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High intensity focused ultrasound

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https://www.readbyqxmd.com/read/28103552/extending-the-utility-of-the-parabolic-approximation-in-medical-ultrasound-using-wide-angle-diffraction-modeling
#1
Joshua E Soneson
Wide-angle parabolic models are commonly used in geophysics and underwater acoustics but have seen little application in medical ultrasound. Here a wide-angle model for continuous-wave high-intensity ultrasound beams is derived which approximates the diffraction process more accurately than the commonly-used Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation without increasing implementation complexity or computing time. A method for preventing the high spatial frequencies often present in source boundary conditions from corrupting the solution is presented...
January 16, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28096917/assessment-of-histopathological-features-of-needle-biopsy-in-recurrent-prostate-cancer-following-salvage-high-intensity-focused-ultrasound
#2
Michele Billia, Khurram M Siddiqui, Susanne Chan, Fan Li, Ali Al-Zahrani, Jose A Gomez, Joseph L Chin
INTRODUCTION: Local recurrence of prostate cancer (PCa) following radiotherapy may be treated with curative intent using salvage high-intensity focused ultrasound (s-HIFU). The interpretation of needle core biopsy specimens following s-HIFU is a daunting task, even for experienced pathologists. We describe various histopathological features encountered in biopsy specimens following whole-gland s-HIFU in one of the largest descriptive studies to date. METHODS: Fifty-five patients with biopsy-proven localized radio-recurrent PCa underwent s-HIFU and transrectal ultrasound (TRUS)-guided prostatic needle biopsies at 180 days post-treatment...
November 2016: Canadian Urological Association Journal, Journal de L'Association des Urologues du Canada
https://www.readbyqxmd.com/read/28090656/real-time-monitoring-of-tissue-displacement-and-temperature-changes-during-mr-guided-high-intensity-focused-ultrasound
#3
Pierre Bour, Fabrice Marquet, Valéry Ozenne, Solenn Toupin, Erik Dumont, Jean-François Aubry, Matthieu Lepetit-Coiffe, Bruno Quesson
PURPOSE: The therapy endpoint most commonly used in MR-guided high intensity focused ultrasound is the thermal dose. Although namely correlated with nonviable tissue, it does not account for changes in mechanical properties of tissue during ablation. This study presents a new acquisition sequence for multislice, subsecond and simultaneous imaging of tissue temperature and displacement during ablation. METHODS: A single-shot echo planar imaging sequence was implemented using a pair of motion-encoding gradients, with alternated polarities...
January 16, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28072572/a-3d-time-reversal-cavity-for-the-focusing-of-high-intensity-ultrasound-pulses-over-a-large-volume
#4
J Robin, B Arnal, M Tanter, M Pernot
Shock wave ultrasound therapy techniques, increasingly used for non-invasive surgery, require extremely high pressure amplitudes in precise focal spots, and large high-power transducers arranged on a spherical shell are usually used to achieve that. This solution allows limited steering of the beam around the geometrical focus of the device at the cost of a large number of transducer elements, and the treatment of large and moving organs like the heart is challenging or impossible. This paper validates numerically and experimentally the possibility of using a time reversal cavity (TRC) for the same purpose...
February 7, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28069222/ultrasound-assisted-extraction-of-bioactive-compounds-from-palm-pressed-fiber-with-high-antioxidant-and-photoprotective-activities
#5
Valéria Dal Prá, Felipe C Lunelli, Raquel Guidetti Vendruscolo, Rafael Martins, Roger Wagner, Ayres P Lazzaretti, Denise M Guimarães Freire, Maria Alexandri, Apostolis Koutinas, Marcio A Mazutti, Marcelo Barcellos da Rosa
This work is focused on the optimization of the ultrasound-assisted extraction of antioxidant compounds with photoprotective effect from palm pressed fiber. The influence of ultrasound intensity and pulse cycle was investigated by means of a central composite rotational design. The optimized condition was ultrasound intensity of 120W.cm(-2) and pulse factor of 0.4, yielding 3.24wt%. Compounds such as fatty acids, β-sitosterol, α-tocopherol, squalene, total phenolics and carotene were identified. The extract presented antioxidant activity towards synthetic (2,2-diphenyl-1-picrylhydrazyl - DPPH, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) - ABTS) and biological radicals (Hydroxyl - OH), besides a sun protection factor of 15...
May 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28069221/effects-of-different-hydrostatic-pressure-on-lesions-in-ex-vivo-bovine-livers-induced-by-high-intensity-focused-ultrasound
#6
Min He, Zhiqiang Zhong, Xing Li, Xiaobo Gong, Zhibiao Wang, Faqi Li
It is well-known that acoustic cavitation associated with the high intensity focused ultrasound (HIFU) treatment often would change the morphology and size of lesions in its treatment. In most studies reported in literature, high ambient hydrostatic pressure was used to suppress the cavitation completely. Investigation of the effects by varying the ambient hydrostatic pressure (Pstat) is still lacking. In this paper, the effects of HIFU on lesions in ex vivo bovine liver specimens under various Pstat are systematically investigated...
May 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28069193/safety-of-ultrasound-guided-high-intensity-focused-ultrasound-ablation-for-diffuse-adenomyosis-a-retrospective-cohort-study
#7
Yujie Feng, Liang Hu, Wenzhi Chen, Rong Zhang, Xi Wang, Jinyun Chen
OBJECTIVES: To evaluate the safety of ultrasound-guided high-intensity focused ultrasound (HIFU) ablation for patients with diffuse adenomyosis. METHODS: This was a retrospective cohort study. The data was collected from 417 symptomatic adenomyosis patients who underwent ultrasound-guided HIFU between January 2012 and December 2015 at 1st Affiliated Hospital of Chongqing Medical University, Chongqing, China. Among them were 260 patients with diffuse adenomyosis (Group D) and 157 patients with focal adenomyosis (Group F)...
May 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28067975/assessment-of-acute-thermal-damage-volumes-in-muscle-using-magnetization-prepared-3d-t2-weighted-imaging-following-mri-guided-high-intensity-focused-ultrasound-therapy
#8
Robert M Staruch, Joris Nofiele, Jamie Walker, Chenchen Bing, Ananth J Madhuranthakam, April Bailey, Young-Sun Kim, Avneesh Chhabra, Dennis Burns, Rajiv Chopra
PURPOSE: To evaluate magnetization-prepared 3D T2 -weighted magnetic resonance imaging (MRI) measurements of acute tissue changes produced during ablative MR high-intensity focused ultrasound (MR-HIFU) exposures. MATERIALS AND METHODS: A clinical MR-HIFU system (3T) was used to generate thermal lesions (n = 24) in the skeletal muscles of three pigs. T1 -weighted, 2D T2 -weighted, and magnetization-prepared 3D T2 -weighted sequences were acquired before and after therapy to evaluate tissue changes following ablation...
January 9, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28063191/salvage-high-intensity-focused-ultrasound-hifu-for-locally-recurrent-prostate-cancer-after-failed-radiation-therapy-multi-institutional-analysis-of-418-patients
#9
Sebastien Crouzet, Andreas Blana, Francois J Murat, Gilles Pasticier, Stephen C W Brown, Giario N Conti, Roman Ganzer, Olivier Chapet, Albert Gelet, Christian G Chaussy, Cary N Robertson, Stefan Thuroff, John F Ward
OBJECTIVE: To report the oncological outcome of Salvage high-intensity focused ultrasound (S-HIFU) for locally recurrent prostate cancer (PCa) following External Beam Radiotherapy (EBRT) from a multicenter database. MATERIALS AND METHODS: This retrospective study comprises patients from 9 centers with local recurrent disease following EBRT treated with S-HIFU from 1995 to 2009. Biochemical free survival rates (BFSR) was based on the "Phoenix" definition (nadir+2)...
January 7, 2017: BJU International
https://www.readbyqxmd.com/read/28062179/effects-of-non-focused-microbubble-enhanced-and-high-intensity-focused-ultrasound-on-hemostasis-in-a-rabbit-model-of-liver-trauma
#10
Da-Wei Zhao, Meng Tian, Jian-Zhong Zou, Yuan-Yi Zheng, Tao Li
Uncontrolled hemorrhage after trauma to the liver can lead to death. The present study compared the effects of non-focused microbubble-enhanced ultrasound and high-intensity focused ultrasound on hepatic hemostasis in the injured liver. Blood perfusion level, serum liver enzyme levels and the aspartate transaminase/alanine transaminase ratio differed between the two types of treatment (all p values < 0.05). Hepatic cells in the microbubble-enhanced ultrasound group exhibited edema and compressed the hepatic sinus and blood vessels in the portal area...
January 3, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/28058731/improved-intercostal-hifu-ablation-using-a-phased-array-transducer-based-on-fermat-s-spiral-and-voronoi-tessellation-a-numerical-evaluation
#11
Pascal Ramaekers, Mario Ries, Chrit T W Moonen, Martijn de Greef
PURPOSE: A major complication for abdominal High Intensity Focused Ultrasound (HIFU) applications is the obstruction of the acoustic beam path by the thoracic cage, which absorbs and reflects the ultrasonic energy leading to undesired overheating of healthy tissues in the pre-focal area. Prior work has investigated the determination of optimized transducer apodization laws, which allow for a reduced rib exposure whilst (partially) restoring focal point intensity through power compensation...
January 6, 2017: Medical Physics
https://www.readbyqxmd.com/read/28050693/technical-success-technique-efficacy-and-complications-of-minimally-invasive-imaging-guided-percutaneous-ablation-procedures-of-breast-cancer-a-systematic-review-and-meta-analysis
#12
Giovanni Mauri, Luca Maria Sconfienza, Lorenzo Carlo Pescatori, Maria Paola Fedeli, Marco Alì, Giovanni Di Leo, Francesco Sardanelli
OBJECTIVES: To systematically review studies concerning imaging-guided minimally-invasive breast cancer treatments. METHODS: An online database search was performed for English-language articles evaluating percutaneous breast cancer ablation. Pooled data and 95% confidence intervals (CIs) were calculated. Technical success, technique efficacy, minor and major complications were analysed, including ablation technique subgroup analysis and effect of tumour size on outcome...
January 3, 2017: European Radiology
https://www.readbyqxmd.com/read/28048774/su-f-j-215-non-thermal-pulsed-high-intensity-focused-ultrasound-therapy-combined-with-5-aminolevulinic-acid-an-in-vivo-pilot-study
#13
B Wang, W He, D Cvetkovic, L Chen, C Ma
PURPOSE: It has recently been shown that non-thermal pulsed high intensity focused ultrasound (pHIFU) has a cell-killing effect. The purpose of the study is to investigate the sonosensitizing effect of 5-Aminolevulinic Acid (5-ALA) in non-thermal pHIFU cancer therapy. METHODS: FaDu human head and neck squamous cell carcinoma cells were injected subcutaneously in the flanks of nude mice. After one to two weeks, the tumors reached the volume of 112 ± 8 mm3 and were assigned randomly into a non-thermal pHIFU group (n=9) and a non-thermal sonodynamic therapy (pHIFU after 5-ALA administration) group (n=7)...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048114/su-f-j-216-mr-guided-non-thermal-pulsed-focused-ultrasound-for-cancer-therapy
#14
C Ma, B Wang, D Cvetkovic, L Chen
PURPOSE: High-intensity focused ultrasound has been investigated for ablative therapy and drug enhancement for gene therapy and chemotherapy. The aim of this work is to explore the feasibility of pulsed focused ultrasound (pFUS) for non-thermal cancer therapy using an in vivo animal model. METHODS: An InSightec ExAblate 2000 with a 1.5T GE MR scanner was used in this study. Suitable ultrasound parameters were investigated to perform non-thermal sonications. LNCaP human prostate tumor cells (106) were injected orthotopically in the prostates of nude mice (n = 16)...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046739/su-f-j-225-histology-study-of-mr-guided-pulsed-focused-ultrasound-on-treatment-of-prostate-cancer-in-vivo
#15
L Chen, D Cvetkovic, X Chen, B Wang, R Gupta, C Ma
PURPOSE: Our previous study demonstrated significant tumor growth delay in the mice treated with pulsed high intensity focused ultrasound (pHIFU). The purpose of this study is to understand the cell killing mechanisms of pHIFU. METHODS: Prostate cancer cells (LNCaP), were grown orthotopically in 17 nude mice. Tumor-bearing mice were treated using pHIFU with an acoustic power of 25W, pulse width 100msec and 300 pulses in one sonication under MR guidance. Mutiple sonications were used to cover the whole tumor volume...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28042085/sequential-hifu-heating-and-nanobubble-encapsulation-provide-efficient-drug-penetration-from-stealth-and-temperature-sensitive-liposomes-in-colon-cancer
#16
Joshua VanOsdol, Kalyani Ektate, Selvarani Ramasamy, Danny Maples, Willie Collins, Jerry Malayer, Ashish Ranjan
Mild hyperthermia generated using high intensity focused ultrasound (HIFU) and microbubbles (MBs) can improve tumor drug delivery from non-thermosensitive liposomes (NTSLs) and low temperature sensitive liposomes (LTSLs). However, MB and HIFU are limited by the half-life of the contrast agent and challenges in accurate control of large volume tumor hyperthermia for longer duration (>30min.). The objectives of this study were to: 1) synthesize and characterized long-circulating echogenic nanobubble encapsulated LTSLs (ELTSLs) and NTSLs (ENTSLs), 2) evaluate in vivo drug release following short duration (~20min each) HIFU treatments administered sequentially over an hour in a large volume of mouse xenograft colon tumor, and 3) determine the impact of the HIFU/nanobubble combination on intratumoral drug distribution...
December 30, 2016: Journal of Controlled Release: Official Journal of the Controlled Release Society
https://www.readbyqxmd.com/read/28033149/partial-gland-ablation-in-the-management-of-prostate-cancer-a-review
#17
Timothy D McClure, Daniel J A Margolis, Jim C Hu
PURPOSE OF REVIEW: The index lesion theory has created a strong interest in partial gland ablation for men with prostate cancer. By only treating the focus of clinically significant disease and avoidance of surrounding periprostatic tissue, one may provide adequate oncologic control with minimal side effects. Accurate identification of the index lesion and effective ablation are critical for satisfactory oncologic outcomes. Herein, we review key ablative techniques used in partial gland ablation...
December 28, 2016: Current Opinion in Urology
https://www.readbyqxmd.com/read/28032342/beam-distortion-due-to-gold-fiducial-markers-during-salvage-high-intensity-focused-ultrasound-in-the-prostate
#18
P S Georgiou, J Jaros, H Payne, C Allen, T T Shah, H U Ahmed, E Gibson, D Barratt, B E Treeby
PURPOSE: High intensity focused ultrasound (HIFU) provides a non-invasive salvage treatment option for patients with recurrence after external beam radiation therapy (EBRT). As part of EBRT the prostate is frequently implanted with permanent flducial markers. To date, the impact of these markers on subsequent HIFU treatment is unknown. The objective of this work was to systematically investigate, using computational simulations, how these flducial markers affect the delivery of HIFU treatment...
December 29, 2016: Medical Physics
https://www.readbyqxmd.com/read/28009150/high-intensity-focused-ultrasound-as-first-line-salvage-therapy-in-prostate-cancer-local-relapse-after-radical-prostatectomy-4-year-follow-up-outcomes
#19
Giuseppe Palermo, Angelo Totaro, Emilio Sacco, Nazario Foschi, Gaetano Gulino, Marco Racioppi, Pierfrancesco Bassi, Francesco Pinto
BACKGROUND: Prostate cancer (PCa) is the most commonly diagnosed malignancy in men and the second leading cause of cancer death in developed countries. Despite the primary treatments, 20-30% of patients experience a recurrence. The main objective of this study was to evaluate the clinical efficacy of salvage high intensity focused ultrasound (HIF U) after radical prostatectomy in terms of biochemical free survival rate (BFSR) and PSA nadir. METHODS: Twenty two patients with local recurrence of Pca after radical prostatectomy underwent HIFU as first-line salvage therapy...
February 2017: Minerva Urologica e Nefrologica, the Italian Journal of Urology and Nephrology
https://www.readbyqxmd.com/read/27997415/high-intensity-focused-ultrasound-for-focal-therapy-reality-or-pitfall
#20
Ariel A Schulman, Kae J Tay, Cary N Robertson, Thomas J Polascik
PURPOSE OF REVIEW: Progress in imaging, fusion software, and ablative modalities has fostered growth of the latest image-guided generation of high-intensity focused ultrasound (HIFU) for focal treatment of prostate cancer. Although early reports are encouraging, important questions remain regarding candidate selection, treatment, and outcomes. We review contemporary considerations for the use of HIFU for focal treatment of primary and radio-recurrent prostate cancer. RECENT FINDINGS: HIFU has been used to treat prostate cancer for over two decades...
December 16, 2016: Current Opinion in Urology
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