Background And Purpose: Thermochromic gel phantoms provide a controlled medium for visual assessment of thermal ablation device performance. However, there are limited studies reporting on the comparative assessment of ablation profiles assessed in thermochromic gel phantoms against those in ex vivo tissue. The objective of this study was to compare microwave ablation zones in a thermochromic tissue-mimicking gel phantom and ex vivo bovine liver and to report on measurements of the temperature-dependent dielectric and thermal properties of the phantom.
View Article and Find Full Text PDFIntroduction: Percutaneous microwave ablation (MWA) is clinically accepted for the treatment of lung tumors and oligometastatic disease. Bronchoscopic MWA is under development and evaluation in the clinical setting. We previously reported on the development of a bronchoscopy-guided MWA system integrated with clinical virtual bronchoscopy and navigation and demonstrated the feasibility of transbronchial MWA, using a maximum power of 60 W at the catheter input.
View Article and Find Full Text PDFIntroduction: Aldosterone-producing adenoma (APA) is the most common cause of endocrine-related hypertension but surgery is not always feasible. Current medical interventions are associated with significant side effects and poor patient compliance. New APA animal models that replicate basic characteristics of APA and give physical and biochemical feedback are needed to test new non-surgical treatment methods, such as image-guided thermal ablation.
View Article and Find Full Text PDFBackground And Purpose: Thermochromic gel phantoms provide a controlled medium for visual assessment of thermal ablation device performance. However, there are limited studies reporting on the comparative assessment of ablation profiles assessed in thermochromic gel phantoms against those in tissue. The objective of this study was to compare microwave ablation zones in a thermochromic tissue mimicking gel phantom and bovine liver, and to report on measurements of the temperature dependent dielectric and thermal properties of the phantom.
View Article and Find Full Text PDFObjectives: To assess the feasibility of monitoring transient evolution of thermal ablation zones with a microwave transmission coefficient-based technique.
Methods: Microwave ablation was performed in ex vivo bovine liver with two 2.45 GHz directional antennas.
Int J Hyperthermia
September 2023
Purpose: To develop a computational model of microwave ablation (MWA) with a thermal accelerant gel and apply the model toward interpreting experimental observations in bovine and porcine liver.
Methods: A 3D coupled electromagnetic-heat transfer model was implemented to characterize thermal profiles within bovine and porcine liver tissue during MWA with the HeatSYNC thermal accelerant. Measured temperature dependent dielectric and thermal properties of the HeatSYNC gel were applied within the model.
Primary aldosteronism is the most common cause of secondary hypertension. The first-line treatment adrenalectomy resects adrenal nodules and adjacent normal tissue, limiting suitability to those who present with unilateral disease. Use of thermal ablation represents an emerging approach as a possible minimally invasive therapy for unilateral and bilateral disease, to target and disrupt hypersecreting aldosterone-producing adenomas, while preserving adjacent normal adrenal cortex.
View Article and Find Full Text PDFThermal therapies are under investigation as part of multi-modality strategies for the treatment of pancreatic cancer. In the present study, we determined the kinetics of thermal injury to pancreatic cancer cells in vitro and evaluated predictive models for thermal injury. Cell viability was measured in two murine pancreatic cancer cell lines (KPC, Pan02) and a normal fibroblast (STO) cell line following in vitro heating in the range 42.
View Article and Find Full Text PDFIntroduction: The medical and social interest in the SARS-CoV-2 infection is currently high. This infection can, in severe cases, be accompanied by a series of complications, such as thromboembolic disease or pulmonary parenchymal haemorrhage.
Case Reports: The paper presents two rare cases of massive intrathoracic haemorrhage caused by pulmonary parenchymal haemorrhage and exacerbated by full anticoagulant treatment of thromboembolic disease.
Purpose: To assess the feasibility of delivering microwave ablation for targeted treatment of aldosterone producing adenomas using image-based computational models.
Methods: We curated an anonymized dataset of diagnostic C-metomidate PET/CT images of 14 patients with aldosterone producing adenomas (APA). A semi-automated approach was developed to segment the APA, adrenal gland, and adjacent organs within 2 cm of the APA boundary.
Introduction: Diaphragmatic rupture is a rare but life-threatening condition that occurs in 0.85% of surgically managed thoracoabdominal injuries. In most cases, the condition is accompanied by associated traumas responsible for poor prognosis.
View Article and Find Full Text PDFPurpose: Bio-effects following thermal treatments are a function of the achieved temperature profile in tissue, which can be estimated across tumor volumes with real-time MRI thermometry (MRIT). Here, we report on expansion of a previously developed small-animal microwave hyperthermia system integrated with MRIT for delivering thermal ablation to subcutaneously implanted tumors in mice.
Methods: Computational models were employed to assess suitability of the 2.
An anterior open bite (AOB) is an occlusal disorder that causes the patient both an aesthetic and functional handicap. The lower third of the face is disproportionately larger. Patients are unable to properly occlude with the anterior part of dental arch and occlusion only happens in the premolar and/or molar regions.
View Article and Find Full Text PDFAim: The aim of this study was to evaluate the utility of selected tumor markers for the detection of lung cancer recurrence during follow-up.
Patients And Methods: The study group consisted of 109 patients and 109 healthy controls. The following biomarkers were selected: Carcinoembryonic antigen; cytokeratin fragment 19; neuron-specific enolase; tissue polypeptide-specific antigen; cytokeratin fragments 8, 18 and 19; insulin-like growth factor 1; pro-gastrin-releasing peptide; and 25-hydroxyvitamin D.
Biomed Phys Eng Express
October 2021
Microwave ablation is under investigation as a minimally-invasive treatment for uterine fibroids. Computational models play a vital role in the development, evaluation and characterization of candidate ablation devices. The temperature-dependent dielectric properties of fibroid tissue are essential for accurate computational modeling.
View Article and Find Full Text PDFType 2 uterine fibroids are challenging to resect surgically as ≥ 50% volume of myoma lies within the myometrium. A hysteroscopic approach for ablating fibroids is minimally-invasive, but places a considerable burden on the operator to accurately place the ablation applicator within the target. We investigated the sensitivity of transcervical microwave ablation outcome with respect to position of the ablation applicator within 1 - 3 cm type 2 fibroids.
View Article and Find Full Text PDFPurpose: Microwave ablation (MWA) is a clinically established modality for treatment of lung tumors. A challenge with existing application of MWA, however, is local tumor progression, potentially due to failure to establish an adequate treatment margin. This study presents a robust simulation-based treatment planning methodology to assist operators in comparatively assessing thermal profiles and likelihood of achieving a specified minimum margin as a function of candidate applied energy parameters.
View Article and Find Full Text PDFCeramic-chromium Hall sensors represent a temperature and radiation resistant alternative to Hall sensors based on semiconductors. Demand for these sensors is presently motivated by the ITER and DEMO nuclear fusion projects. The developed ceramic-chromium Hall sensors were tested up to a temperature of 550 °C and a magnetic field of 14 T.
View Article and Find Full Text PDFThe aim of the study was to compare the prognostic significance of lymph node status of patients with lung cancer analyzed by three different methods: hematoxylin and eosin (H&E), immunohistochemistry of cytokeratin 19 (IHC CK19), and One-Step Nucleic Acid Amplification (OSNA). The clinical relevance of the results was evaluated based on relation to prognosis; the disease-free interval (DFI) and overall survival (OS) were analyzed. During radical surgical treatment, a total of 1426 lymph nodes were obtained from 100 patients, creating 472 groups of nodes (4-5 groups per patient) and examined by H&E, IHC CK19 and OSNA.
View Article and Find Full Text PDFBackground/aim: The lungs are the second most common site of cancer dissemination. The aim of this study was to analyze a cohort of patients operated for pulmonary metastases from colorectal carcinoma over a period of 18 years.
Patients And Methods: In a group of 104 patients, relations were sought between overall survival or disease-free survival and preoperative levels of selected biomarkers, number of metastases and the condition of the intrathoracic lymphatic nodes.
Introduction: Acute early vascular complications are rare, but serious complications after kidney transplantation. They often result in graft loss. For this reason, shortening the diagnostic process is crucial.
View Article and Find Full Text PDFBackground: Percutaneous microwave ablation is clinically used for inoperable lung tumour treatment. Delivery of microwave ablation applicators to tumour sites within lung parenchyma under virtual bronchoscopy guidance may enable ablation with reduced risk of pneumothorax, providing a minimally invasive treatment of early-stage tumours, which are increasingly detected with computed tomography (CT) screening. The objective of this study was to integrate a custom microwave ablation platform, incorporating a flexible applicator, with a clinically established virtual bronchoscopy guidance system, and to assess technical feasibility for safely creating localised thermal ablations in porcine lungs .
View Article and Find Full Text PDFAnnu Int Conf IEEE Eng Med Biol Soc
July 2020
Thermal ablation techniques are increasingly used for the treatment of symptomatic uterine fibroids. Thermal protection of myometrial tissue adjacent to the fibroid from ablation is critical to maximally preserve the uterus. This study presents a bench top experimental setup, using ex vivo bovine muscle as a surrogate tissue, for evaluating collateral thermal damage in tissues during fibroid ablation.
View Article and Find Full Text PDF