scholarly journals Thermal Ablation and High-Resolution Imaging Using a Back-to-Back (BTB) Dual-Mode Ultrasonic Transducer: In Vivo Results

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1580
Author(s):  
Hae Gyun Lim ◽  
Hyunhee Kim ◽  
Kyungmin Kim ◽  
Jeongwoo Park ◽  
Yeonggeun Kim ◽  
...  
Keyword(s):  
High Resolution ◽  
Thermal Ablation ◽  
Ex Vivo ◽  
Ultrasonic Transducer ◽  
High Intensity Focused Ultrasound ◽  
Coagulation Necrosis ◽  
Single Element ◽  
Focal Region ◽  
Dual Mode

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.

scholarly journals Comparison of the synergistic effect of lipid nanobubbles and SonoVue microbubbles for high intensity focused ultrasound thermal ablation of tumors

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1716 ◽  
Author(s):  
Yuanzhi Yao ◽  
Ke Yang ◽  
Yang Cao ◽  
Xuan Zhou ◽  
Jinshun Xu ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
High Intensity ◽  
Thermal Ablation ◽  
Focused Ultrasound ◽  
Malignant Tumors ◽  
Ex Vivo ◽  
Irradiation Time ◽  
Ultrasound Contrast Agent ◽  
High Intensity Focused Ultrasound

Microbubbles (MBs) are considered as an important enhancer for high intensity focused ultrasound (HIFU) treatment of benign or malignant tumors. Recently, different sizes of gas-filled bubbles have been investigated to improve the therapeutic efficiency of HIFU thermal ablation and reduce side effects associated with ultrasound power and irradiation time. However, nanobubbles (NBs) as an ultrasound contrast agent for synergistic therapy of HIFU thermal ablation remain controversial due to their small nano-size in diameter. In this study, phospholipid-shell and gas-core NBs with a narrow size range of 500–600 nm were developed. The synergistic effect of NBs for HIFU thermal ablation was carefully studied both in excised bovine livers and in breast tumor models of rabbits, and made a critical comparison with that of commercial SonoVue microbubbles (SonoVue MBs). In addition, the pathological changes of the targeted area in tumor tissue after HIFU ablation were further investigated. Phosphate buffer saline (PBS) was used as the control. Under the same HIFU parameters, the quantitative echo intensity of B-mode ultrasound image and the volume of coagulative necrosis in lipid NBs groups were significantly higher and larger than that in PBS groups, but could not be demonstrated a difference to that in SonoVue MBs groups bothex vivoandin vivo. These results showed that the synergistic effect of lipid NBs for HIFU thermal ablation were similar with that of SonoVue MBs, and further indicate that lipid NBs could potentially become an enhancer for HIFU thermal ablation of tumors.

scholarly journals In VivoVisualization of Heterogeneous Intratumoral Distribution of Hypoxia-Inducible Factor-1αActivity by the Fusion of High-Resolution SPECT and Morphological Imaging Tests

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Hirofumi Fujii ◽  
Masayuki Yamaguchi ◽  
Kazumasa Inoue ◽  
Yasuko Mutou ◽  
Masashi Ueda ◽  
...  
Keyword(s):  
High Resolution ◽  
Ex Vivo ◽  
Hypoxia Inducible Factor ◽  
Chimeric Protein ◽  
Small Animal ◽  
Ct Scanner ◽  
Heterogeneous Distribution ◽  
Fusion Images ◽  
Intratumoral Distribution

Purpose. We aimed to clearly visualize heterogeneous distribution of hypoxia-inducible factor 1α(HIF) activity in tumor tissuesin vivo.Methods. We synthesized of125I-IPOS, a125I labeled chimeric protein probe, that would visualize HIF activity. The biodistribution of125I-IPOS in FM3A tumor-bearing mice was evaluated. Then, the intratumoral localization of this probe was observed by autoradiography, and it was compared with histopathological findings. The distribution of125I-IPOS in tumors was imaged by a small animal SPECT/CT scanner. The obtainedin vivoSPECT-CT fusion images were compared withex vivoimages of excised tumors. Fusion imaging with MRI was also examined.Results.125I-IPOS well accumulated in FM3A tumors. The intratumoral distribution of125I-IPOS by autoradiography was quite heterogeneous, and it partially overlapped with that of pimonidazole. High-resolution SPECT-CT fusion images successfully demonstrated the heterogeneity of125I-IPOS distribution inside tumors. SPECT-MRI fusion images could give more detailed information about the intratumoral distribution of125I-IPOS.Conclusion. High-resolution SPECT images successfully demonstrated heterogeneous intratumoral distribution of125I-IPOS. SPECT-CT fusion images, more favorably SPECT-MRI fusion images, would be useful to understand the features of heterogeneous intratumoral expression of HIF activityin vivo.

High-Intensity Focused Ultrasound Scattering at Mammal Vertebrae

2020 ◽  
Author(s):  
David Sanford ◽  
Christoph Schaal
Keyword(s):  
High Intensity ◽  
Laboratory Experiments ◽  
Energy Deposition ◽  
Focused Ultrasound ◽  
Complex Geometry ◽  
Ex Vivo ◽  
Pulsed Laser ◽  
High Intensity Focused Ultrasound ◽  
Focal Region ◽  
Homogeneous Media

Abstract High-intensity focused ultrasound (HIFU) is used clinically to heat cells therapeutically or to destroy them through heat or cavitation. In homogeneous media, the highest wave amplitudes occur at a predictable focal region. However, HIFU is generally not used in the proximity of bones due to wave absorption and scattering. Ultrasound is passed through the skull in some clinical trials, but the complex geometry of the spine poses a greater targeting challenge and currently prohibits therapeutic ultrasound treatments near the vertebral column. This paper presents a comprehensive experimental study involving shadowgraphy and hydrophone measurements to determine the spatial distribution of pressure amplitudes from induced HIFU waves near vertebrae. First, a bone-like composite plate that is partially obstructing the induced waves is shown to break the conical HIFU form into two regions. Wave images are captured using pulsed laser shadowgraphy, and hydrophone measurements over the same region are compared to the shadowgraphy intensity plots to validate the procedure. Next, shadowgraphy is performed for an individual, clean, ex-vivo feline vertebra. The results indicate that shadowgraphy can be used to determine energy deposition patterns and to determine heating at a specific location. The latter is confirmed through additional temperature measurements. Overall, these laboratory experiments may help determine the efficacy of warming specific nerve cells within mammal vertebrae without causing damage to adjacent tissue.

scholarly journals Smartphone microendoscopy for high resolution fluorescence imaging

2016 ◽  
Vol 09 (05) ◽  
pp. 1650046 ◽  
Author(s):  
Xiangqian Hong ◽  
Vivek K. Nagarajan ◽  
Dale H. Mugler ◽  
Bing Yu
Keyword(s):  
High Resolution ◽  
Rural Areas ◽  
Ex Vivo ◽  
Cost Effective ◽  
Internal Organs ◽  
Middle Income ◽  
Middle Income Countries ◽  
The Past

High resolution optical endoscopes are increasingly used in diagnosis of various medical conditions of internal organs, such as the cervix and gastrointestinal (GI) tracts, but they are too expensive for use in resource-poor settings. On the other hand, smartphones with high resolution cameras and Internet access have become more affordable, enabling them to diffuse into most rural areas and developing countries in the past decade. In this paper, we describe a smartphone microendoscope that can take fluorescence images with a spatial resolution of 3.1 [Formula: see text]m. Images collected from ex vivo, in vitro and in vivo samples using the device are also presented. The compact and cost-effective smartphone microendoscope may be envisaged as a powerful tool for detecting pre-cancerous lesions of internal organs in low and middle-income countries (LMICs).

scholarly journals A computational atlas of the hippocampal formation using ex vivo , ultra-high resolution MRI: Application to adaptive segmentation of in vivo MRI

NeuroImage ◽  
2015 ◽  
Vol 115 ◽  
pp. 117-137 ◽  
Author(s):  
Juan Eugenio Iglesias ◽  
Jean C. Augustinack ◽  
Khoa Nguyen ◽  
Christopher M. Player ◽  
Allison Player ◽  
...  
Keyword(s):  
High Resolution ◽  
Hippocampal Formation ◽  
Ex Vivo ◽  
Adaptive Segmentation ◽  
High Resolution Mri
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