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A Novel Concept of Transperineal Focused Ultrasound Transducer for Prostate Cancer Local Deep Hyperthermia Treatments. Cancers (Basel) 2022; 15:cancers15010163. [PMID: 36612159 PMCID: PMC9818476 DOI: 10.3390/cancers15010163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/14/2022] [Accepted: 12/21/2022] [Indexed: 12/29/2022] Open
Abstract
Design, embodiment, and experimental study of a novel concept of extracorporeal phased array ultrasound transducer for prostate cancer regional deep hyperthermia treatments using a transperineal acoustic window is presented. An optimized design of hyperthermia applicator was derived from a modelling software where acoustic and thermal fields were computed based on anatomical data. Performance tests have been experimentally conducted on gel phantoms and tissues, under 3T MRI guidance using PRFS thermometry. Feedback controlled hyperthermia (ΔT = 5 °C during 20min) was performed on two ex vivo lamb carcasses with prostate mimicking pelvic tissue, to demonstrate capability of spatio-temporal temperature control and to assess potential risks and side effects. Our optimization approach yielded a therapeutic ultrasound transducer consisting of 192 elements of variable shape and surface, pseudo randomly distributed on 6 columns, using a frequency of 700 kHz. Radius of curvature was 140 mm and active water circulation was included for cooling. The measured focusing capabilities covered a volume of 24 × 50 × 60 mm3. Acoustic coupling of excellent quality was achieved. No interference was detected between sonication and MR acquisitions. On ex vivo experiments the target temperature elevation of 5 °C was reached after 5 min and maintained during another 15 min with the predictive temperature controller showing 0.2 °C accuracy. No significant temperature rise was observed on skin and bonny structures. Reported results represent a promising step toward the implementation of transperineal ultrasound hyperthermia in a pilot study of reirradiation in prostate cancer patients.
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Hyperthermia: A Potential Game-Changer in the Management of Cancers in Low-Middle-Income Group Countries. Cancers (Basel) 2022; 14:cancers14020315. [PMID: 35053479 PMCID: PMC8774274 DOI: 10.3390/cancers14020315] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 12/30/2021] [Accepted: 01/05/2022] [Indexed: 02/04/2023] Open
Abstract
Loco-regional hyperthermia at 40-44 °C is a multifaceted therapeutic modality with the distinct triple advantage of being a potent radiosensitizer, a chemosensitizer and an immunomodulator. Risk difference estimates from pairwise meta-analysis have shown that the local tumour control could be improved by 22.3% (p < 0.001), 22.1% (p < 0.001) and 25.5% (p < 0.001) in recurrent breast cancers, locally advanced cervix cancer (LACC) and locally advanced head and neck cancers, respectively by adding hyperthermia to radiotherapy over radiotherapy alone. Furthermore, thermochemoradiotherapy in LACC have shown to reduce the local failure rates by 10.1% (p = 0.03) and decrease deaths by 5.6% (95% CI: 0.6-11.8%) over chemoradiotherapy alone. As around one-third of the cancer cases in low-middle-income group countries belong to breast, cervix and head and neck regions, hyperthermia could be a potential game-changer and expected to augment the clinical outcomes of these patients in conjunction with radiotherapy and/or chemotherapy. Further, hyperthermia could also be a cost-effective therapeutic modality as the capital costs for setting up a hyperthermia facility is relatively low. Thus, the positive outcomes evident from various phase III randomized trials and meta-analysis with thermoradiotherapy or thermochemoradiotherapy justifies the integration of hyperthermia in the therapeutic armamentarium of clinical management of cancer, especially in low-middle-income group countries.
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Sumser K, Bellizzi GG, Forner R, Drizdal T, Tamames JAH, van Rhoon GC, Paulides MM. Dual-Function MR-Guided Hyperthermia: An Innovative Integrated Approach and Experimental Demonstration of Proof of Principle. IEEE Trans Biomed Eng 2020; 68:712-717. [PMID: 32746075 DOI: 10.1109/tbme.2020.3012734] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Temperature monitoring plays a central role in improving clinical effectiveness of adjuvant hyperthermia. The potential of magnetic resonance thermometry for treatment monitoring purposes led to several MR-guided hyperthermia approaches. However, the proposed solutions were sub-optimal due to technological and intrinsic limitations. These hamper achieving target conformal heating possibilities (applicator limitations) and accurate thermometry (inadequate signal-to-noise-ratio (SNR)). In this work, we studied proof of principle of a dual-function hyperthermia approach based on a coil array (64 MHz, 1.5 T) that is integrated in-between a phased array for heating (434 MHz) for maximum signal receive in order to improve thermometry accuracy. Hereto, we designed and fabricated a superficial hyperthermia mimicking planar array setup to study the most challenging interactions of generic phased-array setups in order to validate the integrated approach. Experiments demonstrated that the setup complies with the superficial hyperthermia guidelines for heating and is able to improve SNR at 2-4 cm depth by 17%, as compared to imaging using the body coil. Hence, the results showed the feasibility of our dual-function MR-guided hyperthermia approach as basis for the development of application specific setups.
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Datta NR, Kok HP, Crezee H, Gaipl US, Bodis S. Integrating Loco-Regional Hyperthermia Into the Current Oncology Practice: SWOT and TOWS Analyses. Front Oncol 2020; 10:819. [PMID: 32596144 PMCID: PMC7303270 DOI: 10.3389/fonc.2020.00819] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 04/27/2020] [Indexed: 12/14/2022] Open
Abstract
Moderate hyperthermia at temperatures between 40 and 44°C is a multifaceted therapeutic modality. It is a potent radiosensitizer, interacts favorably with a host of chemotherapeutic agents, and, in combination with radiotherapy, enforces immunomodulation akin to “in situ tumor vaccination.” By sensitizing hypoxic tumor cells and inhibiting repair of radiotherapy-induced DNA damage, the properties of hyperthermia delivered together with photons might provide a tumor-selective therapeutic advantage analogous to high linear energy transfer (LET) neutrons, but with less normal tissue toxicity. Furthermore, the high LET attributes of hyperthermia thermoradiobiologically are likely to enhance low LET protons; thus, proton thermoradiotherapy would mimic 12C ion therapy. Hyperthermia with radiotherapy and/or chemotherapy substantially improves therapeutic outcomes without enhancing normal tissue morbidities, yielding level I evidence reported in several randomized clinical trials, systematic reviews, and meta-analyses for various tumor sites. Technological advancements in hyperthermia delivery, advancements in hyperthermia treatment planning, online invasive and non-invasive MR-guided thermometry, and adherence to quality assurance guidelines have ensured safe and effective delivery of hyperthermia to the target region. Novel biological modeling permits integration of hyperthermia and radiotherapy treatment plans. Further, hyperthermia along with immune checkpoint inhibitors and DNA damage repair inhibitors could further augment the therapeutic efficacy resulting in synthetic lethality. Additionally, hyperthermia induced by magnetic nanoparticles coupled to selective payloads, namely, tumor-specific radiotheranostics (for both tumor imaging and radionuclide therapy), chemotherapeutic drugs, immunotherapeutic agents, and gene silencing, could provide a comprehensive tumor-specific theranostic modality akin to “magic (nano)bullets.” To get a realistic overview of the strength (S), weakness (W), opportunities (O), and threats (T) of hyperthermia, a SWOT analysis has been undertaken. Additionally, a TOWS analysis categorizes future strategies to facilitate further integration of hyperthermia with the current treatment modalities. These could gainfully accomplish a safe, versatile, and cost-effective enhancement of the existing therapeutic armamentarium to improve outcomes in clinical oncology.
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Affiliation(s)
- Niloy R Datta
- Centre for Radiation Oncology KSA-KSB, Kantonsspital Aarau, Aarau, Switzerland
| | - H Petra Kok
- Department of Radiation Oncology, Cancer Center Amsterdam, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Hans Crezee
- Department of Radiation Oncology, Cancer Center Amsterdam, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Udo S Gaipl
- Department of Radiation Oncology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Stephan Bodis
- Centre for Radiation Oncology KSA-KSB, Kantonsspital Aarau, Aarau, Switzerland
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Eigentler TW, Winter L, Han H, Oberacker E, Kuehne A, Waiczies H, Schmitter S, Boehmert L, Prinz C, Trefna HD, Niendorf T. Wideband Self-Grounded Bow-Tie Antenna for Thermal MR. NMR IN BIOMEDICINE 2020; 33:e4274. [PMID: 32078208 DOI: 10.1002/nbm.4274] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 01/07/2020] [Accepted: 01/27/2020] [Indexed: 06/10/2023]
Abstract
The objective of this study was the design, implementation, evaluation and application of a compact wideband self-grounded bow-tie (SGBT) radiofrequency (RF) antenna building block that supports anatomical proton (1 H) MRI, fluorine (19 F) MRI, MR thermometry and broadband thermal intervention integrated in a whole-body 7.0 T system. Design considerations and optimizations were conducted with numerical electromagnetic field (EMF) simulations to facilitate a broadband thermal intervention frequency of the RF antenna building block. RF transmission (B1+ ) field efficiency and specific absorption rate (SAR) were obtained in a phantom, and the thigh of human voxel models (Ella, Duke) for 1 H and 19 F MRI at 7.0 T. B1+ efficiency simulations were validated with actual flip-angle imaging measurements. The feasibility of thermal intervention was examined by temperature simulations (f = 300, 400 and 500 MHz) in a phantom. The RF heating intervention (Pin = 100 W, t = 120 seconds) was validated experimentally using the proton resonance shift method and fiberoptic probes for temperature monitoring. The applicability of the SGBT RF antenna building block for in vivo 1 H and 19 F MRI was demonstrated for the thigh and forearm of a healthy volunteer. The SGBT RF antenna building block facilitated 19 F and 1 H MRI at 7.0 T as well as broadband thermal intervention (234-561 MHz). For the thigh of the human voxel models, a B1+ efficiency ≥11.8 μT/√kW was achieved at a depth of 50 mm. Temperature simulations and heating experiments in a phantom demonstrated a temperature increase ΔT >7 K at a depth of 10 mm. The compact SGBT antenna building block provides technology for the design of integrated high-density RF applicators and for the study of the role of temperature in (patho-) physiological processes by adding a thermal intervention dimension to an MRI device (Thermal MR).
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Affiliation(s)
- Thomas Wilhelm Eigentler
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- Technische Universität Berlin, Chair of Medical Engineering, Berlin, Germany
| | - Lukas Winter
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig und Berlin, Berlin, Germany
| | - Haopeng Han
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- Institute of Computer Science, Humboldt-Universitätzu Berlin, Berlin, Germany
| | - Eva Oberacker
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | | | | | - Sebastian Schmitter
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig und Berlin, Berlin, Germany
| | - Laura Boehmert
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health (BIH), Berlin, Germany
| | - Christian Prinz
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health (BIH), Berlin, Germany
| | - Hana Dobsicek Trefna
- Department of Electrical Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
- MRI.TOOLS GmbH, Berlin, Germany
- Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité Medical Faculty and the Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
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Paulides M, Dobsicek Trefna H, Curto S, Rodrigues D. Recent technological advancements in radiofrequency- andmicrowave-mediated hyperthermia for enhancing drug delivery. Adv Drug Deliv Rev 2020; 163-164:3-18. [PMID: 32229271 DOI: 10.1016/j.addr.2020.03.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 03/20/2020] [Accepted: 03/24/2020] [Indexed: 12/23/2022]
Abstract
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 localized and regional heating, and recent advancements in hyperthermia treatment guidance using real-time computational simulations and magnetic resonance thermometry. Clinical trials involving RF/MW hyperthermia as adjuvant for chemotherapy are also presented per anatomical site. These studies favor the use of adjuvant hyperthermia since it significantly improves curative and palliative clinical outcomes. The main challenge of hyperthermia is the distribution of state-of-the-art heating systems. Nevertheless, we anticipate that recent technology advances will expand the use of hyperthermia to chemotherapy centers for enhanced drug delivery. These new technologies hold great promise not only for (image-guided) perfusion modulation and sensitization for cytotoxic drugs, but also for local delivery of various compounds using thermosensitive liposomes.
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Role of Simulations in the Treatment Planning of Radiofrequency Hyperthermia Therapy in Clinics. JOURNAL OF ONCOLOGY 2019; 2019:9685476. [PMID: 31558904 PMCID: PMC6735211 DOI: 10.1155/2019/9685476] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 07/20/2019] [Accepted: 07/28/2019] [Indexed: 12/26/2022]
Abstract
Hyperthermia therapy is a treatment modality in which tumor temperatures are elevated to higher temperatures to cause damage to cancerous tissues. Numerical simulations are integral in the development of hyperthermia treatment systems and in clinical treatment planning. In this study, simulations in radiofrequency hyperthermia therapy are reviewed in terms of their technical development and clinical aspects for effective clinical use. This review offers an overview of mathematical models and the importance of tissue properties; locoregional mild hyperthermia therapy, including phantom and realistic human anatomy models; phase array systems; tissue damage; thermal dose analysis; and thermoradiotherapy planning. This review details the improvements in numerical approaches in treatment planning and their application for effective clinical use. Furthermore, the modeling of thermoradiotherapy planning, which can be integrated with radiotherapy to provide combined hyperthermia and radiotherapy treatment planning strategies, are also discussed. This review may contribute to the effective development of thermoradiotherapy planning in clinics.
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Synthesis, functionalization, and nanomedical applications of functional magnetic nanoparticles. CHINESE CHEM LETT 2018. [DOI: 10.1016/j.cclet.2018.08.007] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Curto S, Garcia-Miquel A, Suh M, Vidal N, Lopez-Villegas JM, Prakash P. Design and characterisation of a phased antenna array for intact breast hyperthermia. Int J Hyperthermia 2017; 34:250-260. [PMID: 28605946 DOI: 10.1080/02656736.2017.1337935] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
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. MATERIALS AND METHODS A 3D-computational model was implemented to assess power deposition profiles with 915 MHz applicators incorporating a hemispheric groundplane and configurations of 2, 4, 8, 12, 16 and 20 antennas. Hemispheric breast models of 90 mm and 150 mm diameter were considered, where cuboid target volumes of 10 mm edge length (1 cm3) and 30 mm edge length (27 cm3) were positioned at the centre of the breast, and also located 15 mm from the chest wall. The average power absorption (αPA) ratio expressed as the ratio of the PA in the target volume and in the full breast was evaluated. A 4-antenna proof-of-concept array was fabricated and experimentally evaluated. RESULTS Computational models identified an optimal inter-antenna spacing of 22.5° along the applicator circumference. Applicators with 8 and 12 antennas excited with constant phase presented the highest αPA at centrally located and deep-seated targets, respectively. Experimental measurements with a 4-antenna proof-of-concept array illustrated the potential for electrically steering power deposition profiles by adjusting the relative phase of the signal at antenna inputs. CONCLUSIONS Computational models and experimental results suggest that the proposed applicator may have potential for delivering conformal thermal therapy in the intact breast.
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Affiliation(s)
- Sergio Curto
- a Department of Electrical and Computer Engineering , Kansas State University , Manhattan , KS , USA.,b Department of Radiation Oncology , Erasmus MC Cancer Institute , Rotterdam , The Netherlands
| | | | - Minyoung Suh
- d Department of Textile and Apparel, Technology and Management, College of Textiles , North Carolina State University , Raleigh , NC , USA
| | - Neus Vidal
- c Electronics Department , University of Barcelona , Barcelona , Spain
| | | | - Punit Prakash
- a Department of Electrical and Computer Engineering , Kansas State University , Manhattan , KS , USA
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Formulation, Characterization and Bio-evaluation of Holmium-166 labeled Agglomerated Iron Oxide Nanoparticles for Treatment of Arthritis of Knee Joints. ACTA ACUST UNITED AC 2017. [DOI: 10.1016/j.matpr.2017.04.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Stauffer PR, Vasilchenko IL, Osintsev AM, Rodrigues DB, Bar-Ad V, Hurwitz MD, Kolomiets SA. Tumor bed brachytherapy for locally advanced laryngeal cancer: a feasibility assessment of combination with ferromagnetic hyperthermia. Biomed Phys Eng Express 2016. [DOI: 10.1088/2057-1976/2/5/055002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Paulides MM, Verduijn GM, Van Holthe N. Status quo and directions in deep head and neck hyperthermia. Radiat Oncol 2016; 11:21. [PMID: 26868027 PMCID: PMC4751675 DOI: 10.1186/s13014-016-0588-8] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 01/13/2016] [Indexed: 12/18/2022] Open
Abstract
The benefit of hyperthermia as a potent modifier of radiotherapy has been well established and more recently also the combination with chemotherapy was shown beneficial. Also for head and neck cancer, the impact of hyperthermia has been clinically demonstrated by a number of clinical trials. Unfortunately, the technology applied in these studies provided only limited thermal dose control, and the devices used only allowed treatment of target regions close to the skin. Over the last decade, we developed the technology for deep and controlled hyperthermia that allows treatment of the entire head and neck region. Our strategy involves focused microwave heating combined with 3D patient-specific electromagnetic and thermal simulations for conformal, reproducible and adaptive hyperthermia application. Validation of our strategy has been performed by 3D thermal dose assessment based on invasively placed temperature sensors combined with the 3D patient specific simulations. In this paper, we review the phase III clinical evidence for hyperthermia in head and neck tumors, as well as the heating and dosimetry technology applied in these studies. Next, we describe the development, clinical implementation and validation of 3D guided deep hyperthermia with the HYPERcollar, and its second generation, i.e. the HYPERcollar3D. Lastly, we discuss early clinical results and provide an outlook for this technology.
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Affiliation(s)
| | - Gerda M Verduijn
- Erasmus MC Cancer Institute, Box 5201, 3008AE, Rotterdam, The Netherlands.
| | - Netteke Van Holthe
- Erasmus MC Cancer Institute, Box 5201, 3008AE, Rotterdam, The Netherlands.
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Chakraborty S, Sharma KS, Rajeswari A, Vimalnath KV, Sarma HD, Pandey U, Jagannath, Ningthoujam RS, Vatsa RK, Dash A. Radiolanthanide-loaded agglomerated Fe 3O 4 nanoparticles for possible use in the treatment of arthritis: formulation, characterization and evaluation in rats. J Mater Chem B 2015; 3:5455-5466. [PMID: 32262517 DOI: 10.1039/c5tb00677e] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
This investigation reports the preparation of agglomerated Fe3O4 nanoparticles and evaluation of its utility as a viable carrier in the preparation of radiolanthanides as potential therapeutic agents for the treatment of arthritis. The material was synthesized by a chemical route and characterized by XRD, FT-IR, SEM, EDX and TEM analysis. The surface of agglomerated particle possessed ion pairs (-O-:Na+) after dispersing particles in a NaHCO3 solution at pH = 7 which is conducive for radiolanthanide (*Ln = 90Y, 153Sm, 166Ho, 169Er, 177Lu) loading by replacement of Na+ ions with tripositive radiolanthanide ions. Radiolanthanide-loaded particulates exhibited excellent in vitro stability up to ∼3 half-lives of the respective lanthanide radionuclides when stored in normal saline at 37 °C. The radiochemical purities of the loaded particulates were found to be retained to the extent of >70% after 48 h of storage when challenged by a strong chelator DTPA present at a concentration as high as 5 mM, indicating fairly strong chemical association of lanthanides with agglomerated Fe3O4 nanoparticles. Biodistribution studies of 90Y and 166Ho-loaded particulates carried out after intra-articular injection into one of the knee joints of a normal Wistar rat revealed near-complete retention of the radioactive preparations (>98% of the administered radioactivity) within the joint cavity even after 72 h post injection. This was further confirmed by sequential whole-body radio-luminescence imaging. These experimental results are indicative of the potential use of radiolanthanide-loaded agglomerated Fe3O4 nanoparticles for the treatment of arthritis.
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Affiliation(s)
- Sudipta Chakraborty
- Isotope Production and Applications Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India.
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Numan WC, Hofstetter LW, Kotek G, Bakker JF, Fiveland EW, Houston GC, Kudielka G, Yeo DT, Paulides MM. Exploration of MR-guided head and neck hyperthermia by phantom testing of a modified prototype applicator for use with proton resonance frequency shift thermometry. Int J Hyperthermia 2014; 30:184-91. [DOI: 10.3109/02656736.2014.910615] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Paulides MM, Bakker JF, Hofstetter LW, Numan WCM, Pellicer R, Fiveland EW, Tarasek M, Houston GC, van Rhoon GC, Yeo DTB, Kotek G. Laboratory prototype for experimental validation of MR-guided radiofrequency head and neck hyperthermia. Phys Med Biol 2014; 59:2139-54. [DOI: 10.1088/0031-9155/59/9/2139] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Neufeld E, Szczerba D, Chavannes N, Kuster N. A novel medical image data-based multi-physics simulation platform for computational life sciences. Interface Focus 2014; 3:20120058. [PMID: 24427518 DOI: 10.1098/rsfs.2012.0058] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Simulating and modelling complex biological systems in computational life sciences requires specialized software tools that can perform medical image data-based modelling, jointly visualize the data and computational results, and handle large, complex, realistic and often noisy anatomical models. The required novel solvers must provide the power to model the physics, biology and physiology of living tissue within the full complexity of the human anatomy (e.g. neuronal activity, perfusion and ultrasound propagation). A multi-physics simulation platform satisfying these requirements has been developed for applications including device development and optimization, safety assessment, basic research, and treatment planning. This simulation platform consists of detailed, parametrized anatomical models, a segmentation and meshing tool, a wide range of solvers and optimizers, a framework for the rapid development of specialized and parallelized finite element method solvers, a visualization toolkit-based visualization engine, a Python scripting interface for customized applications, a coupling framework, and more. Core components are cross-platform compatible and use open formats. Several examples of applications are presented: hyperthermia cancer treatment planning, tumour growth modelling, evaluating the magneto-haemodynamic effect as a biomarker and physics-based morphing of anatomical models.
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Affiliation(s)
- Esra Neufeld
- Foundation for Research on Information Technologies in Society (IT'IS) , Zeughausstr. 43, 8004 Zürich , Switzerland
| | - Dominik Szczerba
- Foundation for Research on Information Technologies in Society (IT'IS) , Zeughausstr. 43, 8004 Zürich , Switzerland
| | - Nicolas Chavannes
- Foundation for Research on Information Technologies in Society (IT'IS) , Zeughausstr. 43, 8004 Zürich , Switzerland
| | - Niels Kuster
- Foundation for Research on Information Technologies in Society (IT'IS) , Zeughausstr. 43, 8004 Zürich , Switzerland ; Swiss Federal Institute of Technology (ETH) Zürich , 8092 Zürich , Switzerland
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Togni P, Rijnen Z, Numan WCM, Verhaart RF, Bakker JF, van Rhoon GC, Paulides MM. Electromagnetic redesign of the HYPERcollar applicator: toward improved deep local head-and-neck hyperthermia. Phys Med Biol 2013; 58:5997-6009. [DOI: 10.1088/0031-9155/58/17/5997] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Bardati F, Tognolatti P. Figures of merit and their bounds in radiofrequency heating by phased arrays. Int J Hyperthermia 2013; 29:169-80. [PMID: 23590360 DOI: 10.3109/02656736.2013.784813] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PURPOSE The problem of effective power delivery to a semi-deep target by a phased array has been addressed for application to hyperthermia treatment of some tumours in the thorax. METHODS Three efficiencies have been introduced, which estimate system ability in power transfer from generators to body, from body to tumour, and from generators to tumour. They are formulated in terms of a dissipation matrix and an interference matrix. Bounds to achievable efficiencies are obtained. Further figures of merit have also been introduced. The necessary mathematics has been developed. RESULTS A numerical analysis has been carried out for a partially interdigitated planar array of resonant dipoles. Results show how the new parameters can be exploited for optimal selection of the array's degrees of freedom. CONCLUSION The figures of merit and their bounds allow comparisons between RF heating devices and provide guidelines to phased array design.
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Affiliation(s)
- Fernando Bardati
- Department of Civil Engineering and Computer Science, University of Rome Tor Vergata, Rome, Italy.
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Tao Y, Wang G. Conformal Hyperthermia of Superficial Tumor With Left-Handed Metamaterial Lens Applicator. IEEE Trans Biomed Eng 2012; 59:3525-30. [DOI: 10.1109/tbme.2012.2218108] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Trefná HD, Togni P, Shiee R, Vrba J, Persson M. Design of a wideband multi-channel system for time reversal hyperthermia. Int J Hyperthermia 2012; 28:175-83. [PMID: 22335231 DOI: 10.3109/02656736.2011.641655] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PURPOSE To design and test a wideband multi-channel amplifier system for time reversal (TR) microwave hyperthermia, operating in the frequency range 300 MHz-1 GHz, enabling operation in both pulsed and continuous wave regimes. This is to experimentally verify that adaptation of the heating pattern with respect to tumour size can be realised by varying the operating frequency of the antennas and potentially by using Ultra-wideband (UWB) pulse sequences instead of pure harmonic signals. MATERIALS AND METHODS The proposed system consists of 12 identical channels driven by a common reference signal. The power and phase settings are applied with resolutions of 0.1 W and 0.1°, respectively. Using a calibration procedure, the measured output characteristics of each channel are interpolated using polynomial functions, which are then implemented into a system software algorithm driving the system feedback loop. RESULTS The maximum output power capability of the system varies with frequency, between 90 and 135 W with a relative power error of ± 6%. A phase error in the order of ± 4° has been achieved within the entire frequency band. CONCLUSIONS The developed amplifier system prototype is capable of accurate power and phase delivery, over the entire frequency band of the system. The output power of the present system allows for an experimental verification of a recently developed TR-method on phantoms or animals. The system is suitable for further development for head and neck tumours, breast or extremity applications.
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Affiliation(s)
- Hana Dobšíček Trefná
- Department of Signals and Systems, Chalmers University of Technology, Gothenburg, Sweden.
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Canters RAM, Paulides MM, Franckena MF, van der Zee J, van Rhoon GC. Implementation of treatment planning in the routine clinical procedure of regional hyperthermia treatment of cervical cancer: An overview and the Rotterdam experience. Int J Hyperthermia 2012; 28:570-81. [DOI: 10.3109/02656736.2012.675630] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Vrbova B, Vrba J. MICROWAVE THERMOTHERAPY IN CANCER TREATMENT: EVALUATION OF HOMOGENEITY OF SAR DISTRIBUTION. ACTA ACUST UNITED AC 2012. [DOI: 10.2528/pier12032304] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Laurent S, Dutz S, Häfeli UO, Mahmoudi M. Magnetic fluid hyperthermia: focus on superparamagnetic iron oxide nanoparticles. Adv Colloid Interface Sci 2011; 166:8-23. [PMID: 21601820 DOI: 10.1016/j.cis.2011.04.003] [Citation(s) in RCA: 619] [Impact Index Per Article: 47.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 04/19/2011] [Accepted: 04/19/2011] [Indexed: 11/27/2022]
Abstract
Due to their unique magnetic properties, excellent biocompatibility as well as multi-purpose biomedical potential (e.g., applications in cancer therapy and general drug delivery), superparamagnetic iron oxide nanoparticles (SPIONs) are attracting increasing attention in both pharmaceutical and industrial communities. The precise control of the physiochemical properties of these magnetic systems is crucial for hyperthermia applications, as the induced heat is highly dependent on these properties. In this review, the limitations and recent advances in the development of superparamagnetic iron oxide nanoparticles for hyperthermia are presented.
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De Greef M, Kok HP, Bel A, Crezee J. 3D versus 2D steering in patient anatomies: A comparison using hyperthermia treatment planning. Int J Hyperthermia 2011; 27:74-85. [DOI: 10.3109/02656736.2010.531882] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Dobsícek Trefná H, Vrba J, Persson M. Evaluation of a patch antenna applicator for time reversal hyperthemia. Int J Hyperthermia 2010; 26:185-97. [PMID: 20146572 DOI: 10.3109/02656730903436434] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PURPOSE To describe the design, analysis and evaluation of a new antenna array system for microwave hyperthermia. The proposed antenna array was evaluated by the focusing method based on the time-reversal principle. MATERIALS AND METHODS Power absorption distributions in a cylindrical homogeneous and inhomogeneous phantom were calculated for the frequency range 500-900 MHz. Two set-ups with 12 and 16 antennas were analysed by comparing the changes in focusing areas enclosed by the 50%, 75% and 90% iso-SAR contours. For a more quantitative evaluation of the results the average power absorption ratio and remaining tissue maximum index were calculated. RESULTS The sharpest focusing area in the centre of the phantom, 151 mm(2) (9 x 20 mm) (90% iso-SAR), was obtained by using 16 antennas at frequency 900 MHz. The largest focusing area of 280 mm(2) (13 x 24 mm) (90% iso-SAR) was obtained by using 16 antennas at 500 MHz. The SAR focus was steered in the desired radial direction obtaining a 43 mm(2) 90% iso-SAR focus-width in a semi-three-dimensional neck phantom. The results showed qualitative agreement between three dimensions (3D) and two dimensions (2D) for the performance indicators. CONCLUSIONS The conducted study confirms the feasibility of the time-reversal-based focusing methods for microwave hyperthermia. The proposed system shows promise and is suitable for further development in the treatment of head and neck tumours, and extremities application.
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Affiliation(s)
- Hana Dobsícek Trefná
- Department of Signals and Systems, Chalmers University of Technology, Gothenburg, Sweden.
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Paulides MM, Bakker JF, Linthorst M, van der Zee J, Rijnen Z, Neufeld E, Pattynama PMT, Jansen PP, Levendag PC, van Rhoon GC. The clinical feasibility of deep hyperthermia treatment in the head and neck: new challenges for positioning and temperature measurement. Phys Med Biol 2010; 55:2465-80. [PMID: 20371911 DOI: 10.1088/0031-9155/55/9/003] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
To apply high-quality hyperthermia treatment to tumours at deep locations in the head and neck (H&N), we have designed and built a site-specific phased-array applicator. Earlier, we demonstrated its features in parameter studies, validated those by phantom measurements and clinically introduced the system. In this paper we will critically review our first clinical experiences and demonstrate the pivotal role of hyperthermia treatment planning (HTP). Three representative patient cases (thyroid, oropharynx and nasal cavity) are selected and discussed. Treatment planning, the treatment, interstitially measured temperatures and their interrelation are analysed from a physics point of view. Treatments lasting 1 h were feasible and well tolerated and no acute treatment-related toxicity has been observed. Maximum temperatures measured are in the range of those obtained during deep hyperthermia treatments in the pelvic region but mean temperatures are still to be improved. Further, we found that simulated power absorption correlated well with measured temperatures illustrating the validity of our treatment approach of using energy profile optimizations to arrive at higher temperatures. This is the first data proving that focussed heating of tumours in the H&N is feasible. Further, HTP proved a valuable tool in treatment optimization. Items to improve are (1) the transfer of HTP settings into the clinic and (2) the registration of the thermal dose, i.e. dosimetry.
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Affiliation(s)
- M M Paulides
- Department of Radiation Oncology, Erasmus MC-Daniel den Hoed Cancer Center, Rotterdam, The Netherlands.
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de Bruijne M, Wielheesen DHM, van der Zee J, Chavannes N, van Rhoon GC. Benefits of superficial hyperthermia treatment planning: Five case studies. Int J Hyperthermia 2010; 23:417-29. [PMID: 17701533 DOI: 10.1080/02656730701502077] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
PURPOSE To demonstrate the benefits of treatment planning in superficial hyperthermia. MATERIALS AND METHODS Five patient cases are presented, in which treatment planning was applied to troubleshoot treatment-limiting hotspots, to select the optimum applicator type and orientation, to assess the risk associated with metallic implants, to assess the feasibility of heating a deeper seated tumour, and to analyse the effective SAR coverage resulting from arrays of multiple incoherent applicators. FDTD simulation tools were used to investigate treatment options, either based on segmented or simplified anatomies. RESULTS The background, approach and model implementation are presented per case. SAR cross-sections, profiles and isosurfaces are visualized to predict the effective SAR coverage of the target and the location of the maximum power absorption. In addition, the followed treatment strategy and the implications for the clinical treatment are given: for example, higher temperatures, relief of treatment limiting hot-spots or increased power input. CONCLUSIONS Treatment planning in superficial hyperthermia can be applied to improve clinical routine. Its application supports the selection of the optimum technique in non-standard cases, leading to direct benefits for the patient. In addition, treatment planning has shown to be an excellent tool for education and training for hyperthermia technicians and physicians.
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Affiliation(s)
- M de Bruijne
- Hyperthermia Unit, Department of Radiation Oncology, Erasmus Medical Center - Daniel den Hoed Cancer Center, Rotterdam, The Netherlands.
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Franckena M, Canters R, Termorshuizen F, Van Der Zee J, Van Rhoon G. Clinical implementation of hyperthermia treatment planning guided steering: A cross over trial to assess its current contribution to treatment quality. Int J Hyperthermia 2010; 26:145-57. [DOI: 10.3109/02656730903453538] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Chen X, Diederich CJ, Wootton JH, Pouliot J, Hsu IC. Optimisation-based thermal treatment planning for catheter-based ultrasound hyperthermia. Int J Hyperthermia 2010; 26:39-55. [DOI: 10.3109/02656730903341332] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Canters RAM, Wust P, Bakker JF, Van Rhoon GC. A literature survey on indicators for characterisation and optimisation of SAR distributions in deep hyperthermia, a plea for standardisation. Int J Hyperthermia 2010; 25:593-608. [PMID: 19848621 DOI: 10.3109/02656730903110539] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PURPOSE To evaluate the predictive value of SAR indicators by assessing the correlation of a SAR indicator with the corresponding predicted temperature. Ultimately, this should lead to a number of verified SAR indicators for characterization and optimization of a predicted SAR distribution. METHODS A literature survey is followed by an evaluation of the SAR indicators on their functionality, using a set of heuristic classification criteria. To obtain an objective assessment of the predictive value for SAR characterisation, all SAR indicators are evaluated by correlating the value of the SAR indicator to the predicted target temperature when heated with the BSD2000 Sigma 60 applicator. Two methods were followed. First, the specificity of the SAR indicator to target temperature was assessed for each of the 36 patient-specific models, using 30 randomly chosen phase and amplitude settings. Secondly, each SAR indicator was used as a goal function to assess its suitability for optimisation purposes. RESULTS Only a selected number of SAR indicators correlate well with tumour/target-temperature. Hence, for target-related properties, an adequate set of SAR indicators is found in the literature. For hotspots, modifications are desirable. For optimisation purposes, improved objective functions have been defined. CONCLUSIONS From the correlation of the SAR indicators with tumour temperature, a preferred set of SAR indicators is derived: For target heating, 'average SAR ratio', 'Hotspot-target SAR ratio', and 'homogeneity coefficient' provide suitable objective criteria, while for hotspot reduction, 'Hotspot-target SAR ratio' is considered the most useful indicator. For optimisation procedures, 'Hotspot-target SAR ratio' is currently the most suitable objective function.
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Affiliation(s)
- R A M Canters
- Erasmus Medical Center, Radiation Oncology Department, Hyperthermia Unit, Rotterdam, The Netherlands.
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Wang G, Gong Y. Metamaterial lens applicator for microwave hyperthermia of breast cancer. Int J Hyperthermia 2009; 25:434-45. [DOI: 10.1080/02656730903061609] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Paulides MM, Bakker JF, Neufeld E, Zee JVD, Jansen PP, Levendag PC, van Rhoon GC. The HYPERcollar: A novel applicator for hyperthermia in the head and neck. Int J Hyperthermia 2009; 23:567-76. [DOI: 10.1080/02656730701670478] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Bakker JF, Paulides MM, Obdeijn IM, van Rhoon GC, van Dongen KWA. An ultrasound cylindrical phased array for deep heating in the breast: theoretical design using heterogeneous models. Phys Med Biol 2009; 54:3201-15. [DOI: 10.1088/0031-9155/54/10/016] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Hand JW. Modelling the interaction of electromagnetic fields (10 MHz–10 GHz) with the human body: methods and applications. Phys Med Biol 2008; 53:R243-86. [DOI: 10.1088/0031-9155/53/16/r01] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Laurent S, Forge D, Port M, Roch A, Robic C, Vander Elst L, Muller RN. Magnetic iron oxide nanoparticles: synthesis, stabilization, vectorization, physicochemical characterizations, and biological applications. Chem Rev 2008; 108:2064-110. [PMID: 18543879 DOI: 10.1021/cr068445e] [Citation(s) in RCA: 3462] [Impact Index Per Article: 216.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Sophie Laurent
- Department of General, Organic, and Biomedical Chemistry, NMR and Molecular Imaging Laboratory, University of Mons-Hainaut, B-7000 Mons, Belgium
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Paulides MM, Bakker JF, Chavannes N, Van Rhoon GC. A Patch Antenna Design for Application in a Phased-Array Head and Neck Hyperthermia Applicator. IEEE Trans Biomed Eng 2007; 54:2057-63. [DOI: 10.1109/tbme.2007.895111] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Paulides MM, Bakker JF, van Rhoon GC. Electromagnetic Head-And-Neck Hyperthermia Applicator: Experimental Phantom Verification and FDTD Model. Int J Radiat Oncol Biol Phys 2007; 68:612-20. [PMID: 17418965 DOI: 10.1016/j.ijrobp.2007.01.035] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2006] [Revised: 01/08/2007] [Accepted: 01/08/2007] [Indexed: 11/28/2022]
Abstract
PURPOSE To experimentally verify the feasibility of focused heating in the neck region by an array of two rings of six electromagnetic antennas. We also measured the dynamic specific absorption rate (SAR) steering possibilities of this setup and compared these SAR patterns to simulations. METHODS AND MATERIALS Using a specially constructed laboratory prototype head-and-neck applicator, including a neck-mimicking cylindrical muscle phantom, we performed SAR measurements by electric field, Schottky-diode sheet measurements and, using the power-pulse technique, by fiberoptic thermometry and infrared thermography. Using phase steering, we also steered the SAR distribution in radial and axial directions. All measured distributions were compared with the predictions by a finite-difference time-domain-based electromagnetic simulator. RESULTS A central 50% iso-SAR focus of 35 +/- 3 mm in diameter and about 100 +/- 15 mm in length was obtained for all investigated settings. Furthermore, this SAR focus could be steered toward the desired location in the radial and axial directions with an accuracy of approximately 5 mm. The SAR distributions as measured by all three experimental methods were well predicted by the simulations. CONCLUSION The results of our study have shown that focused heating in the neck is feasible and that this focus can be effectively steered in the radial and axial directions. For quality assurance measurements, we believe that the Schottky-diode sheet provides the best compromise among effort, speed, and accuracy, although a more specific and improved design is warranted.
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Affiliation(s)
- Margarethus M Paulides
- Department of Radiation Oncology, Section of Hyperthermia, Daniel den Hoed Cancer Center, Erasmus Medical Center, Rotterdam, The Netherlands.
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