scholarly journals Piezoelectric annular array for large depth of field photoacoustic imaging

2011 ◽  
Vol 2 (9) ◽  
pp. 2655 ◽  
Author(s):  
K. Passler ◽  
R. Nuster ◽  
S. Gratt ◽  
P. Burgholzer ◽  
G. Paltauf
Keyword(s):  
Photoacoustic Imaging ◽  
Depth Of Field ◽  
Large Depth ◽  
Annular Array

Annular array detector for large depth of field photoacoustic macroscopy

2017 ◽  
Author(s):  
Paul R. Torke ◽  
Robert Nuster ◽  
Guenther Paltauf
Keyword(s):  
Depth Of Field ◽  
Array Detector ◽  
Large Depth ◽  
Annular Array

The Improvement and Quantitative Assessment of B-Mode Images Produced by an Annular Array/Cone Hybrid

1983 ◽  
Vol 5 (3) ◽  
pp. 195-213 ◽  
Author(s):  
M. S. Patterson ◽  
F. S. Foster
Keyword(s):  
Quantitative Assessment ◽  
Breast Tissue ◽  
Imaging Systems ◽  
Depth Of Field ◽  
Scattering Medium ◽  
Human Breast ◽  
Human Breast Tissue ◽  
New Approach ◽  
Annular Array

Hybrid ultrasound imaging systems, which combine spherical focusing on transmit with axicon focusing on receive, provide excellent resolution over a useful depth of field. This paper presents a new hybrid design with improved sensitivity, in which the axicon focusing is achieved by two conical mirrors and a PZT 5A disk cut into 8 sectors. We have investigated two methods of processing the signals from the 8 sectors. In the first, phase insensitive sector addition (PISA), the B-scan is formed from the sum of the 8 demodulated signals. In the second, multiplicative processing (MP), the 8 rf waveforms are multiplied and the resultant is demodulated to form the image. Both techniques result in smoothed speckle but degraded lateral resolution. As well, MP decreases the off-axis sensitivity of the system and artifacts characteristic of axicon focusing. Quantitative assessment of the effects of PISA and MP was performed using a new approach called contrast-to-speckle ratio (CSR). The CSR data, which is a measure of the image contrast of cylindrical voids in a random scattering medium relative to contrast fluctuations due to speckle, shows the superiority of PISA and MP. This conclusion is supported by images of in vitro human breast tissue.

Backscatter properties of two-layer phantoms using a high-frequency ultrasound annular array

2022 ◽  
Author(s):  
Wakana Saito ◽  
Masaaki Omura ◽  
Jeffrey A. KETTERLING ◽  
Shinnosuke Hirata ◽  
Kenji YOSHIDA ◽  
...  
Keyword(s):  
Sound Field ◽  
Correction Method ◽  
Frequency Domain Analysis ◽  
Depth Of Field ◽  
High Frequency Ultrasound ◽  
Backscatter Coefficient ◽  
Annular Array ◽  
Array Transducer ◽  
Rat Livers ◽  
Frequency Ultrasound

Abstract In a previous study, an annular-array transducer was employed to characterize homogeneous scattering phantoms and excised rat livers using backscatter envelope statistics and frequency domain analysis. A sound field correction method was also applied to take into account the average attenuation of the entire scattering medium. Here, we further generalized the evaluation of backscatter coefficient (BSC) using the annular array in order to study skin tissues with a complicated structure. In layered phantoms composed of two types of media with different scattering characteristics, the BSC was evaluated by the usual attenuation correction method which revealed an expected large difference from the predicted BSC. In order to improve the BSC estimate, a correction method that applied the attenuation of each layer as a reference combined with a method that corrects based on the attenuation of the analysis position were applied. It was found that the method using the average attenuation of each layer is the most effective. This correction method is well adapted to the extended depth of field provided by an annular array.

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