compliant phased-array HIFU transducer with augmented steering range, dedicated to abdominal thermotherapy." Physics in Medicine and Biology 56, no. 12 (May 23, 2011): 3563–82. http://dx.doi.org/10.1088/0031-9155/56/12/008.

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40

George, Benedikt, Michael Fink, Helmut Ermert, Stefan J. Rupitsch, Stefan Lyer, and Christoph Alexiou. "Guiding and Accumulation of Magnetic Nanoparticles Employing High Intensity Focused Ultrasound for Drug Targeting Applications." Current Directions in Biomedical Engineering 5, no. 1 (September 1, 2019): 589–92. http://dx.doi.org/10.1515/cdbme-2019-0148.

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AbstractMagnetic Drug Targeting (MDT) is a cancer treatment technique that enables a local chemotherapy. In MDT, chemotherapeutic drugs are bound to magnetic nanoparticles and are accumulated in the tumor area by means of an external magnetic field. Unfortunately, a single magnet can only generate a pulling magnetic force. However, in some applications a pushing force on the nanoparticles could be advantageous. One way to realize pushing forces is to exploit the acoustic radiation force based on the nonlinearity of sound propagation in fluid media generated by a high intensity focused ultrasonic transducer. In this context, we built a test setup was built to investigate the utility of High Intensity Focused Ultrasound (HIFU) to generate a pushing force on the magnetic nanoparticles. The results show that the acoustic radiation force can be employed for particle guidance to achieve concentration differences similar to those obtained by using an electromagnet.

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Mylonas, Nicos, and Christakis Damianou. "A Prototype MR Compatible Positioning Device for Guiding a Focused Ultrasound System for the Treatment of Abdominal and Thyroid Cancer." International Journal of Monitoring and Surveillance Technologies Research 1, no. 4 (October 2013): 48–60. http://dx.doi.org/10.4018/ijmstr.2013100105.

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A prototype magnetic resonance imaging (MRI)-compatible positioning device that navigates a high intensity focused ultrasound (HIFU) transducer is presented. The intended application is to treat eventually tumours in the abdominal and thyroid. The positioning device has 3 user-controlled stages that allow access to various targets using a top to bottom coupling approach. Materials and Methods. The positioning device incorporates only MRI compatible materials such as piezoelectric motors, ABS plastic, brass screws, and brass rack and pinion. Results The MRI compatibility and the accuracy of the system were successfully demonstrated in an open MRI scanner. The robot has the ability to accurately move the transducer thus creating discrete and overlapping lesions in rabbit liver in vivo. This simple, cost effective positioning device can be placed mostly on the structure of an open MRI gantry. Due to the size of this positioning device, the proposed prototype in its current form cannot be used in any closed MRI system. The novelty of this positioning device is the MRI compatible design and its intended application which is the treatment of tumors in the abdominal area using focused ultrasound. This system can be utilized in the future to treat patients with cancer in the liver, kidney, pancreas and thyroid provided that the accuracy of the positioning device is greatly improved.

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Ma, Jianguo, Sijia Guo, Di Wu, Xuecang Geng, and Xiaoning Jiang. "Design, fabrication, and characterization of a single-aperture 1.5-MHz/3-MHz dual-frequency HIFU transducer." IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 60, no. 7 (July 2013): 1519–29. http://dx.doi.org/10.1109/tuffc.2013.2724.

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43

Gélat, P., G. ter Haar, and N. Saffari. "A comparison of methods for focusing the field of a HIFU array transducer through human ribs." Physics in Medicine and Biology 59, no. 12 (May 27, 2014): 3139–71. http://dx.doi.org/10.1088/0031-9155/59/12/3139.

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44

Jong Seob Jeong. "Dual concentric-sectored HIFU transducer with phase-shifted ultrasound excitation for expanded necrotic region: a simulation study." IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 60, no. 5 (May 2013): 924–31. http://dx.doi.org/10.1109/tuffc.2013.2649.

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Wu, Chih-Ching, Chiung-Nien Chen, Ming-Chih Ho, Wen-Shiang Chen, and Po-Huang Lee. "Using the Acoustic Interference Pattern to Locate the Focus of a High-Intensity Focused Ultrasound (HIFU) Transducer." Ultrasound in Medicine & Biology 34, no. 1 (January 2008): 137–46. http://dx.doi.org/10.1016/j.ultrasmedbio.2007.07.001.

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Chen, J., S. LeBlang, A. Hananel, R. Aginsky, J. Perez, M. Gofeld, Y. Shir, and J. F. Aubry. "An incoherent HIFU transducer for treatment of the medial branch nerve: Numerical study and in vivo validation." International Journal of Hyperthermia 37, no. 1 (January 1, 2020): 1219–28. http://dx.doi.org/10.1080/02656736.2020.1828628.

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47

Ribault, M., J. Y. Chapelon, D. Cathignol, and A. Gelet. "Differential Attenuation Imaging for the Characterization of High Intensity Focused Ultrasound Lesions." Ultrasonic Imaging 20, no. 3 (July 1998): 160–77. http://dx.doi.org/10.1177/016173469802000302.

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High intensity focused ultrasound (HIFU) is an effective technique for creating coagulative necrotic lesions in biological tissue, with a view to treating localized tumors. Although good results have already been obtained, notably in urology, current systems lack a real time monitoring system to check the efficacy of the treatment procedures. This study describes the development and assessment of a noninvasive system for making local measurements of attenuation variations during HIFU treatment procedures. An apparatus (Ablatherm, Edap-Technomed, France), combining a 2.5 MHz therapeutic transducer and a 5.5 MHz twin plane imaging probe (connected to an ultrasound scanner), was used to produce lesions. The rf signals needed to calculate the attenuation were recorded as outputs from the ultrasound scanner, before and after the high intensity firing sequences, which were performed on ten pieces of porcine liver. Each firing sequence involved producing a lesion volume comprising 42 individual lesions. A number of recordings were also made without producing lesions, in order to test the reproducibility of the measurements. The attenuation function was evaluated locally using the centroid and the multinarrowband methods. Initially, changes in the integrated attenuation αbar; (mean attenuation in the 4–7 MHz range) and the attenuation slope β were examined for the lesion volume. β values did not vary significantly within this range, whereas α values varied significantly (in the region of 86% of the initial level) in comparison to measurements performed without forming lesions. The differential attenuation Δα (representing local variations in α) was subsequently used to generate images revealing the lesion areas. There was a strong similarity between these ‘Δα images’ and the lesion volumes defined by the operator. ‘Δα images’ offer several advantages over existing attenuation imaging techniques. Any problems related to the heterogeneity of the medium are eliminated, since only the change in attenuation is taken into account. Furthermore, there is no need to compensate for diffraction when estimating Δα, as the rf signals are captured in exactly the same positions before and after treatment. This technique can be used during in vivo treatment procedures. It can be implemented in real time, since the computational algorithms (based primarily on FFT calculations) are very fast. The technique should provide clinical practitioners with valuable qualitative and quantitative information for use in HIFU ultrasound surgery.

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Sanchez, M., V. Barrere, I. Treilleux, N. Chopin, and D. Melodelima. "Development of a noninvasive HIFU treatment for breast adenocarcinomas using a toroidal transducer based on preliminary attenuation measurements." Ultrasonics 115 (August 2021): 106459. http://dx.doi.org/10.1016/j.ultras.2021.106459.

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Nicolas, Barbara, François Varray, Jean-Christophe Bera, Audrey sivadon, and Bruno Gilles. "Experimental demonstration of 3D passive cavitation imaging using adaptive beamforming." Journal of the Acoustical Society of America 153, no. 3_supplement (March 1, 2023): A269. http://dx.doi.org/10.1121/10.0018810.

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Interest in passive cavitation imaging has increased in recent years with the development of cavitation-based treatments. Using cross-spectral matrix formalism, adaptive beamformers, such as Capon beamforming, MUSIC, and p-DAS, have been adapted to 2D passive cavitation imaging (PAM) (Polichetti et al., 2020). More recently, we adapted this formalism in 3D to enhance the resolution of PAM using a commercial imaging array. Three beamformers have been extended in both 3D and the Frequency Domain: the DAS beamformer, the Robust Capon Beamformer (RCB) and the MidWay (MW) beamformer. A random sparse array configuration of a multiplexed commercial 2D array is used to reduce the number of channels used for the acquisition and to reconstruct 3D-PAM without degrading the quality of the reconstructed images. Such an approach allows for achieving a versatile well-resolved PAM using conventional research systems. In an experimental situation, the cavitation is initiated by a HIFU transducer at the tip of a needle and monitored with a high-speed camera confirming the presence of cavitation. This initial work allows us to envisage a possible future for 3D cavitation imaging using adaptive algorithms and sparse probes.

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Ramaekers, Pascal, Mario Ries, Chrit T. W. Moonen, and Martijn de Greef. "Improved intercostal HIFU ablation using a phased array transducer based on Fermat's spiral and Voronoi tessellation: A numerical evaluation." Medical Physics 44, no. 3 (February 13, 2017): 1071–88. http://dx.doi.org/10.1002/mp.12082.

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