Paul L. M. J. van Neer

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Recently, the measurement of phase transfer functions (PTFs) of piezoelectric transducers has received more attention. These PTFs are useful for e.g. coding and interference based imaging methods, and ultrasound contrast microbubble research. Several optical and acoustic methods to measure a transducer's PTF have been reported in literature. The optical(More)
In medical ultrasound, fundamental imaging (FI) uses the reflected echoes from the same spectral band as that of the emitted pulse. The transmission frequency determines the trade-off between penetration depth and spatial resolution. Tissue harmonic imaging (THI) employs the second harmonic of the emitted frequency band to construct images. Recently,(More)
Ultrasound contrast agents (UCAs) are small micro-bubbles that behave nonlinearly when exposed to an ultrasound wave. This nonlinear behavior can be observed through the generated higher harmonics in a back-scattered echo. In past years several techniques have been proposed to detect or image harmonics produced by UCAs. In these proposed works, the(More)
Current medical diagnostic echo systems are mostly using harmonic imaging. This means that a fundamental frequency (e.g., 2 MHz) is transmitted and the reflected and scattered higher harmonics (e.g., 4 and 6 MHz), produced by nonlinear propagation, are recorded. The signal level of these harmonics is usually low and a well-defined transfer function of the(More)
Pressure amplitude measurement is important for general research on ultrasound. Because it requires high accuracy, it is usually done using a hydrophone calibrated by an accredited laboratory. In this paper, a method is proposed for estimating the pressure amplitude in the ultrasound field using an uncalibrated single-element transducer and(More)
Current transesophageal probes are designed for adults and are used both in the operating theatre for monitoring as well as in the outpatient clinic for patients with specific indications, like obesity, artificial valves, etc. For newborns (<5 kg), transesophageal echocardiography (TEE) is not possible because the current probes are too big for introducing(More)
Transesophageal echocardiography (TEE) uses the esophagus as an imaging window to the heart. This enables cardiac imaging without interference from the ribs or lungs and allows for higher frequency ultrasound to be used compared with transthoracic echocardiography (TTE). TEE facilitates the successful imaging of obese or elderly patients, where TTE may be(More)
Spatial resolution in medical ultrasound images is a key component in image quality and an important factor for clinical diagnosis. In early systems, the lateral resolution was optimal in the focus but rapidly decreased outside the focal region. Improvements have been found in, e.g., dynamic-receive beamforming, in which the entire image is focused in(More)
Catheterization remains the gold standard for bladder volume assessment, but it is invasive, uncomfortable to the patient and introduces the risk of infections and traumas. Acoustic measurement of the bladder volume reduces the need for a urinary catheter. Recently, a new method to non-invasively measure the volume of liquid filled cavities in vivo on the(More)
With the ongoing drive to integrate more functionality and processing power on the same semiconductor area, the device structures have become 3D. Such structures, like FinFETs and their successors GAA nanowire FETs, bring on new challenges to measure their geometry and material properties non-destructively at the nanometer scale. Photo Thermal Acoustic(More)