Name: evaluating targeting accuracy in the focal plane for an ultrasound-guided high-intensity focused ultrasound phased-array system
Uploaded: 2019-03-06T14:45:00
Description: Watch this Scientific Journal Video about Evaluating Targeting Accuracy in the Focal Plane for an Ultrasound-guided High-intensity Focused Ultrasound Phased-array System at JoVE.com

This work has been supported in part by the National Natural Science Foundation of China (81402522), the Shanghai Key Technology R&#38;D Program (17441907400) from the Science and Technology Commission of Shanghai Municipality, and Shanghai Jiao Tong University Medical Engineering Research Fund (YG2017QN40, YG2015ZD10). Zhonghui Medical Technology (Shanghai) Co., Ltd. is also acknowledged for providing the USgHIFU system. The authors thank Wenzhen Zhu and Junhui Dong for the phantom preparation and their assistance in the experiments.

1. Marker design and fabrication
<ol>
	<li>Design a square model using computer-aided design software. Set each side as sticks with lengths of 40 mm and thicknesses of 2 mm. Place a solid ball with a 10 mm diameter at each corner of the square model.</li>
	<li>Use acrylonitrile butadiene styrene photosensitive resin as the material for printing.</li>
	<li>Send the 3D model file to a manufacturer for fabrication.</li>
</ol>
2. Phantom preparation
<ol>
	<li>Attach a plastic cylinder (with a diam...

<ol>
	<li>Wang, S. B., He, C. C., Li, K., Ji, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+of+a+112-channel+phased-array+ultrasonography-guided+focused+ultrasound+system+in+combination+with+switch+of+ultrasound+imaging+plane+for+tissue+ablation.">Design of a 112-channel phased-array ultrasonography-guided focused ultrasound system in combination with switch of ultrasound imaging plane for tissue ablation.</a> 2014 Symposium on Piezoelectricity, Acoustic Waves, and Device Applications (SPAWDA). , 134-137 (2014).</li><li>Choi, J. 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F., Chen, Y. Z., Ji, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+calibration+of+targeting+errors+for+an+ultrasound-guided+high-intensity+focused+ultrasound+system.">The calibration of targeting errors for an ultrasound-guided high-intensity focused ultrasound system.</a> 2017 IEEE International Symposium on Medical Measurements and Applications (MeMeA). , 10-14 (2017).</li><li>Ellens, N. P. 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Robotic components have been used for extracorporeal USgHIFU systems. To evaluate the targeting accuracy of such systems, reference markers11,12,18, in vitro tissue17, tumor-mimic models, and temperature-sensitive phantoms have been used alone or in combination10,20. Compared with the protocols in those studies, this method is more clinically rele...

The phased array is increasingly designed and equipped in HIFU systems1,2,3,4,5,6,7. In USgHIFU phased-array systems, a US imaging probe is usually mounted in the central hole of the spherical HIFU transducer1,2,8. The probe is rotatable for targeting and image reconstruction in the three-dimensional space9. Precise targeting is required for the safety and efficacy of HIFU treatment. However, most of the studies for the evaluation of targeting accuracy have been performed for magnetic resonance-guided HIFU systems or USgHIFU systems configured with a self-focused HIFU transducer10,11,12,13,14,15,16. The purpose of the method described below is to evaluate the targeting accuracy in the focal plane for USgHIFU phased array systems.
A bovine muscle/marker-embedded phantom along the clinically relevant beam path is used in the evaluation of the targeting accuracy of a clinical USgHIFU phased-array system. A square model with four balls at the corners is fabricated and embedded, in combination with bovine muscle, into the transparent phantom. A regular hexagon is selected as the target based on the positions of the centers of four balls identified in the reconstructed US image on the treatment plane. After HIFU sonications, the treatment plane of the phantom is scanned, and the boundary of the lesion, as well as the positions of the four balls, can be determined in the scanned image. The targeting accuracy can be evaluated by measuring the distance between the centers of target and lesion, as well as three derivative parameters.
The method is simpler than the measurement of the targeting error using robotic movement with a specific reference object11,17,18 and more clinically relevant in comparison to the method based on single focal spot ablation in a homogeneous phantom10. This method can be used in the evaluation of the targeting accuracy of USgHIFU phased array systems. It can be also used for other USgHIFU systems equipped with self-focused HIFU transducers.

<table border="0" cellpadding="0" cellspacing="0" style="width:849px;" width="849">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:233px;">Acrylamide</td>
			<td style="width:276px;">Amresco</td>
			<td style="width:160px;">D403-2</td>
			<td style="width:180px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Acrylic baseboard</td>
			<td>LAO NIAO STORES</td>
			<td>customized</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Acrylic cylindrical water tank&#160;</td>
			<td>LAO NIAO STORES</td>
			<td>customized</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Ammonium persulfate</td>
			<td>Yatai United Chemical Co., Ltd (Wuxi, China)</td>
			<td>2017-03-01</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Beaker</td>
			<td>East China Chemical Reagent Instrument Store</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Bis-acrylamide</td>
			<td>Amresco</td>
			<td>M0172</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Bovine muscle</td>
			<td>Market</td>
			<td style="width:160px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Chopping board</td>
			<td>JIACHI</td>
			<td dir="LTR">JC-ZB40</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Cylindrical plastic&#160;phantom holder</td>
			<td>QIYINPAI</td>
			<td>customized</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Degassed deionized water</td>
			<td style="width:276px;"></td>
			<td style="width:160px;"></td>
			<td>made by the USgHIFU system</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Electric balance</td>
			<td>YINGHENG</td>
			<td>11119453359</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Glass rod</td>
			<td>East China Chemical Reagent Instrument Store</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Knife</td>
			<td>SHIBAZI</td>
			<td dir="LTR">SL1210-C</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Mask</td>
			<td>Medicom</td>
			<td>2498</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">N,N,N&#8217;,N&#8217;&#8211;Tetramethylethylenediamine</td>
			<td>Zhanyun Chemical Co., Ltd (Shanghai, China)</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Rubber glove</td>
			<td>AMMEX</td>
			<td>YZB/MAL 0587-2018</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Scanner</td>
			<td>Fuji Xerox</td>
			<td>DocuPrint M268dw</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Screwdriver</td>
			<td>Stanley</td>
			<td>T6</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Silica gel</td>
			<td>GE</td>
			<td>381</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Square model</td>
			<td>QIYINPAI</td>
			<td>customized</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Stainless steel spoons</td>
			<td>East China Chemical Reagent Instrument Store</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sucker</td>
			<td>East China Chemical Reagent Instrument Store</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Swine muscle</td>
			<td>Market</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">USgHIFU system</td>
			<td>Zhonghui Medical Technology (Shanghai) Co., Ltd.</td>
			<td>SUA-I</td>
			<td></td>
		</tr>
	</tbody>
</table>

evaluating targeting accuracy in the focal plane for an ultrasound-guided high-intensity focused ultrasound phased-array system

Phased arrays are increasingly used as high-intensity focused ultrasound (HIFU) transducers in the existing extracorporeal ultrasound-guided HIFU (USgHIFU) systems. The HIFU transducers in such systems are usually spherical in shape with a central hole where a US imaging probe is mounted and can be rotated. The image on the plane of treatment can be reconstructed through the image sequence acquired during the rotation of the probe. Therefore, the treatment plan can be made on the reconstructed images. In order to evaluate the targeting accuracy in the focal plane of such systems, the protocol of a method using a bovine muscle and marker-embedded phantom is described. In the phantom, four solid balls at the corners of a square resin model serve as the reference markers in the reconstructed image. The target should be moved so that both its center and the center of the square model can coincide according to their relative positions in the reconstructed image. Swine muscle with a thickness of about 30 mm is placed above the phantom to mimic the beam path in clinical settings. After sonication, the treatment plane in the phantom is scanned and the boundary of the associated lesion is extracted from the scanned image. The targeting accuracy can be evaluated by measuring the distance between the centers of target and lesion, as well as three derivative parameters. This method cannot only evaluate the targeting accuracy of the target consisting of multiple focal spots rather than a single focal spot in a clinically relevant beam path of the USgHIFU phased-array system, but it can be also used in the preclinical evaluation or regular maintenance of USgHIFU systems configured with phased-array or self-focused HIFU transducer.

We made phantoms dedicated to evaluating the targeting accuracy of a clinical USgHIFU phased-array system with the targets of three different sizes. Figure 1 displays the US image at angles of 0&#176; and 90&#176;. The interfaces are clear, and the sticks of the square model are bright in the US images. Figure 2 demonstrates the reconstructed US image in the treatment plane and the focal spots of the largest target. The centers o...

Watch this Scientific Journal Video about Evaluating Targeting Accuracy in the Focal Plane for an Ultrasound-guided High-intensity Focused Ultrasound Phased-array System at JoVE.com

Evaluating Targeting Accuracy in the Focal Plane for an Ultrasound-guided High-intensity Focused Ultrasound Phased-array System

This study describes a protocol to evaluate the targeting accuracy in the focal plane of an ultrasound-guided high-intensity focused ultrasound phased-array system.

Phased arrays are increasingly used as high-intensity focused ultrasound (HIFU) transducers in the existing extracorporeal ultrasound-guided HIFU ...

Accurate targeting is essential to ensure safety and efficacy for image-guided, high-intensity focused ultrasound systems. Our protocol can evaluate in targeting accuracy of ultrasound-guided, high-intensity focused ultrasound phase-array systems. This technique can be used to evaluate the targeting accuracy in the treatment plane while taking into consideration the clinically relevant tissue paths.This method can be applied to ultrasound-guided, high-intensity focused ultrasound systems with a self-focused transducer using different ultrasound image reconstruction methods. Visual demonstration of this method can help others fully understand the protocol, especially how to determine the location of the target in the reconstructed ultrasound image. Before making the phantom, fabricate the model.This 3D-printed model is a square with side lengths of 40 millimeters. A solid ball is at each corner. With the model at hand, make the phantom holder.For this, get an acrylic baseboard and an eight-centimeter-diameter plastic cylinder that is three centimeters tall. Use silica gel to attach them to form a holder. Let the assembly sit for one hour.Now, move on to make the phantom from fresh bovine muscle. Slice the muscle into a square with sides of 30 millimeters and 10-millimeter thickness. Ventilate the tissue with a fan for two hours to evaporate moisture.Next, prepare to work with hazardous chemicals. Pour degassed and deionized water into a beaker. Add acrylamide, and stir until it is dissolved.Then, add bis-acrylamide, and stir until dissolved. Finally, add tetramethylethylenediamine, and stir until the solution is uniform. This is solution one.In another beaker with degassed and deionized water, add ammonium persulfate, and stir to dissolve. This is solution two. When the phantom has solidified, retrieve the 3D-printed model, and place it on the phantom surface.With the model in place, the next step is to put the sliced bovine muscle in the middle of the model. Pour the rest of solution one into the phantom holder. Move the bovine muscle to remove air at the interface of the phantom and the slice.Continue by pouring the remainder of the solution two into the phantom holder. Then, stir for five seconds. Adjust the location of the muscle to be at the center of the phantom, and let everything sit for 20 minutes to solidify.Once it has solidified, use a screwdriver to remove the silica gel, holding the cylinder and base together, and slowly detach the two. Start the ultrasound-guided, high-intensity focused ultrasound system. Turn on the water-processing module, and set the circulation speed.To continue, have a cylindrical tank filled with degassed water at room temperature. The tank diameter is 30 centimeters, and its height is 13 centimeters. Get the phantom holder, and place it in the degassed water.Take measures to ensure the holder is fixed tightly in place. Next, move the treatment bed and the therapeutic unit to allow imaging the phantom. The balloon of the therapeutic unit should be immersed in the degassed water.Be prepared with a sample of swine muscle before continuing. The sample should be about 100 millimeters long and be about 30 millimeters thick. Put the sample aside, and slowly move the therapeutic unit up and down.The goal is to make sure the treatment plane is at the upper interface of the sliced bovine muscle and phantom. With the ultrasound imaging probe at zero degrees, move the water tank to make the imaging axis pass through the middle of the two parallel lines in the image. Next, rotate the imaging probe to 90 degrees.Then, move the tank to make the axis pass through the middle of the two parallel lines in the image. Reconstruct the ultrasound image in the treatment plane at the depth of geometric focus. Check that the four balls are clearly shown in the reconstructed image.Also, check if the target is located at the center of the square model. When ready, lift the therapeutic unit in order to place the swine muscle above the phantom. Here, the swine muscle is in position and ready for the next steps.Move the therapeutic unit back into position for imaging. Arrange the depth of geometric focus to be three millimeters beneath the upper surface of the bovine muscle. Continue by setting the parameters for high-intensity focused ultrasound sonication, including the pulse duration and power, among others.Set the exposure time for the chosen hexagonal virtual target and a two-second exposure time for the focal spot at the geometric center of the phase array. Start the sonication, and put a foot on the foot pedal of the sonication instrument. During sonication, observe and record the ultrasound image to allow comparison of the echogenicity of different samples.Remove the phantom before using similarly prepared phantoms to repeat the sonication steps with the other virtual targets. This is an ultrasound image at an angle of zero degrees. An ultrasound image at an angle of 90 degrees is similar.Both images show clear interfaces between the swine muscle, phantom, and bovine muscle. In addition, the sticks of the square model are bright. This is the reconstructed image in the treatment plane.The blue circles encompass the highest average gray value in the red squares and identify the positions of the four balls in the model. The blue circles also determine the center of the square model, which is the center of the targets. The brown squares indicate the focal spots in the largest regular hexagonal target.Determining the location of the four balls in the reconstructed ultrasound image is important for matching the target center with the model center. The chemical materials used for phantom preparation are slightly hazardous. A mask and gloves should be worn during the procedure.

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Ambient Method for the Production of an Ionically Gated Carbon Nanotube Common Cathode in Tandem Organic Solar Cells

A method of fabricating organic photovoltaic (OPV) tandems that requires no vacuum processing is presented. These devices are comprised of two ...

Characterization of Full Set Material Constants and Their Temperature Dependence for Piezoelectric Materials Using Resonant Ultrasound Spectroscopy

During the operation of high power electromechanical devices, a temperature rise is unavoidable due to mechanical and electrical losses, causing the ...

Focused Ion Beam Fabrication of LiPON-based Solid-state Lithium-ion Nanobatteries for In Situ Testing

Focused Ion Beam Fabrication of LiPON-based Solid-state Lithium-ion Nanobatteries for In Situ Testing

Solid-state electrolytes are a promising replacement for current organic liquid electrolytes, enabling higher energy densities and improved safety of ...

Controllable Nucleation of Cavitation from Plasmonic Gold Nanoparticles for Enhancing High Intensity Focused Ultrasound Applications

In this study, plasmonic gold nanoparticles were simultaneously exposed to pulsed near-infrared laser light and high intensity focused ultrasound (HIFU) ...

Multiplexing Focused Ultrasound Stimulation with Fluorescence Microscopy

By focusing low-intensity ultrasound pulses that penetrate soft tissues, LIPUS represents a promising biomedical technology to remotely and safely ...

Evaluating Usability Aspects of a Mixed Reality Solution for Immersive Analytics in Industry 4.0 Scenarios

In medicine or industry, the analysis of high-dimensional data sets is increasingly required. However, available technical solutions are often complex to ...

3D Printing - Evaluating Particle Emissions of a 3D Printing Pen

Three-dimensional (3D) printing as a type of additive manufacturing shows continuing increase in application and consumer popularity. The fused filament ...