Abstract:The proposed NRT method makes it possible to attain very high spatial resolution without compromising the thermoacoustic signal strength. This makes the imaging performance to be limited by the available bandwidth of the ultrasonic detector rather than by the microwave pulse duration. It is overall expected that the combination of pulsed near-field coupling with optimal choice of energy dissipation elements will generate a practical modality that can scale its application to small and larger volumes alike, whi… Show more
“…It has been mentioned that pulses of nanosecond-range duration that can carry hundreds of millijoule energy are ideal for obtaining good signal-to-noise ratio (SNR) and spatial resolution in many biological imaging applications [15]. The amplitude of TA signal is proportional to the pressure caused by thermal expansion.…”
Abstract-Microwave induced thermo-acoustic tomography (MITAT) is a developing technique for biomedical applications, especially for early breast cancer detection. In this paper, impacts of short microwave pulse on thermo-acoustic (TA) signals are analyzed and verified through some experimental comparisons. In these experiments, short microwave pulses with widths of 10 ns and 500 ns are employed as radiation resources. TA signals generated from a cubic sample are analyzed in both time-and frequency-domain. A trapezoid sample is also performed for experimental comparing. Different from previous literature, the effects of rising edge of radiation microwave pulse have been intensively studied. Experimental results demonstrate that shorter rising edge duration conducts broader bandwidth of TA signal, which give rise to better spatial resolution for tomography imaging.
“…It has been mentioned that pulses of nanosecond-range duration that can carry hundreds of millijoule energy are ideal for obtaining good signal-to-noise ratio (SNR) and spatial resolution in many biological imaging applications [15]. The amplitude of TA signal is proportional to the pressure caused by thermal expansion.…”
Abstract-Microwave induced thermo-acoustic tomography (MITAT) is a developing technique for biomedical applications, especially for early breast cancer detection. In this paper, impacts of short microwave pulse on thermo-acoustic (TA) signals are analyzed and verified through some experimental comparisons. In these experiments, short microwave pulses with widths of 10 ns and 500 ns are employed as radiation resources. TA signals generated from a cubic sample are analyzed in both time-and frequency-domain. A trapezoid sample is also performed for experimental comparing. Different from previous literature, the effects of rising edge of radiation microwave pulse have been intensively studied. Experimental results demonstrate that shorter rising edge duration conducts broader bandwidth of TA signal, which give rise to better spatial resolution for tomography imaging.
“…Some experimental MITAT systems have been developed and been reported [12,13,[15][16][17]. In order to validate the performance of the integrated simulation approach, we have developed a MITAT system.…”
Section: Mitat Systemmentioning
confidence: 99%
“…Two-and three-dimensional (2-D and 3-D) imaging of breast tissue phantoms or real breast tissue specimens have been investigated [14][15][16][17]. In the study of MITAT techniques, a fast and accurate simulation approach is necessary to help designing and optimizing system.…”
Abstract-Microwave induced thermo-acoustic tomography (MI-TAT) has great potential in early breast cancer detection because it utilizes the advantages of both microwave imaging and ultrasound imaging. In this paper, a fast and efficient simulation approach based on a hybrid method which combines finite integration time domain (FITD) method and pseudo-spectral time domain (PSTD) method is developed. By using this approach, energy deposition of biology tissue illuminated by electromagnetic fields can be accurately simulated. Meanwhile, acoustic properties of the tissue can be efficiently simulated as well. Based on this approach, a MITAT model is created and some simulated results are analyzed. Furthermore, some real breast tissues are adopted to perform the thermo-acoustic imaging experiment. Comparisons between experimental and simulated results are made. The feasibility and effectiveness of the proposed approach are demonstrated by both numerical simulations and experimental results.
“…Because the microwave radiation absorption rates between tumors and normal tissues are quite different [8,9], the thermo-acoustic image will have high contrast compared with that of acoustic imaging system which has been widely used. Near-field thermo-acoustic tomography system has great potentials for breast cancer imaging [10][11][12][13]. In the system, the imaged sample is placed in the vicinity of antenna to assure optimal near-field coupling.…”
Abstract-Microwave induced thermo-acoustic tomography (MI-TAT) has become a keen research topic in recent years due to its great potential in early breast cancer detection. A secure and accurate MI-TAT system has been established. Some experiments have been made to demonstrate the performance of the MITAT system. Based on an experiment using phantom, some quantitative features of the system have been obtained. Some imaging experiments with real human breast cancer tissues are performed to demonstrate its effectiveness and the potential in clinical diagnosis. Images with both high contrast and fine spatial resolution are achieved by using time reversal mirror (TRM) technique in the imaging processing. Moreover, comparisons between the MITAT system result and an ultrasound imaging system result are made. From the comparison, the MITAT system shows its advantages of better contrast over the ultrasound imaging system. The system and the experiments in this paper verify the mechanism of MITAT for breast cancer detection and provide a prototype basis for clinical practice.
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