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Medical & Biological Engineering &... May 2023Microwave ablation (MWA) is a newly developing minimally invasive thermal therapies technology. The ablation region obtained during MWA mainly depends on the type and...
Microwave ablation (MWA) is a newly developing minimally invasive thermal therapies technology. The ablation region obtained during MWA mainly depends on the type and efficiency of the trocar as well as the energy transfer from the generator to the biological tissue. In the present article, a novel trocar for MWA therapies has been proposed. A 3-dimensional tumor-embedded hepatic gland ablated with the novel MWA trocar has been numerically analyzed using finite element method-based software. The novel trocar consists of a flexible dual tine supplied with a microwave power of 15 W at 2.45/6 GHz for an ablation time of 10 min for all the cases. Various combinations of supplied energy and deploying lengths result in tumor ablations ranging from 2.7 to 4 cm in diameter. Supplying energy at high frequency (6 GHz) to the trocar results in ablating tumors (> 4 cm) with spherical ablation region. The novel trocar generated large ablation regions which are 2-3 times bigger than the tumors obtained using existing single-slot non-cooled trocars. This research on novel trocar may help clinicians in treating large size tumors of symmetric and asymmetric shapes by overcoming the problem associated with precise position of trocar into the tissue.
Topics: Humans; Microwaves; Neoplasms; Liver; Radiofrequency Ablation; Surgical Instruments; Catheter Ablation
PubMed: 36680706
DOI: 10.1007/s11517-023-02781-7 -
Journal of the Chinese Medical... Apr 2005Worldwide, hepatocellular carcinoma (HCC) is a common, refractory, malignant tumor. Surgical resection is feasible in only a few patients, because of limited hepatic... (Review)
Review
Worldwide, hepatocellular carcinoma (HCC) is a common, refractory, malignant tumor. Surgical resection is feasible in only a few patients, because of limited hepatic reserve and multifocality of tumors at diagnosis. Percutaneous ablation therapies, including injection of ethanol (PEI) or acetic acid (PAI), radiofrequency ablation (RFA), and microwave coagulation therapy (MCT), have been the major treatments for unresectable HCC in the past decade. PEI is well established for small (<3 cm) HCC, and PAI is equally as effective as PEI, but with fewer treatment sessions. RFA has recently been suggested to have excellent tumor-ablating ability because it produces a fixed and predictable tumor necrosis zone. Although RFA is also effective for medium-sized HCC, the overall complication rate may be higher than previously assumed. MCT is similar to RFA in its clinical application and potential adverse effects. A combination approach using percutaneous ablation therapy and transcatheter arterial embolization was shown to be effective for large HCC. Other approaches, such as injection of hot saline or yttrium-90 microspheres, cryoablation, or interstitial laser photocoagulation, are less often used nowadays. Multimodal, image-guided, tailored therapy, rather than a fixed treatment algorithm, might be more practical for unresectable HCC. In conclusion, although longterm survival is possible in selected patients with HCC, the overall prognosis remains suboptimal, especially in patients with unfavorable tumor characteristics. While newer anti-tumor therapies with improved efficacy are needed, information about a more rational approach to the use of existing therapeutic options may help to enhance treatment strategies for HCC.
Topics: Acetic Acid; Carcinoma, Hepatocellular; Catheter Ablation; Ethanol; Humans; Indicators and Reagents; Liver Neoplasms; Microwaves
PubMed: 15850062
DOI: 10.1016/S1726-4901(09)70239-4 -
World Journal of Urology 1998Possible mechanisms by which transurethral microwave thermotherapy creates an improvement in vodiing parameters are reviewed. The therapy creates coagulation necrosis in... (Review)
Review
Possible mechanisms by which transurethral microwave thermotherapy creates an improvement in vodiing parameters are reviewed. The therapy creates coagulation necrosis in the hyperplastic adenoma, and thus has the potential to create volume reduction, change in the periurethral tissue, and changes in efferent neuromuscular elements and sensory neural elements. Evidence is presented that suggests that several of these mechanisms are likely important, and there is not a singular mechanism of action.
Topics: Diathermy; Humans; Male; Microwaves; Prostatic Hyperplasia; Urethra
PubMed: 12073234
DOI: 10.1007/s003450050031 -
Journal of Endourology Oct 2000The application of heat with curative aim is an old and very well-known principle in medicine. A review of the history of heat use in the treatment of prostatic disease...
The application of heat with curative aim is an old and very well-known principle in medicine. A review of the history of heat use in the treatment of prostatic disease is presented. The article is based on bibliographic research (MEDLINE Search and PubMed) and focuses on treatment of benign prostatic hyperplasia (BPH) since the first clinical documentation of transrectal hyperthermia for this condition. Then, in a chronological sequence, not only the evolution toward thermotherapy but also enhancements of the latest techniques are presented. The new advances in the field of patient selection, indications, and outcome predictors, as well as new trends in treatment are briefly considered.
Topics: History, 20th Century; Humans; Hyperthermia, Induced; Male; Microwaves; Prostatic Hyperplasia
PubMed: 11083401
DOI: 10.1089/end.2000.14.603 -
Annual International Conference of the... Jul 2022Microwave ablation (MWA) is a clinically widespread minimally invasive treatment method for lung tumors. Preoperative planning plays a vital role in MWA therapy....
Microwave ablation (MWA) is a clinically widespread minimally invasive treatment method for lung tumors. Preoperative planning plays a vital role in MWA therapy. However, previous planning methods are far from satisfactory in clinical practice because they only one-sidedly consider the surgical path or energy parameters of an MWA surgery. In this paper, we propose a novel planning model with a computational model of thermal damage to integrally optimize both the surgical path and energy parameters. To ensure the model can be solved in a reasonable time, we elaborate a search space reducing strategy based on clinical constraints. Simulation and ex vivo experimental results were compared with an average mean absolute error of 0.82 K and an average root mean square error of 1.01 K. Our planning model was evaluated on clinical data, and the experimental results demonstrate the effectiveness of our model.
Topics: Computer Simulation; Humans; Lung Neoplasms; Microwaves; Pain Management; Radiofrequency Ablation
PubMed: 36085605
DOI: 10.1109/EMBC48229.2022.9871915 -
Journal of the College of Physicians... Jul 2020To explore the alterations of neutrophil-to-lymphocyte ratio (NLR) as a systemic inflammatory marker after microwave ablation for benign thyroid nodules. Study...
OBJECTIVE
To explore the alterations of neutrophil-to-lymphocyte ratio (NLR) as a systemic inflammatory marker after microwave ablation for benign thyroid nodules. Study Design: A descriptive study.
PLACE AND DURATION OF STUDY
Department of Radiology, Antalya Training and Research Hospital, from December 2018 to June 2019.
METHODOLOGY
Demographic data of the patients, ultrasonographic features of the nodules, thyroid function tests of the patients, leukocyte, neutrophil, lymphocyte values, and thyroid nodule volumes of the patients before and after the procedure were recorded. NLR and volume reduction ratio (VRR %) of 35 patients with thyroid nodules were compared before and after microwave ablation therapy of the thyroid nodules.
RESULTS
The nodule volume decreased from 23.89 ±15.44 cc to 11.57 ±8.65 cc at two months and to 7.79 ±5.74 cc at six months. The VRR% increased from 38.65 ±16.82 to 63.16 ±14.19 at three months and to 68.29 ±11.80 at six months. The mean value of NLR decreased from 2.28 ±0.86 to 1.78 ±0.54. ROC curve analysis suggested that the optimum pre-NLR cut-off point for 50% VRR success was 2.50 with the specifity and sensitivity of 0.67 and 0.50.
CONCLUSION
After ultrasound-guided microwave ablation of benign thyroid module, VRR percentage increased significantly, while the inflammatory marker NLR value decreased. Key Words: Biomarker, Inflammation, Microwaves, Neutrophil-to-lymphocyte ratio, Thyroid nodule.
Topics: Catheter Ablation; Humans; Microwaves; Radiofrequency Ablation; Systemic Inflammatory Response Syndrome; Thyroid Nodule; Treatment Outcome
PubMed: 32811597
DOI: 10.29271/jcpsp.2020.07.694 -
British Medical Bulletin 2007Hyperthermia induced by microwave diathermy raises the temperature of deep tissues from 41 degrees C to 45 degrees C using electromagnetic power. Microwave diathermy is... (Review)
Review
INTRODUCTION
Hyperthermia induced by microwave diathermy raises the temperature of deep tissues from 41 degrees C to 45 degrees C using electromagnetic power. Microwave diathermy is used in the management of superficial tumours with conventional radiotherapy and chemotherapy and, recently, its use has been successfully extended to physical medicine and sports traumatology in Central and Southern Europe.
METHODS
We searched the literature for relevant studies. Most of the published studies in these fields have used 434 and 915 microwave diathermy, as these wavelengths are most effective.
RESULTS
Hyperthermia induced by microwave diathermy into tissue can stimulate repair processes, increase drug activity, allow more efficient relief from pain, help in the removal of toxic wastes, increase tendon extensibility and reduce muscle and joint stiffness. Moreover, hyperthermia induces hyperaemia, improves local tissue drainage, increases metabolic rate and induces alterations in the cell membrane.
CONCLUSIONS
The biological mechanism that regulates the relationship between the thermal dose and the healing process of soft tissues with low or high water content or with low or high blood perfusion is still under study. Microwave diathermy treatment at 434 and 915 MHz can be effective in the short-term management of musculo-skeletal injuries.
Topics: Diathermy; Dose-Response Relationship, Radiation; Humans; Microwaves; Muscles; Musculoskeletal Diseases; Tendon Injuries
PubMed: 17942453
DOI: 10.1093/bmb/ldm020 -
IEEE Transactions on Bio-medical... Sep 2012A preclinical prototype of a transcutaneous thermal therapy system has been developed for the targeted treatment of breast cancer cells using focused microwaves as an...
A preclinical prototype of a transcutaneous thermal therapy system has been developed for the targeted treatment of breast cancer cells using focused microwaves as an adjuvant to radiation, chemotherapy, and high-intensity-focused ultrasound. The prototype system employs a 2-D array of tapered microstrip patch antennas operating at 915 MHz to focus continuous-wave microwave energy transcutaneously into the pendent breast suspended in a coupling medium. Prior imaging studies are used to ascertain the material properties of the breast tissue, and these data are incorporated into a multiphysics model. Time-reversal techniques are employed to find a solution (relative amplitudes and phase) for focusing at a given location. Modeling tests of this time-reversal focusing method have been performed, which demonstrate good targeting accuracy within heterogeneous breast tissue. Experimental results using the laboratory prototype to perform focused heating in tissue-mimicking gelatin phantoms have demonstrated 1.5-cm-diameter focal spot sizes and differential heating at the desired focus sufficient to achieve an antitumor effect confined to the target region.
Topics: Breast Neoplasms; Equipment Design; Female; Humans; Hyperthermia, Induced; Image Processing, Computer-Assisted; Microwaves; Models, Theoretical; Phantoms, Imaging
PubMed: 22614518
DOI: 10.1109/TBME.2012.2199492 -
The Journal of Urology Nov 2001Interstitial microwave thermal therapy is experimental treatment for prostate cancer with the goal of curing disease, while causing fewer complications than standard... (Clinical Trial)
Clinical Trial
PURPOSE
Interstitial microwave thermal therapy is experimental treatment for prostate cancer with the goal of curing disease, while causing fewer complications than standard treatment options. We present a method for delivering interstitial microwave thermal therapy using microwave radiating helical antennae inserted percutaneously under transrectal ultrasound guidance. We report the results of a trial of this method in 25 patients in whom primary external beam radiation therapy had previously failed. This patient group currently has limited curative options that are associated with a high complication rate. However, these recurrent tumors often remain localized to the prostate, and so they may be amenable to localized therapy.
MATERIALS AND METHODS
Patients with proved prostatic adenocarcinoma were candidates for treatment when prostate specific antigen (PSA) was 15 ng./ml. or less and prostate volume was 50 cc. or less. Followup included PSA measurement, digital rectal examination, urinalysis, and documentation of adverse events at 4, 8, 12 and 24 weeks. Sextant biopsy was performed at week 24. The procedure involved the insertion of 5 antennae percutaneously through a modified brachytherapy template. The antenna arrangement was determined based on computer simulated predictions of temperature throughout the prostate. The prostate was dissected away from the rectum by an injection of sterile saline to provide a thermal barrier that protected the rectum from thermal damage. Temperatures were monitored using interstitial mapping thermistor probes that were also inserted through the template. A minimum peripheral target temperature of 55C but less than 70C was maintained for 15 to 20 minutes, while the urethra, rectum and hydrodissection space remained below 42C. The urethra and rectum were actively cooled in addition to hydrodissection.
RESULTS
Peripheral target temperatures of 55C were achieved. The urethra and rectum remained at a safe temperature. The procedure, including setup and treatment, required approximately 2.5 hours of operating room time. At 24 weeks the PSA nadir was 0.5 ng./ml. or less in 52% of patients and 0.51 to 4 ng./ml. was achieved in an additional 40%. The negative biopsy rate at 24 weeks was 64%, assuming that 3 patients lost to followup would have had positive results. No major complications were observed and in most cases minor complications resolved within 3 months.
CONCLUSIONS
Interstitial microwave thermal therapy for prostate cancer was developed to heat the prostate safely to a cytotoxic temperature. Experience with 25 patients in whom external beam radiation therapy for prostate cancer had failed indicates that the treatment is safe. Although our series indicates that this therapy may be effective, further studies and longer followup are required in larger patient groups to confirm the potential role of this therapy as an option for recurrent and primary prostate cancer.
Topics: Aged; Diathermy; Humans; Male; Microwaves; Middle Aged; Prostatic Neoplasms; Treatment Outcome
PubMed: 11586207
DOI: 10.1016/s0022-5347(05)65658-3 -
Contemporary Urology Jul 1992
Review
Topics: Humans; Hyperthermia, Induced; Male; Microwaves; Prostatic Hyperplasia; Treatment Outcome
PubMed: 10150977
DOI: No ID Found