HS Hospital Service SpA

Aprilia, Italy

HS Hospital Service SpA

Aprilia, Italy
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Amabile C.,H.S. Hospital Service SpA | Ahmed M.,Beth Israel Deaconess Medical Center | Solbiati L.,General Hospital of Busto Arsizio | Meloni M.F.,San Gerardo Hospital | And 6 more authors.
International Journal of Hyperthermia | Year: 2016

Purpose: The aim of this study was to compare the performance of a microwave ablation (MWA) apparatus in preclinical and clinical settings. Materials and method: The same commercial 2.45 GHz MWA apparatus was used throughout this study. In total 108 ablations at powers ranging from 20 to 130 W and lasting from 3 to 30 min were obtained on ex vivo bovine liver; 28 ablations at 60 W, 80 W and 100 W lasting 5 and 10 min were then obtained in an in vivo swine model. Finally, 32 hepatocellular carcinomas (HCCs) and 19 liver metastases in 46 patients were treated percutaneously by administering 60 W for either 5 or 10 min. The treatment outcome was characterised in terms of maximum longitudinal and transversal axis of the induced ablation zone. Results: Ex vivo ablation volumes increased linearly with deposited energy (r2 = 0.97), with higher sphericity obtained at lower power for longer ablation times. Larger ablations were obtained on liver metastases compared to HCCs treated with 60 W for 10 min (p < 0.003), as ablation diameters were 4.1 ± 0.6 cm for metastases and 3.7 ± 0.3 cm for HCC, with an average sphericity index of 0.70 ± 0.04. The results on the in vivo swine model at 60 W were substantially smaller than the ex vivo and clinical results (either populations). No statistically significant difference was observed between ex vivo results at 60 W and HCC results (p > 0.08). Conclusions: For the selected MW ablation device, ex vivo data on bovine liver was more predictive of the actual clinical performance on liver malignancies than an in vivo porcine model. Equivalent MW treatments yielded a significantly different response for HCC and metastases at higher deposited energy, suggesting that outcomes are not only device-specific but must also be characterised on a tissue-by-tissue basis. © 2016 Informa UK Limited, trading as Taylor & Francis Group


PubMed | San Gerardo Hospital, General Hospital of Busto Arsizio, H.S. Hospital Service SpA, Beth Israel Deaconess Medical Center and Polytechnic of Milan
Type: Journal Article | Journal: International journal of hyperthermia : the official journal of European Society for Hyperthermic Oncology, North American Hyperthermia Group | Year: 2016

The aim of this study was to compare the performance of a microwave ablation (MWA) apparatus in preclinical and clinical settings.The same commercial 2.45GHz MWA apparatus was used throughout this study. In total 108 ablations at powers ranging from 20 to 130 W and lasting from 3 to 30min were obtained on ex vivo bovine liver; 28 ablations at 60 W, 80 W and 100 W lasting 5 and 10min were then obtained in an in vivo swine model. Finally, 32 hepatocellular carcinomas (HCCs) and 19 liver metastases in 46 patients were treated percutaneously by administering 60 W for either 5 or 10min. The treatment outcome was characterised in terms of maximum longitudinal and transversal axis of the induced ablation zone.Ex vivo ablation volumes increased linearly with deposited energy (rFor the selected MW ablation device, ex vivo data on bovine liver was more predictive of the actual clinical performance on liver malignancies than an in vivo porcine model. Equivalent MW treatments yielded a significantly different response for HCC and metastases at higher deposited energy, suggesting that outcomes are not only device-specific but must also be characterised on a tissue-by-tissue basis.


Farina L.,University of Rome La Sapienza | Weiss N.,Technion IIT | Nissenbaum Y.,Hebrew University of Jerusalem | Cavagnaro M.,University of Rome La Sapienza | And 7 more authors.
International Journal of Hyperthermia | Year: 2014

Results: Overall, substantial shrinkage of 52-74% of initial tissue volume was noted. The shrinkage was non-uniform over time and space, with observed asymmetry favouring the radial (23-43 % range) over the longitudinal (21-29%) direction. Algorithmic relationships for the shrinkage as a function of time were demonstrated. Furthermore, the smallest cubes showed more substantial and faster contraction (28-40% after 1 min), with more considerable volumetric shrinkage (>10%) in muscle than in liver tissue. Additionally, CT imaging demonstrated initial expansion of the tissue volume, lasting in some cases up to 3 min during the microwave ablation procedure, prior to the contraction phenomenon.Conclusions: In addition to an asymmetric substantial shrinkage of the ablated tissue volume, an initial expansion phenomenon occurs during MW ablation. Thus, complex modifications of the tissue close to a radiating antenna will likely need to be taken into account for future methods of real-time ablation monitoring.Purpose: The aim of this study was to characterise changes in tissue volume during image-guided microwave ablation in order to arrive at a more precise determination of the true ablation zone.Materials and methods: The effect of power (20-80 W) and time (1-10 min) on microwave-induced tissue contraction was experimentally evaluated in various-sized cubes of ex vivo liver (10-40 mm ± 2 mm) and muscle (20 and 40 mm ± 2 mm) embedded in agar phantoms (N = 119). Post-ablation linear and volumetric dimensions of the tissue cubes were measured and compared with pre-ablation dimensions. Subsequently, the process of tissue contraction was investigated dynamically during the ablation procedure through real-time X-ray CT scanning. © 2014 Informa UK Ltd.


Farina L.,University of Rome La Sapienza | Amabile C.,HS Hospital Service SpA | Nissenbaum Y.,Hebrew University of Jerusalem | Cavagnaro M.,University of Rome La Sapienza | And 7 more authors.
2015 9th European Conference on Antennas and Propagation, EuCAP 2015 | Year: 2015

Aim of this study was to characterize the changes occurring in tissues undergoing microwave ablation, in order to more accurately predict the actual treated volume. Different experiments were conducted in restricted samples (10-40 mm side cubes) and in large samples of ex-vivo bovine liver, varying the deposited energy (60 W at 2.45 GHz, applied for 1-10 min). A comparison between pre- and post-ablation dimensions was conducted, pointing out a substantial shrinkage, non-uniform over time and space, asymmetrical along the microwave antenna axis and perpendicularly to it. The obtained results show a complex tissue behavior and a correlation between the carbonized area and the contraction phenomenon. © 2015 EurAAP.


Cavagnaro M.,University of Rome La Sapienza | Amabile C.,HS Hospital Service SpA | Bernardi P.,University of Rome La Sapienza | Pisa S.,University of Rome La Sapienza | Tosoratti N.,HS Hospital Service SpA
IEEE Transactions on Biomedical Engineering | Year: 2011

A new coaxial antenna for microwave ablation therapies is proposed. The antenna design includes a miniaturized choke and an arrowhead cap to facilitate antenna insertion into the tissues. Antenna matching and the shape and dimension of the area of ablated tissue (thermal lesion) obtained in ex vivo conditions are evaluated both numerically and experimentally, finding an optimal agreement between numerical and experimental data. Results show that the antenna is well matched, and that it is able to produce a thermal lesion with an average length of 6.5 cm and an average diameter of 4.5 cm in ex vivo bovine liver when irradiates 60 W for 10 min. Finally, the dependence of antenna performances on possible changes in the antennas structure is investigated, finding an optimal stability with respect to manufacturing tolerances and highlighting the fundamental role played by the antennas choke. © 2011 IEEE.


Poggi G.,Institute Of Care Citta Of Pavia | Tosoratti N.,HS Hospital Service SpA | Montagna B.,Institute Of Care Citta Of Pavia | Picchi C.,Institute Of Care Citta Of Pavia
World Journal of Hepatology | Year: 2015

Although surgical resection is still the optimal treatment option for early-stage hepatocellular carcinoma (HCC) in patients with well compensated cirrhosis, thermal ablation techniques provide a valid nonsurgical treatment alternative, thanks to their minimal invasiveness, excellent tolerability and safety profile, proven efficacy in local disease control, virtually unlimited repeatability and cost-effectiveness. Different energy sources are currently employed in clinics as physical agents for percutaneous or intra-surgical thermal ablation of HCC nodules. Among them, radiofrequency (RF) currents are the most used, while microwave ablations (MWA) are becoming increasingly popular. Starting from the 90s', RF ablation (RFA) rapidly became the standard of care in ablation, especially in the treatment of small HCC nodules; however, RFA exhibits substantial performance limitations in the treatment of large lesions and/or tumors located near major heat sinks. MWA, first introduced in the Far Eastern clinical practice in the 80s', showing promising results but also severe limitations in the controllability of the emitted field and in the high amount of power employed for the ablation of large tumors, resulting in a poor coagulative performance and a relatively high complication rate, nowadays shows better results both in terms of treatment controllability and of overall coagulative performance, thanks to the improvement of technology. In this review we provide an extensive and detailed overview of the key physical and technical aspects of MWA and of the currently available systems, and we want to discuss the most relevant published data on MWA treatments of HCC nodules in regard to clinical results and to the type and rate of complications, both in absolute terms and in comparison with RFA. © The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.


Patent
H.S. Hospital Service S.P.A. | Date: 2013-02-18

A microwave device for the ablation of biological tissues including a coaxial antenna, including an internal conductor, surrounded by a layer of dielectric material, an external conductor coaxial to the dielectric metal tip electrically connected to the internal conductor, and a quarter wave impedance transformer including a sleeve made of dielectric material having a proximal end covered with a layer of metal, the metal extending over nearly a quarter wavelength of electromagnetic field in the dielectric at the operating frequency of the device or of odd multiples of the quarter wavelength, the layer of metal material being connected electrically to the external conductor.


Patent
H.S. Hospital Service S.P.A. | Date: 2014-07-31

An antenna for a microwave device for tissue ablation includes a metal cannula inside which there are arranged an external conductor and an internal conductor of the antenna, between which a layer of electrically insulating material is interposed, and a penetrating tip connected to the antenna. The antenna further includes a reinforcing element connected to a distal end of the cannula, the penetrating tip being connected to a distal end of the reinforcing element.

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