Jean-Yves Chapelon

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Vibro-acoustography method is explored for detecting and imaging brachytherapy metal seeds in gel phantoms. In a previous paper, we have shown that some immersed objects' resonance frequencies could be detected by vibro-acoustography. Here, we use this idea to optimize the vibro-acoustic excitation of two different sized brass seeds implanted in an agar gel(More)
Elastography is an imaging technique based on strain estimation in soft tissues under quasi-static compression. The stress is usually created by a compression plate, and the target is imaged by an ultrasonic linear array. This configuration is used for breast elastography, and has been investigated both theoretically and experimentally. Phenomena such as(More)
PURPOSE To evaluate the histologic effects and clinical outcomes of high-intensity focused ultrasound (HIFU) delivered by miniaturized annular transducers for ciliary body coagulation in an animal study. METHODS Eighteen eyes of 18 rabbits were insonified with a ring comprising a six-sector transducer, to produce a 12.8-mm-diameter circular lesion. Six(More)
The purpose of our study was to assess the feasibility of using ultrasound radiation force as a safe vibration source for transient MR elastography (t-MRE). We present a theoretical framework to predict the phase shift of the complex MRE signal, the temperature elevation due to ultrasound, and safety indicators (I(SPPA), I(SPTA), MI). Next, we report wave(More)
PURPOSE To evaluate the relative safety and potential efficacy of high-intensity focused ultrasound cyclocoagulation by a miniaturized annular device containing six piezoceramic transducers in patients with refractory glaucoma. METHODS This was a three-center prospective interventional pilot study. Twelve eyes of 12 patients with refractory glaucoma were(More)
The study investigates a new sonication strategy with high-intensity focused ultrasound (HIFU), aiming for improvement of the original Ablatherm procedure in the prostate cancer treatment. The currently implemented and clinically used method (defined as reference) uses a single-element transducer, operated with 60% duty cycle. To implement the novel(More)
Image-guided thermal ablation offers minimally invasive options for treating hepatocellular carcinoma and colorectal metastases in liver. Here, the feasibility and the potential benefit of active temperature control for MR-guided percutaneous ultrasound ablation was investigated in pig liver. An MR-compatible interstitial ultrasound applicator (flat(More)
BACKGROUND Surgery is the only curative treatment in patients with colorectal liver metastases (CLM), but only 10-20% of patients are eligible. High Intensity Focused Ultrasound (HIFU) technology is of proven value in several indications, notably prostate cancer. Its intra-operative use in patients with CLM has not previously been studied. Preclinical work(More)
New curative and palliative treatments are needed to respond to the poor prognosis of esophageal cancer. The purpose of this study was to determine whether magnetic resonance imaging (MRI) and MR thermometry can be used to monitor the thermal ablation induced by an intraluminal high-intensity ultrasound applicator positioned in the esophagus. Experiments(More)
External beam radiation therapy or high intensity focused ultrasound for localized prostate cancer: a matched pair analysis in the prostate-specific antigen era Background: In the absence of randomised study data institutional series have shown High Intensity Focused Ultrasound (HIFU) to produce excellent overall and cancer specific survival rates in(More)