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Thermal ablation

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https://www.readbyqxmd.com/read/28549003/noninvasive-thermometry-in-high-intensity-focused-ultrasound-ablation
#1
Yufeng Zhou
High-intensity focused ultrasound (HIFU) is emerging as an effective and promising treatment modality for the formation of coagulative necrosis inside the cancer/tumor noninvasively. To guarantee the efficacy and efficiency of HIFU ablation, the temperature field and consequent thermal dose should be monitored accurately in a high temporal and spatial resolution in real time. However, because of the significant variations of the tissue properties and deep penetration of HIFU beam, especially in the abdominal application, noninvasive thermometry is a very challenging topic, which may hamper the wide acceptance of HIFU by physicians worldwide...
May 25, 2017: Ultrasound Quarterly
https://www.readbyqxmd.com/read/28545303/a-thermoelastic-deformation-model-of-tissue-contraction-during-thermal-ablation
#2
Chang Sub Park, Cong Liu, Sheldon K Hall, Stephen J Payne
PURPOSE: Thermal ablation is an energy-based ablation technique widely used during minimally invasive cancer treatment. Simulations are used to predict the dead tissue post therapy. However, one difficulty with the simulations is accurately predicting the ablation zone in post-procedural images due to the contraction of tissue as a result of exposure to elevated temperatures. MATERIALS AND METHODS: A mathematical model of the thermoelastic deformation for an elastic isotropic material was coupled with a three state thermal denaturation model to determine the contraction of tissue during thermal ablation...
May 25, 2017: International Journal of Hyperthermia
https://www.readbyqxmd.com/read/28544848/decomposition-of-phenolic-impregnated-carbon-ablator-pica-as-a-function-of-temperature-and-heating-rate
#3
Brody Bessire, Timothy K Minton
Material response models for phenolic-based thermal protection systems (TPSs) for atmospheric entry are limited by the lack of knowledge of the nonequilibrium processes that may govern the decomposition pathways of phenolic resin at heating rates up to tens of degrees Celsius per second. We have investigated the pyrolysis of phenolic impregnated carbon ablator (PICA) by measuring the molar yields of the volatile decomposition products as a function of temperature at four nominal heating rates of 3.1, 6.1, 12...
May 25, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28544745/fs-laser-ablation-of-teeth-is-temperature-limited-and-provides-information-about-the-ablated-components
#4
Rebeca Ferraz de Menezes, Catherine Malinda Harvey, Marleny Elizabeth Márquez de Martínez Gerbi, Zachary J Smith, Dan Smith, Juan C Ivaldi, Alton Phillips, James W Chan, Sebastian Wachsmann-Hogiu
The goal of this work is to investigate the thermal effects of femtosecond laser (fs-laser) ablation for the removal of carious dental tissue. Additional studies identify different tooth tissues through femtosecond laser induced breakdown spectroscopy (fsLIBS) for the development of a feedback loop that could be utilized during ablation in a clinical setting. Scanning Election Microscope (SEM) images reveal that minimal morphological damages are incurred at repetition rates below the carbonization threshold of each tooth tissue...
May 24, 2017: Journal of Biophotonics
https://www.readbyqxmd.com/read/28543540/computational-modeling-of-915-mhz-microwave-ablation-comparative-assessment-of-temperature-dependent-tissue-dielectric-models
#5
Garron Deshazer, Mark Hagmann, Derek Merck, Jan Sebek, Kent B Moore, Punit Prakash
PURPOSE: The objective of this study is to develop a computational model for simulating 915 MHz microwave ablation (MWA), and verify the simulation predictions of transient temperature profiles against experimental measurements. Due to the limited experimental data characterizing temperature-dependent changes of tissue dielectric properties at 915 MHz, we comparatively assess two temperature dependent approaches of modeling of dielectric properties: model A- piecewise linear temperature dependencies based on existing, but limited, experimental data, and model B- similar to model A, but augmented with linear decrease in electrical conductivity above 95 °C, as guided by our experimental measurements...
May 23, 2017: Medical Physics
https://www.readbyqxmd.com/read/28541897/capacitive-micro-machined-ultrasound-transducers-for-interstitial-high-intensity-ultrasound-therapies
#6
W Apoutou N'Djin, Bjoern Gerold, Jeremy Vion, Michael Canney, An Nguyen-Dinh, Alexandre Carpentier, Jean-Yves Chapelon
Capacitive Micro-machined Ultrasound Transducers (CMUTs) exhibit several potential advantages over conventional piezo technologies for use in therapeutic ultrasound devices, including: ease of miniaturization and integration with electronics, broad bandwidth (>several MHz), and compatibility with magnetic resonance imaging (MRI). In this work, the electro-acoustic performance of CMUTs designed for interstitial high intensity contact ultrasound (HICU) applications was evaluated and the feasibility of generating ultrasound-induced heating and thermal destruction of biological tissues was studied...
May 24, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28540836/vocal-cord-paresis-following-single-session-high-intensity-focused-ablation-hifu-treatment-of-benign-thyroid-nodules-incidence-and-risk-factors
#7
Brian Hh Lang, Yu-Cho Woo, Keith Wan-Hang Chiu
BACKGROUND: Vocal cord paresis (VCP) may occur following high intensity focused ultrasound (HIFU) of thyroid nodules. We hypothesized its occurrence relates to the distance of the focus point (FP) of the HIFU beams from the recurrent laryngeal nerve (RLN) and the thermal power that this point received. Their relationships were examined. METHODS: One hundred and three patients who underwent HIFU for symptomatic benign thyroid nodule from October 2015 to March 2017 were analyzed...
May 24, 2017: International Journal of Hyperthermia
https://www.readbyqxmd.com/read/28540820/theoretical-model-for-laser-ablation-outcome-predictions-in-brain-calibration-and-validation-on-clinical-mr-thermometry-images
#8
Samuel John Fahrenholtz, Reza Madankan, Shabbar Danish, John D Hazle, R Jason Stafford, David Fuentes
PURPOSE: Neurosurgical laser ablation is experiencing a renaissance. Computational tools for ablation planning aim to further improve the intervention. Here, global optimisation and inverse problems are demonstrated to train a model that predicts maximum laser ablation extent. METHODS: A closed-form steady state model is trained on and then subsequently compared to N = 20 retrospective clinical MR thermometry datasets. Dice similarity coefficient (DSC) is calculated to provide a measure of region overlap between the 57 °C isotherms of the thermometry data and the model-predicted ablation regions; 57 °C is a tissue death surrogate at thermal steady state...
May 19, 2017: International Journal of Hyperthermia
https://www.readbyqxmd.com/read/28540816/numerical-evaluation-of-the-effect-of-electronically-steering-a-phased-array-transducer-axially-post-focal-shifting
#9
Mingjun Wang, Yufeng Zhou
PURPOSE: HIFU has been emerging as an effective and safe modality for the treatment of solid tumours and cancers. The focus shifting range of phased array HIFU transducer is an important safety concern because of the presence of grating lobe in the pre-focal region. However, previous studies were only based on linear acoustic wave model. MATERIALS AND METHODS: The nonlinear wave propagation from a 256-element phased array through multiple layered media was simulated using the angular spectrum approach (ASA) in marching fractional steps with the consideration of diffraction, attenuation and non-linearity effects by a second-order operator splitting scheme...
May 15, 2017: International Journal of Hyperthermia
https://www.readbyqxmd.com/read/28540811/gadolinium-doped-iron-oxide-nanoparticles-induced-magnetic-field-hyperthermia-combined-with-radiotherapy-increases-tumour-response-by-vascular-disruption-and-improved-oxygenation
#10
Pei-Shin Jiang, Hsin-Yu Tsai, Philip Drake, Fu-Nien Wang, Chi-Shiun Chiang
The gadolinium-doped iron oxide nanoparticles (GdIONP) with greater specific power adsorption rate (SAR) than Fe3O4 was developed and its potential application in tumour therapy and particle tracking were demonstrated in transgenic adenocarcinoma of the mouse prostate C1 (TRAMP-C1) tumours. The GdIONPs accumulated in tumour region during the treatment could be clearly tracked and quantified by T2-weighted MR imaging. The therapeutic effects of GdIONP-mediated hyperthermia alone or in combination with radiotherapy (RT) were also evaluated...
May 5, 2017: International Journal of Hyperthermia
https://www.readbyqxmd.com/read/28540805/the-in-vivo-performance-of-a-novel-thermal-accelerant-agent-used-for-augmentation-of-microwave-energy-delivery-within-biologic-tissues-during-image-guided-thermal-ablation-a-porcine-study
#11
William Keun Chan Park, Aaron Wilhelm Palmer Maxwell, Victoria Elizabeth Frank, Michael Patrick Primmer, Jarod Brian Paul, Scott Andrew Collins, Kara Anne Lombardo, Shaolei Lu, Tiffany Marie Borjeson, Grayson Luderman Baird, Damian Edward Dupuy
OBJECTIVES: To investigate the effects of a novel caesium-based thermal accelerant (TA) agent on ablation zone volumes following in vivo microwave ablation of porcine liver and skeletal muscle, and to correlate the effects of TA with target organ perfusion. MATERIALS AND METHODS: This prospective study was performed following institutional animal care and use committee approval. Microwave ablation was performed in liver and resting skeletal muscle in eight Sus scrofa domesticus swine following administration of TA at concentrations of 0 mg/mL (control), 100 mg/mL and 250 mg/mL...
April 24, 2017: International Journal of Hyperthermia
https://www.readbyqxmd.com/read/28540798/pathological-effects-of-lung-radiofrequency-ablation-that-contribute-to-pneumothorax-using-a-porcine-model
#12
Jean Izaaryene, Frederic Cohen, Philippe Souteyrand, Pierre-Henri Rolland, Vincent Vidal, Jean-Michel Bartoli, Veronique Secq, Jean-Yves Gaubert
OBJECTIVES: The incidence of pneumothorax is 7 times higher after lung radiofrequency ablation (RFA) than after lung biopsy. The reasons for such a difference have never been objectified. The histopathologic changes in lung tissue are well-studied and established for RF in the ablation zone. However, it has not been previously described what the nature of thermal injury might be along the shaft of the RF electrode as it traverses through normal lung tissue to reach the ablation zone. The purpose of this study was to determine the changes occurring around the RF needle along the pathway between the ablated zone and the pleura...
April 17, 2017: International Journal of Hyperthermia
https://www.readbyqxmd.com/read/28540789/is-operators-experience-more-important-than-the-ablation-technique-in-image-guided-thermal-ablations
#13
Giovanni Mauri, Luca Maria Sconfienza
No abstract text is available yet for this article.
March 30, 2017: International Journal of Hyperthermia
https://www.readbyqxmd.com/read/28540782/computational-modelling-of-internally-cooled-wet-icw-electrodes-for-radiofrequency-ablation-impact-of-rehydration-thermal-convection-and-electrical-conductivity
#14
Macarena Trujillo, Jose Bon, Enrique Berjano
PURPOSE: (1) To analyse rehydration, thermal convection and increased electrical conductivity as the three phenomena which distinguish the performance of internally cooled electrodes (IC) and internally cooled wet (ICW) electrodes during radiofrequency ablation (RFA), (2) Implement a RFA computer model with an ICW which includes these phenomena and (3) Assess their relative influence on the thermal and electrical tissue response and on the coagulation zone size. METHODS: A 12-min RFA in liver was modelled using an ICW electrode (17 G, 3 cm tip) by an impedance-control pulsing protocol with a constant current of 1...
March 21, 2017: International Journal of Hyperthermia
https://www.readbyqxmd.com/read/28535921/out-of-field-in-vivo-dosimetry-using-tld-in-sabr-for-primary-kidney-cancer-involving-mixed-photon-fields
#15
P Lonski, S Keehan, S Siva, D Pham, R D Franich, M L Taylor, T Kron
PURPOSE: To assess out-of-field dose using three different variants of LiF thermoluminescence dosimeters (TLD) for ten patients who underwent stereotactic ablative body radiotherapy (SABR) for primary renal cell carcinoma (RCC) and compare with treatment planning system (TPS) dose calculations. METHODS AND MATERIALS: Thermoluminescent dosimeter (TLD) measurements were conducted at 20, 30, 40 and 50cm from isocentre on ten patients undergoing SABR for primary RCC...
May 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28532021/nanosecond-laser-ablation-enhances-cellular-infiltration-in-a-hybrid-tissue-scaffold
#16
S Jahnavi, N Arthi, S Pallavi, C Selvaraju, G S Bhuvaneshwar, T V Kumary, R S Verma
Hybrid tissue engineered (HTE) scaffolds constituting polymeric nanofibers and biological tissues have attractive bio-mechanical properties. However, they suffer from small pore size due to dense overlapping nanofibers resulting in poor cellular infiltration. In this study, using nanosecond (ns) laser, we fabricated micro-scale features on Polycaprolactone (PCL)-Chitosan (CH) nanofiber layered bovine pericardium based Bio-Hybrid scaffold to achieve enhanced cellular adhesion and infiltration. The laser energy parameters such as fluence of 25J/cm(2), 0...
August 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28528576/using-non-thermal-irreversible-electroporation-to-create-an-in-vivo-niche-for-exogenous-cell-engraftment
#17
Tammy T Chang, Vivian X Zhou, Boris Rubinsky
The critical shortage of donor organs has spurred investigation of alternative approaches to either generate replacement organs or implant exogenous cells for treatment of end-stage organ failure. Non-thermal irreversible electroporation (NTIRE), which uses brief high electric field pulses to induce irreversible permeabilization of cell membranes, has emerged as a technique for tumor ablation. Here, we introduce a new application for NTIRE that employs in situ cell ablation to create a niche within a solid organ for engraftment of exogenous cells in vivo...
May 1, 2017: BioTechniques
https://www.readbyqxmd.com/read/28527529/image-guided-ablation-of-renal-cell-carcinoma
#18
REVIEW
T M Wah
This review article aims to provide an overview of image-guided ablation of renal cell carcinoma (RCC) since it was first introduced in 1998. This will cover the background and rationale behind its development; an overview of the evidence for current thermal technology, such as heat-based, e.g., radiofrequency ablation (RFA), microwave ablation (MWA), and cold-based energies, e.g., cryoablation used; and summarise the published evidence regarding its treatment efficacy and oncological outcome. In addition, it aims to provide an insight into the potential role of the new non-thermal ablative technology, e...
May 17, 2017: Clinical Radiology
https://www.readbyqxmd.com/read/28526827/activated-hepatic-stellate-cells-secrete-periostin-to-induce-stem-cell-like-phenotype-of-residual-hepatocellular-carcinoma-cells-after-heat-treatment
#19
Rui Zhang, Rong-Rong Yao, Jing-Huan Li, Gang Dong, Min Ma, Qiong-Dan Zheng, Dong-Mei Gao, Jie-Feng Cui, Zheng-Gang Ren, Rong-Xin Chen
Some evidences show that residual tumor after thermal ablation will progress rapidly. However, its mechanisms remain unclear. Here, we assessed whether activated HSCs could regulate stem cell-like property of residual tumor after incomplete thermal ablation to promote tumor progression. Human HCC cell lines were exposed to sublethal heat treatment to simulate the peripheral zone of thermal ablation. After residual HCC cells were cultured with conditional medium (CM) from activated HSCs, parameters of the stem cell-like phenotypes were analyzed...
May 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28523127/high-intensity-focused-ultrasound-hifu-ablation-of-benign-thyroid-nodules-a-systematic-review
#20
REVIEW
Brian Hung-Hin Lang, Arnold L H Wu
BACKGROUND: With an increasing number of imaging studies being done nowadays, the number of incidentally discovered thyroid nodules is expected to rise. Although many of these nodules are small and benign in nature, some do grow and may cause pressure and/or thyrotoxic symptoms. Surgical resection has traditionally been recommended for symptomatic nodules but is associated with risk of hypothyroidism, bleeding, infection, and nerve damage. High intensity focused ultrasound (HIFU) is one of the non-surgical thermal ablation techniques that may serve as an alternative in the treatment of benign thyroid nodules...
2017: Journal of Therapeutic Ultrasound
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