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Content based search in audio-visual collections requires media specific analysis for extracting low level features to be efficiently indexed and searched. We present the SAPIR media framework for analyzing digital content and representing the extracted features in a common schema, used to index and search content in a P2P network. The framework contains splitters of compound objects into simple objects...
High-frequency ultrasound (HFU, > 15 MHz) is an effective means of obtaining fine-resolution images of biological tissues for applications such as opthalmologic, dermatologic, and small animal imaging. HFU has two inherent drawbacks. First, HFU images have a limited depth of field (DOF) because of the short wavelength and the low fixed F-number of conventional HFU transducers. Second, HFU can be...
Very-high-frequency (>30 MHz) ultrasound allows fine-resolution imaging at the expense of depth-of-field and acoustic penetration depth. Mechanically scanned annular arrays have demonstrated that they can extend depth-of-field significantly. This study investigates chirp-coded excitation to increase penetration depth. A 40-MHz, five-element annular array with a focal length of 12 mm and a total...
Prostate brachytherapy uses small, titanium-shelled radioactive seeds to locally treat prostate cancer. Unfortunately, during the implantation procedure, needles inserted under the guidance of transrectal-ultrasound (TRUS) cause gland movement, which often results in seed misplacement and suboptimal dosimetry. In a previous study, an algorithm based on singular spectrum analysis (SSA) was described...
Current acoustic contrast agents are designed to be used in the low-MHz range (< 10 MHz) but there is a growing interest in using agents with high-frequency ultrasound (HFU, > 15 MHz). Polymer-shelled contrast agents represent the newest generation of agents and their HFU response has been relatively unexplored. Experiments were performed with polycaprolactone-shelled agents (POINT Biomedical,...
We aim to validate the theoretical frameworks independently established by Lizzi et al. and Insana et al. relating spectral parameters derived from ultrasonic (US) radio-frequency (RF) echo signals to scatterer properties. A 35-MHz transducer was used to acquire US RF echo signals from isolated, living, uveal melanoma cells suspended in a liquid culture medium. Spectral parameters for these cells...
Characterizing occurrence of ultrasound contrast agent (UCA) microbubble destruction is important for development of functional and therapeutic applications. Previously [Ammi, et. al., 2006], it was demonstrated that post-excitation acoustic emissions detected with passive cavitation detection (PCD) result from inertial cavitation (IC) of UCA after shell rupture. That work relied on time-consuming...
Ultrasound-guided brachytherapy using small titanium-shelled radioactive seeds is an effective means of treating prostate cancer. Unfortunately, implantation using needles inserted transperitoneally causes gland movement and distortion, which often results in dosimetry errors. If actual seed locations could be determined in the operating room, then corrections to dosimetry errors could be made immediately...
High-frequency (i.e., > 15 MHz) ultrasound (HFU) permits fine-resolution imaging. However, the limited depth of field (DOF) and acoustic penetration depth of HFU waves limits its clinical use to the assessment of shallow diseases such as ocular or dermatological conditions. The aim of this study is to use modern annular array transducer technology and coded signals to improve DOF and penetration...
High-frequency ultrasound (HFU) shows promises for with fine-resolution imaging. However, the limited depth of field (DOF) and penetration depth of HFU waves mitigates in significance for clinical evaluation. The aim of this study is to use modern annular transducer technology and coded excitation to simultaneously improve DOF and penetration depth. A 20-MHz, five-element annular array with a focal...
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