Současné diagnostické metody umožňují zachycení malých nádorů ledvin a řada tumorů je zjištěna náhodně při vyšetření z jiné indikace. To zvyšuje počet nízkých stadií nádorů a otevírá prostor pro méně invazivní léčebné techniky, pokud není indikováno aktivní sledování. Mikrovlnná ablace (MWA) je jednou z metod termální ablace, která se v současnosti dostává do popředí zájmu, především pro svou miniinvazivitu, komfort pro pacienta i intervenčního radiologa a dobré výsledky. Cílem tohoto sdělení je shrnutí současných poznatků o MWA, která je jednou z termoablačních metod používaných v terapii malých renálních nádorů. Doporučení uvedená v tomto článku vycházejí z aktuálních guidelines mezinárodních urologických společností a našich zkušeností s touto metodou. Předkládán je souhrn indikačních kritérií a doporučení, která ložiska jsou vhodná a naopak nevhodná pro ošetření MWA a jakým způsobem sledovat pacienty po výkonu.
Current diagnostic methods are capable of detection small kidney tumors, and many of them are found incidentally during imaging for a different indication. This increase the number of low-stage tumors opens the door to less invasive treatment techniques in situations, when active surveillance is not indicated. Microwave ablation (MWA) is one of thermal ablation methods, which is coming to the fore recently. Its advantage is minimal invasiveness, comfort for the patient and the interventional radiologist, and good results. The aim of this article is to summarize current knowledge about MWA in the therapy of small renal tumors. The recommendations given in this article are based on the current guidelines of international urological societies and our own experience with this method. A summary of the indication criteria, recommendations which tumors are suitable and unsuitable for treatment with MWA and how to monitor patients after the procedure are presented.
- Klíčová slova
- Mikrovlnná ablace,
- MeSH
- katetrizační ablace metody MeSH
- lidé MeSH
- mikrovlny * terapeutické užití MeSH
- miniinvazivní chirurgické výkony MeSH
- nádory ledvin * chirurgie diagnostické zobrazování MeSH
- pooperační péče MeSH
- směrnice pro lékařskou praxi jako téma MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
Cílem příspěvku je hodnocení expozice obyvatelstva radiofrekvenčnímu záření emitovanému televizním vysílačem DVB-T2 a dalšími zdroji umístěnými na vrcholu Ještědu z pohledu ochrany veřejného zdraví. Zároveň článek zahrnuje historii, popis uvedených zdrojů a postup zástupců státní správy při výkonu zdravotního dozoru v této oblasti.
The paper aims to evaluate the population's exposure to radiofrequency radiation emitted by the DVB-T2 television transmitter and other sources located on the top of Jested from the perspective of public health protection. At the same time, the article includes history, description of these sources, and the procedure of the state administration representatives in exercising health surveillance in this area.
- MeSH
- dávka záření MeSH
- ionizující záření * MeSH
- lidé MeSH
- limita detekce MeSH
- mikrovlny škodlivé účinky MeSH
- ochrana veřejného zdraví metody MeSH
- pracovní expozice * analýza normy prevence a kontrola MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
- Geografické názvy
- Česká republika MeSH
Dysfunction of the androgen receptor (AR) signalling axis plays a pivotal role in the development and progression of prostate cancer (PCa). Steroidal and non-steroidal AR antagonists can significantly improve the survival of PCa patients by blocking the action of the endogenous ligand through binding to the hormone receptor and preventing its activation. Herein, we report two synthetic strategies, each utilizing the advantages of microwave irradiation, to modify the A-ring of natural androgen 5α-dihydrotestosterone (DHT) with pyridine scaffolds. Treatment of DHT with appropriate Mannich salts led to 1,5-diketones, which were then converted with hydroxylamine to A-ring-fused 6'-substituted pyridines. To extend the compound library with 4',6'-disubstituted analogues, 2-arylidene derivatives of DHT were subjected to ring closure reactions according to the Kröhnke's pyridine synthesis. The crystal structure of a monosubstituted pyridine product was determined by single crystal X-ray diffraction. AR transcriptional activity in a reporter cell line was investigated for all novel A-ring-fused pyridines and a number of previously synthesized DHT-based quinolines were included to the biological study to obtain information about the structure-activity relationship. It was shown that several A-ring-fused quinolines acted as AR antagonists, in comparison with the dual or agonist character of the majority of A-ring-fused pyridines. Derivative 1d (A-ring-fused 6'-methoxyquinoline) was studied in detail and showed to be a low-micromolar AR antagonist (IC50 = 10.5 μM), and it suppressed the viability and proliferation of AR-positive PCa cell lines. Moreover, the candidate compound blocked the AR downstream signalling, induced moderate cell-cycle arrest and showed to bind recombinant AR and to target AR in cells. The binding mode and crucial interactions were described using molecular modelling.
- MeSH
- androgenní receptory metabolismus MeSH
- antagonisté androgenních receptorů farmakologie MeSH
- dihydrotestosteron * farmakologie metabolismus MeSH
- lidé MeSH
- mikrovlny MeSH
- nádorové buněčné linie MeSH
- nádory prostaty * farmakoterapie metabolismus MeSH
- pyridiny farmakologie MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- elektrokardiografie * metody přístrojové vybavení MeSH
- klinické rozhodování MeSH
- lidé MeSH
- mikrovlny MeSH
- Check Tag
- lidé MeSH
Východiska: U některých pacientů, u nichž nelze dosáhnout dostatečné disekce a konzervace tkáně, může dojít k perforaci orgánů sekundárně po termální ablaci, což je vzácná, ale závažná komplikace. Popis případu: U 69letého muže se 20 dní po mikrovlnné ablaci jaterních metastáz kolorektálního karcinomu objevila gastrokutánní píštěl. Kromě kožní vyrážky, lokální citlivosti a výtoku žaludečního obsahu z rány, kam byla umístěna sonda, nebyly přítomny žádné další příznaky ani symptomy. Pacient byl léčen chirurgicky a byla provedena klínovitá resekce žaludku. Pooperační průběh léčby byl bez komplikací. Po 8 měsících pacient podstoupil stejný zákrok pro lokální progresi stejné léze s použitím pulzní mikrovlnné antény a jehly určené k hydrodisekci. Závěr: Gastrokutánní píštěl je vzácnou komplikací mikrovlnné ablace, nicméně adekvátní hydrodisekce může minimalizovat riziko vzniku těchto komplikací. Správná léčba těchto komplikací nevylučuje opětovné použití mikrovlnné ablace.
Background: Organ perforation secondary to thermal ablation is a rare but severe complication that can occur in certain patients, in whom tissue dissection and preservation cannot be adequately achieved. Case description: A 69-year-old man presented with a gastrocutaneous fistula 20 days after a microwave ablation of liver metastases from colorectal cancer. Besides skin rash, local tenderness, and gastric content discharge from a wound where the probe had been placed, no other signs or symptoms were present. The patient was treated surgically, and a wedge-shaped gastric resection was performed. His postoperative course was uneventful. After 8 months, the patient underwent the same procedure for local progression of the same lesion, using a pulsed MW antenna and a dedicated hydrodissection needle, without complications. Conclusions: A gastrocutaneous fistula is a rare complication of microwave ablation. However, adequate hydrodissection can minimize the risk for the development of these complications. Proper treatment of these complications does not preclude repeated usage of microwave ablation in the future.
- MeSH
- ablace metody škodlivé účinky MeSH
- kolorektální nádory * chirurgie komplikace MeSH
- lidé MeSH
- metastázy nádorů MeSH
- mikrovlny škodlivé účinky MeSH
- nádory jater * chirurgie sekundární MeSH
- píštěl žaludku * chirurgie etiologie MeSH
- senioři MeSH
- výsledek terapie MeSH
- žaludek chirurgie patologie MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- Publikační typ
- kazuistiky MeSH
Due to the clinically proven benefit of hyperthermia treatments if added to standard cancer therapies for various tumor sites and the recent development of non-invasive temperature measurements using magnetic resonance systems, the hyperthermia community is convinced that it is a time when even patients with brain tumors could benefit from regional microwave hyperthermia, even if they are the subject of a treatment to a vital organ. The purpose of this study was to numerically analyze the ability to achieve a therapeutically relevant constructive superposition of electromagnetic (EM) waves in the treatment of hyperthermia targets within the brain. We evaluated the effect of the target size and position, operating frequency, and the number of antenna elements forming the phased array applicator on the treatment quality. In total, 10 anatomically realistic 2D human head models were considered, in which 10 circular hyperthermia targets with diameters of 20, 25, and 30 mm were examined. Additionally, applicators with 8, 12, 16, and 24 antenna elements and operating frequencies of 434, 650, 915, and 1150 MHz, respectively, were analyzed. For all scenarios considered (4800 combinations), the EM field distributions of individual antenna elements were calculated and treatment planning was performed. Their quality was evaluated using parameters applied in clinical practice, i.e., target coverage (TC) and the target to hot-spot quotient (THQ). The 12-antenna phased array system operating at 434 MHz was the best candidate among all tested systems for HT treatments of glioblastoma tumors. The 12 antenna elements met all the requirements to cover the entire target area; an additional increase in the number of antenna elements did not have a significant effect on the treatment quality.
PURPOSE: 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 2.45 GHz microwave applicators for delivering ablation to subcutaneous tumor targets in mice. Phantoms and ex-vivo tissues were heated to temperatures in the range 47-67 °C with custom-made microwave applicators for validating MRIT with the proton resonance frequency shift method against fiberoptic thermometry. HAC15 tumors implanted in nude mice (n = 6) were ablated in vivo and monitored with MRIT in multiple planes. One day post ablation, animals were euthanized, and excised tumors were processed for viability assessment. RESULTS: Average absolute error between temperatures from fiberoptic sensors and MRIT was 0.6 °C across all ex-vivo ablations. During in-vivo experiments, tumors with volumes ranging between 5.4-35.9 mm3 (mean 14.2 mm3) were ablated (duration: 103-150 s) to achieve 55 °C at the tumor boundary. Thermal doses ≥240 CEM43 were achieved across 90.7-98.0% of tumor volumes for four cases. Ablations were incomplete for remaining cases, attributed to motion-affected thermometry. Thermal dose-based ablative tumor coverage agreed with viability assessment of excised tumors. CONCLUSIONS: We have developed a system for delivering microwave ablation to subcutaneous tumors in small animals under MRIT guidance and demonstrated its performance in-vivo.
- MeSH
- magnetická rezonanční tomografie metody MeSH
- mikrovlny terapeutické užití MeSH
- myši nahé MeSH
- myši MeSH
- nádory * diagnostické zobrazování chirurgie MeSH
- termometrie * MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
This work aims to synthesize akaganeite nanoparticles (AKNPs) by using microwave and use them to adsorb Congo red dye (CR) from the aqueous solution. The AKNPs with an average particle size of about 50 nm in width and 100 nm in length could be fabricated in 20 min. The effects of pH, CR initial concentration, adsorption time, and adsorbent dosage on the adsorption process were investigated and the artificial neural network (ANN) was used to analyze the adsorption data. The various ANN structures were examined in training the data to find the optimal model. The structure with training function, TRAINLM; adaptation learning function, LARNGDM; transfer function, LOGSIG (in hidden layer) and PURELIN (in output layer); and 10 neutrons in hidden layer having the highest correlation (R2 = 0.996) and the lowest MSE (4.405) is the optimal ANN structure. The consistency between the experimental data and the data predicted by the ANN model showed that the behavior of the adsorption process of CR onto AKNPs under different conditions can be estimated by the ANN model. The adsorption kinetics was studied by fitting the data into pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models. The results showed that the adsorption kinetics obeyed the pseudo-second-order model and governed by several steps. The adsorption isotherms at the different temperatures were studied by fitting the data to Langmuir, Freundlich, and Temkin isotherm models. The R2 obtained from the Langmuir model was above 0.9 and the highest value in three of four temperatures, suggesting that the adsorption isotherms were the best fit to the Langmuir model and the maximum adsorption capacity was estimated to be more than 150 mg/g. Thermodynamic studies suggested that the adsorption of CR onto AKNPs was a spontaneous and endothermic process and physicochemical adsorption. The obtained results indicated the potential application of microwave-synthesize AKNPs for removing organic dyes from aqueous solutions.
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.Objective:To measure the broadband temperature-dependent dielectric properties of uterine fibroids excised during hysterectomy procedures.Methods: The open-ended coaxial probe method was employed for measuring the broadband dielectric properties of freshly excised human uterine fibroid samples (n = 6) obtained from an IRB-approved tissue bank. The dielectric properties (relative permittivity,εr, and effective electrical conductivity,σeff) were evaluated at temperatures ranging from 23 °C-150 °C, over the frequency range of 0.5-6 GHz. Linear piecewise parametrization with respect to temperature and quadratic parametrization with respect to frequency was applied to characterize broadband temperature-dependent dielectric properties of fibroid tissue.Results: The baseline room temperature values ofεrvary from 57.5 ± 5.29 to 44.5 ± 5.77 units andσeffchanges from 0.91 ± 0.19 to 6.02 ± 0.7 S m-1over the frequency range of 0.5-6 GHz. At temperatures close to the water vaporization point,εr, drops considerably i.e. to 12%-14% of its baseline value for all measured frequencies.σeffvalues initially rise till 98 °C and then fall to 11%-13% of their baseline values at 125 °C for frequencies ≤2.45 GHz. Theσefffollows a decreasing trend for frequencies >2.45 GHz and drops to ∼6 % of their baseline room temperature values.Conclusion:The temperature dependent dielectric properties of uterine fibroid tissues over microwave frequency range are reported for the first time in this study. Parametric models of uterine fibroid dielectric properties are also presented for incorporation within computational models of microwave ablation of fibroids.
- MeSH
- elektrická vodivost MeSH
- leiomyom * chirurgie MeSH
- lidé MeSH
- mikrovlny * MeSH
- počítačová simulace MeSH
- teplota MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The use of microwave technology is currently under investigation for non-invasive estimation of glycemia in patients with diabetes. Due to their construction, metamaterial (MTM)-based sensors have the potential to provide higher sensitivity of the phase shift of the S21 parameter (∠S21) to changes in glucose concentration compared to standard microstrip transmission line (MSTL)-based sensors. In this study, a MSTL sensor and three MTM sensors with 5, 7, and 9 MTM unit cells are exposed to liquid phantoms with different dielectric properties mimicking a change in blood glucose concentration from 0 to 14 mmol/L. Numerical models were created for the individual experiments, and the calculated S-parameters show good agreement with experimental results, expressed by the maximum relative error of 8.89% and 0.96% at a frequency of 1.99 GHz for MSTL and MTM sensor with nine unit cells, respectively. MTM sensors with an increasing number of cells show higher sensitivity of 0.62° per mmol/L and unit cell to blood glucose concentration as measured by changes in ∠S21. In accordance with the numerical simulations, the MTM sensor with nine unit cells showed the highest sensitivity of the sensors proposed by us, with an average of 3.66° per mmol/L at a frequency of 1.99 GHz, compared to only 0.48° per mmol/L for the MSTL sensor. The multi-cell MTM sensor has the potential to proceed with evaluation of human blood samples.
- MeSH
- krevní glukóza * MeSH
- lidé MeSH
- mikrovlny MeSH
- monitorování fyziologických funkcí MeSH
- selfmonitoring glykemie * MeSH
- studie proveditelnosti MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
