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Your search keyword '"Zhou, Yufeng"' showing total 49 results
Start Over Author "Zhou, Yufeng" Publication Type Conference Materials
49 results on '"Zhou, Yufeng"'

28. Failure Analysis of Shift Gas Tubes

Author

Shi, Jin, primary, Wang, Yian, additional, Liu, Wen, additional, Jing, Weike, additional, Zhou, Yufeng, additional, Shao, Shanshan, additional, Zhang, Kai, additional, Chen, Qiuping, additional, and Li, Wurong, additional

Published
2014
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43. In Vitro Comparison between HM-3 and MODULARIS Lithotripters

Author

Leitao, Victor A., primary, Simmons, W. Neal, additional, Zhou, Yufeng, additional, Qin, Jun, additional, Cocks, Franklin H., additional, Fehre, Jens, additional, Granz, Bernd, additional, Nanke, Ralf, additional, Preminger, Glenn M., additional, and Zhong, Pei, additional

Published
2007
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47. Producing Uniform Lesion Pattern in HIFU Ablation.

Author

Zhou, Yufeng, Kargl, Steven G., and Hwang, Joo Ha

Subjects
MEDICAL imaging systems, THERMAL diffusivity, TUMOR diagnosis, SCANNING electron microscopy, INTRAVASCULAR ultrasonography
Abstract

High intensity focused ultrasound (HIFU) is emerging as a modality for treatment of solid tumors. The temperature at the focus can reach over 65° C denaturing cellular proteins resulting in coagulative necrosis. Typically, HIFU parameters are the same for each treated spot in most HIFU control systems. Because of thermal diffusion from nearby spots, the size of lesions will gradually become larger as the HIFU therapy progresses, which may cause insufficient treatment of initial spots, and over-treatment of later ones. It is found that the produced lesion pattern also depends on the scanning pathway. From the viewpoint of the physician creating uniform lesions and minimizing energy exposure are preferred in tumor ablation. An algorithm has been developed to adaptively determine the treatment parameters for every spot in a theoretical model in order to maintain similar lesion size throughout the HIFU therapy. In addition, the exposure energy needed using the traditional raster scanning is compared with those of two other scanning pathways, spiral scanning from the center to the outside and from the outside to the center. The theoretical prediction and proposed algorithm were further evaluated using transparent gel phantoms as a target. Digital images of the lesions were obtained, quantified, and then compared with each other. Altogether, dynamically changing treatment parameters can improve the efficacy and safety of HIFU ablation. [ABSTRACT FROM AUTHOR]

Published
2009
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49. Comparison of pathway in high intensity focused ultrasound (HIFU) lesion production.

Author

Zhou, Yufeng, Kargl, Steven, Kim, Kwang, and Hwang, Joo Ha

Abstract

High intensity focused ultrasound (HIFU) is being evaluated for non-invasive treatment of solid tumors. The temperature at the HIFU focus can reach over 65 deg C denaturing cellular proteins and resulting in coagulative necrosis and lesion formation. One common method for delivering HIFU therapy clinically is using the spot accumulation method that delivers sequential individual treatment spots. Because of thermal diffusion from nearby treatment spots, the size of subsequent lesions will gradually become larger as the HIFU therapy progresses, which may cause insufficient treatment of the initial spots, and over-treatment of later spots unless parameters are changed during treatment. A new pathway for HIFU treatment is proposed and compared with the conventional sequential path. Modeling, in vitro phantom and ex vivo bovine liver experiments demonstrate that the new treatment path produces more uniform lesions than the conventional treatment path (p<0.05). The relationship between lesion area/volume and delivered ultrasound energy and dose-dependent discrepancies between scanning paths were also studied. In addition, the temperature changes in the ex vivo system were measured using a thermocouple array. Altogether, the new treatment path appears to be advantageous for producing more uniform lesions without modifying HIFU parameters during treatment or significantly increasing the scanning time. [ABSTRACT FROM AUTHOR]

Published
2007
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