Yoav Medan

Technion - Israel Institute of Technology | technion · Electrical Engineering Research Center

Ultrasound-mediated targeted drug delivery is a therapeutic modality under development with the potential to treat cancer. Its ability to produce local hyperthermia and cell poration through cavitation non-invasively makes it a candidate to trigger drug delivery. Hyperthermia offers greater potential for control, particularly with magnetic resonanc...

Proton resonance frequency shift thermometry may be improved by combining multibaseline and referenceless thermometry.

Purpose: Respiratory motion makes hepatic ablation using high intensity focused ultrasound (HIFO) challenging. Previous HIFU liver treatment had required apnea induced during general anesthesia. We describe and test a system that allows treatment of the liver in the presence of breathing motion. Methods: Mapping a signal from an external respira...

A focused ultrasound system comprises a transducer having a multiplicity of transducer elements, drive circuitry that generates and outputs a plurality of drive signals, each offset by a respective phase difference, and a controller for selectively coupling the drive signals to respective transducer elements, the controller including a plurality of...

An image-guide therapy system comprises a thermal treatment device (e.g., an ultrasound transducer) configured for transmitting a therapeutic energy beam, and The system further comprises an imaging device (e.g., a magnetic resonant imaging (MRI) device) configured for acquiring images of the target tissue mass and the thermal treatment device. The...

The phase background of a proton resonance frequency shift treatment image may be estimated by fitting a combination of baseline images to the treatment image.

Phase aberrations and attenuations caused by bone can defocus HIFU in the brain and organs behind the ribcage. To refocus the beam, MR-ARFI can be used to measure tissue displacements created by each element in the transducer, and optimize driving signal delays and amplitudes. We introduce a new MR-ARFI-based autofocusing method that requires many...

Reducing toxicity and improving uptake of cancer drugs in tumors are important goals of targeted drug delivery (TDD). Ultrasonic drug release from various encapsulants has been a focus of many research groups. However, a single standard ultrasonic device, viable for use by biologists, is not currently present in the market. The device reported here...

Recently, ultrasonic drug release has been a focus of many research groups for stimuli responsive drug release. It has been demonstrated that a focused ultrasound (FUS) beam rapidly increases the temperature at the focused tissue area. One potential mechanism of drug targeting is to utilize the induced heat to release or increase penetration of che...

High intensity focused ultrasound (HIFU) in the abdomen can be sensitive to acoustic aberrations that can exist in the beam path of a single sonication. Having an accurate method to quickly visualize the transducer focus without damaging tissue could assist with executing the treatment plan accurately and predicting these changes and obstacles. By...

We report on the development of an instrument for hybrid 'sonoptic' cavitation studies. A focused ultrasound transducer is housed in a custom built chamber, which permits optical access to the focal volume, without perturbing the propagating acoustic field. This configuration allows pulsed-laser irradiation of the fluid at the focus, and simultaneo...

e13062 Background: Cyclodextrins (CDs) have the ability to carry drugs in their cavities. CD derivatives conjugated with a targeting moiety are expected to be drug carriers capable of targeting cancer cells with high specificity. In order to obtain effective drug carrier complexes, efficient methods for increasing the drug inclusion ability of the...

Magnetic resonance thermometry using the proton resonance frequency (PRF) shift is a promising technique for guiding thermal ablation. For temperature monitoring in moving organs, such as the liver and the heart, problems with motion must be addressed. Multi-baseline subtraction techniques have been proposed, which use a library of baseline images...

Magnetic resonance guided ultrasonic therapy is a promising minimally invasive technology for constantly growing variety of clinical applications. Delivery of focused ultrasound (FUS) energy to the targeted point with optimal intensity is highly desired; however, due to tissue aberrations, optimal focal intensity is not always achieved. Especially...

In this work a more time efficient approach for tissue assessment with MR‐ARFI is proposed. During HIFU treatments gadolinium‐free assessment of treated tissue is highly desirable. MR‐ARFI allows measuring tissue displacement in the focal spot. Therefore raster‐scanning the ultrasound focal spot through the tissue of interest can give information a...

A new approach for sampling rate conversion of digitally sampled signals is presented. The approach enables conversion from any given source sampling rate to any desired target sampling rate even if the source and destination clocks are not synchronous. The importance of algorithm is in a communication system where the sampling is done on one syste...

Let n vertices be distributed on the circumference of a circle in the plane. We find, for every n, the minimum number of cycles with no crossing edges such that every pair of vertices is adjacent on at least one cycle. The problem arises from the design of a train shuttle service between n cities with continuous guaranteed service at all times, and...

The author presents an efficient exploitation of a super resolution pitch estimate in waveform speech coders such as LPC (linear predictive coding), CELP (code-excited linear prediction), and TDHS. Despite the compression/quality gain afforded with using super resolution pitch, the computational resources required to interpolate the speech signal t...

Based on a new similarity model for the voice excitation process, a novel pitch determination procedure is derived. The unique features of the proposed algorithm are infinite (super) resolution, better accuracy than the difference limen for F ₀, robustness to noise, reliability, and modest computational complexity. The algorithm is instr...

In this paper we present a parallelization of the Cooley- Tukey FFT algorithm that is implemented on a shared-memory MIMD (non-vector) machine that was built in the Dept. of Computer Science, Tel Aviv University. A parallel algorithm is presented for one dimension Fourier transform with performance analysis. For a large array of complex numbers to...

A multimicrophone noise cancellation algorithm is described. The algorithm was adapted for use as a preprocessor to speech recognition device, with the aim of overcoming the extreme noise sensitivity of such devices, while still allowing a natural interaction with the recognition device that does not involve wearing or holding any special microphon...

The problem of spectrum analysis of harmonic signals which are periodic or at least quasi-periodic, such as human voice, is addressed. An efficient and accurate pitch-synchronized spectral analysis scheme for obtaining the Fourier coefficients of a harmonic signal, sampled at an arbitrary rate above the Nyquist critical rate, is outlined. The pitch...

Not Available

Not Available

Not Available

An accurate, robust, and reliable pitch detection scheme is outlined. The algorithm extracts the pitch with a very high resolution (i.e., as a real number) despite the finite (8-kHz) resolution of the sampled speech sequence. This makes it possible to analyze the pitch variation process in disarthric patients for medical purposes and to develop an...

The usefulness of hearing aids is severely limited by the existence of the `cocktail party effect'. This is due to the very high sensitivity of hearing aid wearers to interfering sounds. A description is given of the result of some work aimed at alleviating this problem. The approach involved the use of an adaptive array of microphones to cancel ou...

An efficient short-time spectral analysis scheme of periodic, or quasi-periodic signals, such as voiced speech, is outlined. Generally, the signal is sampled at a fixed sampling rate irrespective of the signal period. As a consequence, the resulting sampled sequence may not preserve the periodic structure. The proposed scheme is based on an implici...

It appears that one of the most important factors limiting the usefulness of hearing aids is the high sensitivity of hearing aid users to interfering sounds. In this work, the possibility of utilizing computing power that could be packaged into a unit the size of a hearing aid in order to cancel out noises before they reach the ear was investigated...

Application of new data compression schemes to aided inertial navigation systems is presented. The need for data compression is motivated by the fact that the external aiding system generates frequent but inaccurate position measurements, which have to be processed by a processor whose computation capability is limited. Two new data compression tec...

This paper introduces a new L-D measurement update algorithm. The new algorithm is superior to the conventional one when only part of the states are directly related to the measurements. As the number of these states decreases, the computational efficiency of the new algorithm improves. The new algorithm is developed and discussed and its computati...

This paper introduces a new L-D measurement update algorithm. The new algorithm is superior to the conventional one when the ratio between the dimension of the state vector and the number of states directly related to the measurements is greater than one. The computational efficiency of the new algorithm is directly proportional to this ratio. The...

A recursive linear optimal estimation method is presented which processes a batch of measured data at each estimation point. Due to this feature the new method serves as a data compression scheme. This scheme is an integrated one in the sense that the optimization is performed on a prefilter/estimator combination. The method is derived and compared...

A new data compression technique of a new class was recently introduced. Although the rationale and the equations involved in the application of the technique were fully presented, an error analysis of the actual (true) estimation error was not provided. Due to the unconventional operations involved in the application of the technique, the standard...

A recursive linear optimal estimation method is presented which processes a batch of measured data at each estimation point. Due to this feature the new method serves as a data compression scheme. This scheme is an integrated one in the sense that the optimization is performed on a pre-filter/estimator combination. The method is derived and compare...