Jung Woo Choe

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Ultrasound induced microbubble cavitation can cause enhanced permeability across natural barriers of tumors such as vessel walls or cellular membranes, allowing for enhanced therapeutic delivery into the target tissues. While enhanced delivery of small (<1nm) molecules has been shown at acoustic pressures below 1MPa both in vitro and in vivo, the delivery(More)
Atrial fibrillation, the most common type of cardiac arrhythmia, now affects more than 2.2 million adults in the US alone. Currently, electrophysiological interventions are performed under fluoroscopy guidance, which besides its harmful ionizing radiation does not provide adequate soft-tissue resolution. Intracardiac echocardiography (ICE) provides realtime(More)
A ring array provides a very suitable geometry for forward-looking volumetric intracardiac and intravascular ultrasound imaging. We fabricated an annular 64-element capacitive micromachined ultrasonic transducer (CMUT) array featuring a 10-MHz operating frequency and a 1.27-mm outer radius. A custom software suite was developed to run on a PC-based imaging(More)
3D ultrasound imaging is becoming increasingly prevalent in the medical field. Compared to conventional 2D imaging systems, 3D imaging can provide a detailed view of tissue structures that makes diagnosis easier for the physicians. In addition, 2D image slices can be formed at various orientations to the transducer, making the examination less dependent on(More)
Atrial fibrillation is the most common type of cardiac arrhythmia that now affects over 2.2 million adults in the United States alone. Currently fluoroscopy is the most common method for guiding interventional electrophysiological procedures. We are developing a 9-F forward-looking intracardiac ultrasound catheter for real-time volumetric imaging. We(More)
Synthetic phased array (SPA) beamforming with Hadamard coding and aperture weighting is an optimal option for real-time volumetric imaging with a ring array, a particularly attractive geometry in intracardiac and intravascular applications. However, the imaging frame rate of this method is limited by the immense computational load required in synthetic(More)
In 3-D ultrasound imaging where 2-D transducer arrays with more than hundreds of elements are used, sparse arrays can be used to reduce the number of active ultrasound channels. Under a restriction of desired number of active channels, we can maximize the image quality by optimally choosing the positions of active elements. Here we use the method of(More)
Real-time volumetric ultrasound imaging systems require transmit and receive circuitry to generate ultrasound beams and process received echo signals. The complexity of building such a system is high due to requirement of the front-end electronics needing to be very close to the transducer. A large number of elements also need to be interfaced to the(More)
Atrial fibrillation, the most common type of cardiac arrhythmia, now affects more than 2.2 million adults in the US alone. Currently, electrophysiological interventions are performed under fluoroscopy guidance, a procedure that introduces harmful ionizing radiation without providing adequate soft-tissue resolution. Intracardiac echocardiography (ICE)(More)
We designed and implemented a flexible real-time volumetric ultrasound imaging system for capacitive micromachined ultrasonic transducer (CMUT) arrays, consisting of an ultrasound data acquisition system, an FPGA board, and a host PC. The system works with arbitrary-shaped CMUT arrays and non-standard beamforming methods, as well as with regularshaped CMUT(More)