Development of an Ultrasonic Elastography System for Assessing the Mechanical Properties of Biological Tissues
| Autor: | Li-JinKang, 康瓈今 |
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| Rok vydání: | 2012 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 100 In clinics, the manual palpation is used to diagnose the pathological and stiffness changes. But palpation highly depends on the judgment of the physician to perform the diagnosis. The techniques of ultrasonic elastography have been used to characterize the palpation. It provides the objective and alternative information for clinical diagnosis. The study aims to implement an ultrasound elasticity image system for evaluating the biological tissue elasticity. The pressure sensor and 5MHz ultrasound pulser are combined with the two single axis (X axis, Z axis) step motors to scan and compress the objects. The cross-correlation technique is used to process the pre- and post-compression of radio frequency (RF) signals. From the measured data we can calculate the elasticity modulus and strain distribution of the objects. The custom-made gelatin and pork tissue was used as phantoms for system validation. Our results show that system can effectively differentiate the objects within the elasticity difference. Our approach can provide the elasticity information and increase the discernment which cannot obtain from tradition B-mode images. The signal-to-noise ratio of strain was increased by increasing the compression depth. The traditional cross-correlation method has decorrelation when the deformation of objects causes the waveform changes. Our method relies on the significant interface echo signal can reduce the correlation noise interference. If we cannot observe the boundary in B-mode, we cannot estimate the elastic correctly. If the interference can be removed we can use the correlation technique to measure the elasticity accurately. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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