Sergio Curto

Erasmus MC | Erasmus MC · Department of Radiotherapy

Background: The success of cancer hyperthermia (HT) treatments is strongly dependent on the temperatures achieved in the tumor and healthy tissues as it correlates with treatment efficacy and safety, respectively. Hyperthermia treatment planning (HTP) simulations have become pivotal for treatment optimization due to the possibility for pretreatment...

The efficacy of a hyperthermia treatment depends on the delivery of well-controlled heating; hence, accurate temperature monitoring is essential for ensuring effective treatment. For deep pelvic hyperthermia, there are no comprehensive and systematic reports on MR thermometry. Moreover, data inclusion generally lacks objective selection criteria le...

Purpose: To compare the size of the coagulation (CZ) and periablational (PZ) zones created with two commercially available devices in clinical use for radiofrequency (RFA) and microwave ablation (MWA), respectively. Methods: Computer models were used to simulate RFA with a 3-cm Cool-tip applicator and MWA with an Amica-Gen applicator. The Arrhen...

Tissue mimicking phantoms are frequently used in hyperthermia applications for device and protocol optimization. Unfortunately, a commonly experienced limitation is that their precise thermal properties are not available. Therefore, in this study, the thermal properties of three currently used QA phantoms for deep hyperthermia are measured with an...

Purpose: Thermal dose-effect relations have demonstrated that clinical effectiveness of hyperthermia would benefit from more controlled heating of the tumor. Hyperthermia treatment planning (HTP) is a potent tool to study strategies enabling target conformal heating, but its accuracy is affected by patient modeling approximations. Homogeneous phant...

Hyperthermia therapy is a potent enhancer of chemotherapy and radiotherapy. In particular, microwave (MW) and radiofrequency (RF) hyperthermia devices provide a variety of heating approaches that can treat most cancers regardless the size. This review introduces the physics of MW/RF hyperthermia, the current state-of-the-art systems for both locali...

Clinical trials have demonstrated the therapeutic benefits of adding radiofrequency (RF) hyperthermia (HT) as an adjuvant to radio-and chemotherapy. However, maximum utilization of these benefits is hampered by the current inability to maintain the temperature within the desired range. RF HT treatment quality is usually monitored by invasive temper...

Introduction: Within the hyperthermia community, consensus exists that clinical outcome of the treatment radiotherapy and/or chemotherapy plus hyperthermia (i.e. elevating tumor temperature to 40 - 44 °C) is related to the applied thermal dose; hence, treatment quality is crucial for the success of prospective multi-institution clinical trials. Cu...

Clinical outcome of hyperthermia depends on the achieved target temperature, therefore target conformal heating is essential. Currently, invasive temperature probe measurements are the gold standard for temperature monitoring, however, they only provide limited sparse data. In contrast, magnetic resonance thermometry (MRT) provides unique capabilit...

Background: Radiofrequency (RF) mild hyperthermia (40 °C–44 °C for 60 minutes) is an effective adjuvant treatment for several types of cancer. To ensure treatment efficacy, quality assurance (QA) is necessary. This study presents the first systematic 3D characterisation of the heating performance of the commonly used Pyrexar BSD2000-3D MR-compatibl...

Purpose: Integrating small-animal experimental hyperthermia instrumentation with magnetic resonance imaging (MRI) affords real-time monitoring of spatial temperature profiles. This study reports on the development and preliminary in vivo characterisation of a 2.45 GHz microwave hyperthermia system for pre-clinical small animal investigations, inte...

Esophageal varices are a significant complication of portal hypertension. Endoscopic variceal ligation (EVL) is one of the clinical standards for treating these varices and preventing their hemorrhage. Limitations of EVL include the risk of stricture formation and postband ulcer bleeding due to the damage caused to the esophageal mucosa, as well as...

The objective of this study was to evaluate microwave heating enhancements offered by iron/iron oxide nanoparticles dispersed within tissue-mimicking media for improving efficacy of microwave thermal therapy. The following dopamine-coated magnetic nanoparticles (MNPs) were considered: 10 and 20 nm diameter spherical core/shell Fe/Fe3O4, 20 nm edge-...

Purpose: Currently available hyperthermia technology is not well suited to treating cancer malignancies in the intact breast. This study investigates a microwave applicator incorporating multiple patch antennas, with the goal of facilitating controllable power deposition profiles for treating lesions at diverse locations within the intact breast. M...

Introduction: Real time monitoring of tissue temperature is a necessity for precise hyperthermia systems in order to ensure the delivered thermal dose is achieved and the temperature profile is within the desired range (~40-45 ºC for 20-90 mins). We have recently reported a hyperthermia system for small-animal investigations integrating a custom 2....

Quality assurance (QA) guidelines are essential to provide uniform execution of clinical trials with uniform quality hyperthermia treatments. This document outlines the requirements for appropriate QA of all current superficial heating equipment including electromagnetic (radiative and capacitive), ultrasound, and infrared heating techniques. Detai...

Design and characterization of a multilayered compact implantable broadband antenna for wireless biotelemetry applications is presented in this paper. The main features of this novel design are miniaturized size, structure that allows integration of electronic circuits of the implantable medical device inside the antenna, and enhanced bandwidth tha...

El objetivo de este trabajo es evaluar la respuesta térmica del tejido mamario a un aplicador de microondas utilizado para el tratamiento del cáncer de mama mediante hipertermia. El dispositivo presentado consta de un array de 4 antenas con un plano de masa semiesférico para poder integrarse en una plataforma similar a un sujetador, con el objetivo...

This study investigates a microwave applicator comprising an antenna array for delivering hyperthermia to tumors in the intact breast. 3D electromagnetic models implemented with computational phantoms of exemplar patients are employed to identify array parameters that have strong potential to meet the desired treatment goal. The applicator includes...

Hyperthermia, moderate heating in the range of 40-45 °C for 20 to 60 minutes, has been clinically employed as an adjuvant for radiation/chemotherapy and is under investigation for precise thermally-mediated delivery of cancer therapeutic agents. Magnetic Resonance Imaging (MRI) facilitates non-invasive, real-time spatial thermometry for monitoring...

Purpose: Microwave ablation (MWA) applicators capable of creating directional heating patterns offer the potential of simplifying treatment of targets in proximity to critical structures and avoiding the need for piercing the tumour volume. This work reports on improved directional MWA antennas with the objectives of minimising device diameter for...

Introduction: Moderate tissue heating is the subject of significant investigation with application to thermally mediated delivery and/or heat-triggered release of therapeutic agents (e.g. drugs, immune stimulatory agents) for treatment of cancer and benign disease. Ultra-high field magnetic resonance imaging (MRI) provides high-resolution (spatial...

The objective of this study was to design a comfortable, compact, wearable and easy-to-manufacture microwave applicator affording conformal thermal therapy of breast tumors. Several configurations of patch antenna arrays operating at 434 and 915 MHz were evaluated in terms of average power absorption (aPA) ratio in target tumors and impedance match...

Purpose: The relationship between microwave ablation system operating frequency and ablation performance is not currently well understood. The objective of this study was to comparatively assess the differences in microwave ablation at 915 MHz and 2.45 GHz. Methods: Analytical expressions for electromagnetic radiation from point sources were use...

Purpose: Currently available microwave hyperthermia systems for breast cancer treatment do not conform to the intact breast and provide limited control of heating patterns, thereby hindering an effective treatment. A compact patch antenna with a flared groundplane that may be integrated within a wearable hyperthermia system for the treatment of the...

A wearable microwave hyperthermia system for treatment of breast cancer is proposed to overcome the limitations of currently available clinical applicators. The applicator incorporates an array of rectangular patch elements and a shared hemispheric conformal groundplane. The energy deposition capabilities of the proposed system are evaluated with p...

To overcome the limitations of currently available clinical hyperthermia systems which are based on rigid waveguide antennas, a wearable microwave hyperthermia system is presented. A light wearable system can improve patient comfort and be located in close proximity to the breast, thereby enhancing energy deposition and reducing power requirements....

Microwave ablation (MWA) is a minimally invasive thermal therapy modality increasingly employed for the treatment of tumors and benign disease. For successful treatment, complete thermal coverage of the tumor and margin of surrounding healthy tissue must be achieved. Currently available interstitial antennas for MWA have cylindrically symmetric rad...

A treatment planning platform for interstitial microwave hyperthermia was developed for practical, free-hand clinical implants. Such implants, consisting of non-parallel, moderately curved antennas with varying insertion depths, are used in HDR brachytherapy for treating locally advanced cancer. Numerical models for commercially available MA251 ant...

Microwave ablation is a minimally invasive modality increasingly being used for thermal treatment of cancer in various organs. During ablation procedures, treatment planning is typically restricted to vendor specifications of expected ablation zone volumes based on experiments in unperfused ex vivo tissues, presuming parallel insertion of antennas....

To overcome the limitations of currently available clinical hyperthermia systems which are based on rigid waveguide antennas, a wearable microwave hyperthermia system is presented. A light wearable system can improve patient comfort and be located in close proximity to the breast, thereby enhancing energy deposition and reducing power requirements....

A novel agent based static state estimation strategy for a specific class of physical systems is proposed. Physical systems, (e.g. smart distribution grid) which are well modeled using decentralized measurements and distributed state-space formulations are considered. In such systems, sensor nodes acting as agents estimate only a subset of states,...

The design and characterization of a compact stacked implantable broadband antenna for medical telemetry applications is reported in this paper. The antenna operates in the 402-405 MHz frequency band, which is approved for medical implant communication services. The electromagnetic modeling is based on the finite-difference time-domain method. The...

This work presents the design of a compact implantable broadband antenna for biotelemetry applications. The antenna was designed to operate in the 402-405 MHz frequency band approved for medical implant communication services. The electromagnetic modelling was based on the finite-difference time-domain method. The proposed antenna was tested inside...

The detuning and impedance mismatching of antennas that are implanted in a simulated human body is reported. The study was carried out using electromagnetic modelling based on the finite difference time domain method and a high-resolution male anatomical model. The implanted antennas operated in the Medical Implant Communication Service band. Maxim...

This study quanti¯es the detuning and impedance mismatch of antennas implanted inside the human body. Maximum frequency shifts caused by variations in the electrical properties of body tissues and di®erent anatomical distributions were derived. The results are relevant to the design of implantable antennas. They indicate the bandwidth enhancement a...

A compact patch applicator designed to enhance targeted energy coupling at 434 MHz is a key enabler for sensitising temperature increments in body regions containing superficial tumours. A detailed finite difference time domain (FDTD) body model is used to explore simulated radio-frequency (RF) coupling and temperature increments for typical clinic...

In an expanding number of worldwide clinical trials, conventional loop, dipole and square-patch antennas perform as external hyperthermia applicators for the adjunct treatment of cancer cells at superficial depths inside the human body. A smaller patch design in very close proximity with various phantom tissue models produces focused specific absor...

Single element loop, dipole and conventional square patch antennas have been used as hyperthermia applicators in the treatment of cancerous human cells at superficial depths inside the body. A smaller novel patch antenna in very close proximity to a phantom tissue model produces an enhanced specific absorption rate pattern without significant frequ...

The design of a miniaturised low-profile efficient hyperthermia applicator is presented. The efficiency is attributed to small size, resilience to detuning and wide bandwidth. The antenna provides a high value of SAR and is well matched to tissue, even at close distances.

The IEEE ultra wideband (UWB) standard includes both a multiple frequency carrier (MB-OFDM) and an impulse spectrum (DS-UWB) method, for which application antennas should be appropriately optimized. Small printed monopoles with outline features that can be defined by a Bezier-spline [1] have good matched impedance performance across the 3.1 - 10.6...

A compact patch antenna working at the 434 MHz ISM frequency band is proposed as an RF-Hyperthermia applicator. The electromagnetic interaction in terms of S11, SAR and E-Field distribution of the antenna with a High Fidelity human body model is investigated. This analysis provides useful information for engineers and clinical staff to develop more...

A comparison is made between a conventional Vivaldi antenna and a spline-shaped end-fire antenna for use in small ultra wideband radar systems. The evaluation places emphasis on the linearity of the input impedance phase and the directivity of the small antennas for low-dispersion spatial selectivity.

While limited in dimensions, the shape of small ultra wideband (UWB) antennas can significantly impact on the required gain pattern stablity and the inherent impulse spreading throughout the bandwidth. The comparative gain performance of a square monopole and two Bezier-spline shaped monopoles (optimised for low insertion losses on small groundplan...

In order to minimize exposure to human tissue, electromagnetic interaction with antennas has benefited from a lot of research since hand-held communication transceivers became widely used consumer products. On the other hand, medical applications have been exploiting the ISM (industrial scientific and medical standard) 434 MHz frequency band for th...

A printed ultra wideband (UWB) antenna suitable for multiband orthogonal frequency division multiplexing (MB-OFDM) UWB is presented in this paper. The proposed antenna covers a wide band from 3.1 GHz to 11.2 GHz. Good performance and low cost production was obtained using FR-4 substrate. An examination of the effects of ground plane dimensions on a...

The electromagnetic interaction between a resonant loop antenna in proximity to biological tissue is examined in terms of field components, wave impedance, return loss, efficiency, and specific absorption rate (SAR). Various loop orientations are investigated with respect to the tissue, in order to provide the best coupling and power deposition int...

A novel compact antenna is proposed as an effective RF-hyperthermia applicator operating at the frequency of 434 MHz. The antenna is a compact circular patch embedded in a narrow annular-ring which has an unequal cross-slot and an annular slot in the ground plane. The size of the proposed antenna is significantly reduced compared with the conventio...

The interaction between the circular loop antenna and human tissue is investigated. Return loss, radiation efficiency and specific absorption rate (SAR) when in proximity to human tissue is evaluated for various loop orientations with respect to the tissue. The simulated internal SAR distribution is shown for various orientations with respect to th...

This thesis deals with the design steps, development and validation of an applicator for radio frequency hyperthermia cancer therapy. An applicator design to enhance targeted energy coupling is a key enabler for preferential temperature increments in tumour regions. A single-element, near-field approach requires a miniaturised solution, that addres...