Gel phantom for use in high-intensity focused ultrasound dosimetry

Lafon, Cyril; Zderic, Vesna; Noble, Misty L.; Yuen, Jonathan C.; Kaczkowski, Peter J.; Sapozhnikov, Oleg A.; Chavrier, F.; Crum, Lawrence A.; Vaezy, Shahram

doi:10.1016/j.ultrasmedbio.2005.06.004

Cited by 232 publications

(178 citation statements)

References 15 publications

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“…However, the attenuation of this gel was similar to water and thus it did not provide good mimicking of tissue attenuation properties (Greaby 2005). Developing a tissue mimicking gel that will have the acoustic and physical properties of human soft tissues while keeping the transparency would be very beneficial in the image-guided hemostasis studies (Lafon et al 2005), allowing both good mimicking of transcutaneous HIFU treatment and easy visual observation of the injury site.…”

Section: Discussion and Summarymentioning

confidence: 99%

Pulsatile Flow Phantom for Ultrasound Image-Guided HIFU Treatment of Vascular Injuries

Greaby

Zderic

Vaezy

2007

Ultrasound in Medicine & Biology

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A pulsatile flow phantom was developed for studies of ultrasound image-guided High Intensity Focused Ultrasound (HIFU) application in transcutaneous hemostasis of injured blood vessels. The flow phantom consisted of a pulsatile pump system with instrumented excised porcine carotid artery, which was imbedded in a transparent agarose gel to model structural configuration of in-vivo tissues. Heparinized porcine blood was circulated through the phantom. The artery was injured using an 18 Gauge needle to model a penetrating injury in human peripheral vasculature. A HIFU transducer with the diameter of 7 cm, focal length of 6.3 cm and frequency of 3.4 MHz was used to seal the puncture. Ultrasound imaging was used to localize and target the puncture site, and monitor the HIFU treatment. Triphasic blood flows present in the human arteries were reproduced, with flow rates of 50-500 ml/min, pulse rates of 62-138 beats/min, and peak pressures of 100-250 mmHg. The penetrating injury of an artery was mimicked successfully in the flow phantom setting, and was easily visualized both optically through the transparent gel and with Power Doppler ultrasound imaging. Hemostasis was achieved in 55 ± 31 s (n=9) of HIFU application. Histological observations showed that a HIFU-sealed puncture was filled with clotted blood and covered with a fibrin cap. The pulsatile flow phantom provides a controlled and repeatable environment for studies of transcutaneous imageguided HIFU application in hemostasis of a variety of blood vessel injuries.

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Section: Discussion and Summarymentioning

confidence: 99%

Pulsatile Flow Phantom for Ultrasound Image-Guided HIFU Treatment of Vascular Injuries

Greaby

Zderic

Vaezy

2007

Ultrasound in Medicine & Biology

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“…The gel phantom consisted of polyacrylamide and a 7% concentration of bovine serum albumen ͑BSA͒ and has been used in several studies as a test phantom for HIFU dosimetry studies. 28,[33][34][35] While the acoustic properties of the phantom material such as sound speed and density are similar to tissue, the absorption coefficient is about three times lower than in tissue. The lower absorption leads to more pronounced nonlinear effects than might be observed in tissue at similar source power levels.…”

Section: Methodsmentioning

confidence: 99%

Acoustic characterization of high intensity focused ultrasound fields: A combined measurement and modeling approach

Canney

Bailey

Crum

et al. 2008

The Journal of the Acoustical Society of America

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257

246

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Acoustic characterization of high intensity focused ultrasound ͑HIFU͒ fields is important both for the accurate prediction of ultrasound induced bioeffects in tissues and for the development of regulatory standards for clinical HIFU devices. In this paper, a method to determine HIFU field parameters at and around the focus is proposed. Nonlinear pressure waveforms were measured and modeled in water and in a tissue-mimicking gel phantom for a 2 MHz transducer with an aperture and focal length of 4.4 cm. Measurements were performed with a fiber optic probe hydrophone at intensity levels up to 24 000 W / cm 2 . The inputs to a Khokhlov-Zabolotskaya-Kuznetsov-type numerical model were determined based on experimental low amplitude beam plots. Strongly asymmetric waveforms with peak positive pressures up to 80 MPa and peak negative pressures up to 15 MPa were obtained both numerically and experimentally. Numerical simulations and experimental measurements agreed well; however, when steep shocks were present in the waveform at focal intensity levels higher than 6000 W / cm 2 , lower values of the peak positive pressure were observed in the measured waveforms. This underrepresentation was attributed mainly to the limited hydrophone bandwidth of 100 MHz. It is shown that a combination of measurements and modeling is necessary to enable accurate characterization of HIFU fields.

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“…The merit of urethane is that it does not require mixing with another substance to increase its attenuation. Previous study on BSA gel phantom [6] showed that the attenuation increased linearly with increase in BSA concentration. Mixing with another substance results in lower transparency.…”

Section: Temperature Sensitive Phantommentioning

confidence: 89%

“…It is important that the medium for visualization using MTLC is transparent and it is not desirable to mix with another substance. In addition, urethane is more durable than BSA gel [6] and carrageenan gel [12]. MTLC visualization is reversible.…”

Section: Temperature Sensitive Phantommentioning

confidence: 99%

“…In previous studies on methods of evaluating temperature distribution in a medium exposed by an HIFU beam, thermocouples [4], infrared camera [5], BSA gel [6], non-ionic surface agent [7], thermochromic liquid crystal (TLC) sheet [8], and MR thermometry [9] were used. Since the thermocouple-based method measures temperature at a single point, many thermocouples are needed for 3D measurement.…”

Section: Introductionmentioning

confidence: 99%

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Visualization of Temperature Distribution around Focal Area and Near Fields of High Intensity Focused Ultrasound Using a 3D Measurement System

Iwahashi

Tang

Matsui

et al. 2018

ABE

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High intensity focused ultrasound (HIFU) is one of the promising minimally invasive therapeutic methods. Focused ultrasound creates coagulation area with minimally invasiveness. Reduction of thermal damage in non-target area during HIFU therapy as well as effective coagulation of the target area are important. In developing a safe and effective HIFU system and control algorithm for HIFU beam manipulation, experimental evaluation of 3D temperature distribution is required to verify the performance of the system under development. In previous studies, several methods for evaluating 3D temperature distribution were introduced, such as MRI thermometry. This method requires consideration of MRI compatibility of the HIFU system. Other methods including thermocouples and thermochromic liquid crystal (TLC) sheet have been used to visualize temperature distribution in experimental acoustic phantoms. However, there were several limitations in evaluating 3D temperature distribution during HIFU exposure. In this study, a 3D temperature distribution measurement system using micro-capsulated thermochromic liquid crystal (MTLC) was developed. We fabricated an optically transparent temperature sensitive phantom containing MTLC that emits a re ectance spectrum depending on temperature. The 3D temperature distribution was visualized using a light sheet method. The temperature distribution in the optical phantom during HIFU exposure was determined with errors as low as 0.6 C. Using this system, temperature distribution induced by HIFU exposure was visualized using different focusing methods to evaluate their performance.

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Gel phantom for use in high-intensity focused ultrasound dosimetry

Cited by 232 publications

References 15 publications

Pulsatile Flow Phantom for Ultrasound Image-Guided HIFU Treatment of Vascular Injuries

Pulsatile Flow Phantom for Ultrasound Image-Guided HIFU Treatment of Vascular Injuries

Acoustic characterization of high intensity focused ultrasound fields: A combined measurement and modeling approach

Visualization of Temperature Distribution around Focal Area and Near Fields of High Intensity Focused Ultrasound Using a 3D Measurement System

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