scholarly journals The Potential of Adjusting Water Bolus Liquid Properties for Economic and Precise MR Thermometry Guided Radiofrequency Hyperthermia

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2946
Author(s):  
Kemal Sumser ◽  
Gennaro G. Bellizzi ◽  
Gerard C. van Rhoon ◽  
Margarethus M. Paulides
Keyword(s):  
Power Level ◽  
Electromagnetic Properties ◽  
Large Field ◽  
Relaxation Rates ◽  
Rf Power ◽  
Mr Thermometry ◽  
Hyperthermia Treatment ◽  
Mr Guidance ◽  
External Sources ◽  
Radiofrequency Hyperthermia

The potential of MR thermometry (MRT) fostered the development of MRI compatible radiofrequency (RF) hyperthermia devices. Such device integration creates major technological challenges and a crucial point for image quality is the water bolus (WB). The WB is located between the patient body and external sources to both couple electromagnetic energy and to cool the patient skin. However, the WB causes MRT errors and unnecessarily large field of view. In this work, we studied making the WB MRI transparent by an optimal concentration of compounds capable of modifying T 2 * relaxation without an impact on the efficiency of RF heating. Three different T 2 * reducing compounds were investigated, namely CuSO 4 , MnCl 2 , and Fe 3 O 4 . First, electromagnetic properties and T 2 * relaxation rates at 1.5 T were measured. Next, through multi-physics simulations, the predicted effect on the RF-power deposition pattern was evaluated and MRT precision was experimentally assessed. Our results identified 5 mM Fe 3 O 4 solution as optimal since it does not alter the RF-power level needed and improved MRT precision from 0.39 ° C to 0.09 ° C. MnCl 2 showed a similar MRT improvement, but caused unacceptable RF-power losses. We conclude that adding Fe 3 O 4 has significant potential to improve RF hyperthermia treatment monitoring under MR guidance.

Growth of Polycrystalline Silicon films at low Temperature by Remote Plasma CVD

1992 ◽  
Vol 283 ◽  
Author(s):  
Sung Chul Kim ◽  
Kyu Chang Park ◽  
Sung Ki Kim ◽  
Jung Mok Jun ◽  
Jin Jang
Keyword(s):  
Substrate Temperature ◽  
Polycrystalline Silicon ◽  
Volume Fraction ◽  
Power Level ◽  
Chemical Vapour ◽  
Rf Power ◽  
Crystalline Volume Fraction ◽  
Remote Plasma ◽  
Chemical Vapour Deposition Technique ◽  
Polycrystalline Silicon Films

ABSTRACTWe studied the growth of polycrystalline silicon by using remote plasma chemical vapour deposition technique. The effects of RF power and the substrate temperature on the structural properties have been investigated. With increasing the RF power, the crystalline volume fraction and the grain size increase up to 100W, but decrease for the further increase in power level. We obtained the poly-Si with the crystalline volume fraction of about 74 at.% at the substrate temperature of 330°C.

scholarly journals Up gradation of LHCD system for rf power level up to 2MW for SST1

2010 ◽  
Vol 208 ◽  
pp. 012027 ◽  
Author(s):  
P K Sharma ◽  
K K Ambulkar ◽  
P R Parmar ◽  
C G Virani ◽  
A L Thakur ◽  
...  
Keyword(s):  
Power Level ◽  
Rf Power

scholarly journals MR Thermometry Data Correlate with Pathological Response for Soft Tissue Sarcoma of the Lower Extremity in a Single Center Analysis of Prospectively Registered Patients

Cancers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 959 ◽  
Author(s):  
Michaela Unsoeld ◽  
Ulf Lamprecht ◽  
Frank Traub ◽  
Barbara Hermes ◽  
Marcus Scharpf ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Soft Tissue Sarcoma ◽  
Lower Extremity ◽  
Soft Tissue Sarcomas ◽  
Treatment Temperature ◽  
Pathologic Response ◽  
Preoperative Treatment ◽  
Mr Thermometry ◽  
Hyperthermia Treatment ◽  
Reliable Temperature

Background: There is a strong biologic rationale for using locoregional hyperthermia in soft tissue sarcoma and a randomized trial reported significant improvements with hyperthermia. The aim of this study was to describe the opportunities of magnetic resonance (MR)-based thermometry in a cohort of soft tissue sarcoma patients undergoing combined radiotherapy and locoregional hyperthermia. Patients and Methods: For eleven evaluable patients, tumor volume (VTu) and a separate volume for temperature analysis with reliable temperature distribution (Vtherm) were contoured for every hyperthermia treatment (103 therapies). Temperature data were recorded for all tumors and were correlated with clinical features and pathologic response data. Results: Of 48 patients with high-risk soft tissue sarcomas treated with radio(chemo)therapy and locoregional hyperthermia, MR thermometry was possible in 11 (23%) patients. For all patients, the temperature superseded by 90% of VTu (T90(VTu)) and T90 (Vtherm) were in the range of 37–43 °C and 40–45 °C, respectively. Larger tumors tended to reach higher temperatures. For tumors showing a pathologic response in the resection specimen after preoperative treatment, temperature (T90 (Vtherm)) was significantly higher than in tumors without pathologic response. Conclusion: Lower extremity sarcomas undergoing preoperative treatment with locoregional hyperthermia are especially suitable for MR thermometry. MR thermometry is a promising non-invasive way for temperature measurement during locoregional hyperthermia, showing a positive dose-response relationship.

scholarly journals Radiofrequency applicator concepts for simultaneous MR imaging and hyperthermia treatment of glioblastoma multiforme

2017 ◽  
Vol 3 (2) ◽  
pp. 473-477 ◽  
Author(s):  
Eva Oberacker ◽  
Andre Kuehne ◽  
Jacek Nadobny ◽  
Sebastian Zschaeck ◽  
Mirko Weihrauch ◽  
...  
Keyword(s):  
Glioblastoma Multiforme ◽  
Target Volume ◽  
Rf Heating ◽  
Rf Power ◽  
Therapeutic Approaches ◽  
Hyperthermia Treatment ◽  
Large Tumor ◽  
Target Volumes ◽  
Ultrahigh Fields

AbstractGlioblastoma multiforme is the most frequent and most aggressive malignant brain tumor with de facto no long term curation by the use of current multimodal therapeutic approaches. The efficacy of brachytherapy and enhancing interstitial hyperthermia has been demonstrated. RF heating at ultrahigh fields (B0=7.0T, f=298MHz) has the potential of delivering sufficiently large thermal dosage for hyperthermia of relatively large tumor areas. This work focuses on electromagnetic field (EMF) simulations and provides realistic applicator designs tailored for simultaneous RF heating and MRI. Our simulations took advantage of target volumes derived from patient data, and our preliminary results suggest that RF power can be focused to both a small tumor area and a large clinical target volume.

Macro-effects of resputtering due to negative ion bombardment of growing thin films

1993 ◽  
Vol 8 (8) ◽  
pp. 1928-1937 ◽  
Author(s):  
Daniel J. Kester ◽  
Russell Messier
Keyword(s):  
Thin Film ◽  
Film Growth ◽  
Thickness Distribution ◽  
Power Level ◽  
Negative Ions ◽  
Negative Ion ◽  
Complete Suppression ◽  
Film Material ◽  
Rf Power ◽  
Partial Pressures

Bombardment of a growing thin film by negative ions can lead to changes in the film through the process of resputtering. Macro-effects of resputtering (effects on the film thickness) include a slowing of the film growth rate and, in some cases, a complete suppression of the film growth as well as an etching of the substrate materials. To study this result of resputtering, rf-diode sputtering was used to deposit BaTiO3 films under a variety of conditions, varying deposition time, rf-power level, substrate-to-target distance, total gas pressure, and argon, oxygen, and hydrogen partial pressures. The effect resputtering had on the thickness was seen to be a result of the competition between deposition and etching of the thin film material. The relative influence of the various sputtering parameters and the effect each of these has on the thickness distribution were examined. It was found that the greatest influence was system geometry, followed by rf-power level. Various methods of controlling resputtering are discussed.

Multi-antenna RF Ion Source at a High RF Power Level

2009 ◽  
Author(s):  
Y. Oka ◽  
T. Shoji ◽  
O. Kaneko ◽  
Y. Takeiri ◽  
K. Tsumori ◽  
...  
Keyword(s):  
Power Level ◽  
Ion Source ◽  
Rf Power ◽  
Rf Ion Source

scholarly journals Role of Simulations in the Treatment Planning of Radiofrequency Hyperthermia Therapy in Clinics

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Bibin Prasad ◽  
Jung Kyung Kim ◽  
Suzy Kim
Keyword(s):  
Treatment Planning ◽  
Human Anatomy ◽  
Clinical Aspects ◽  
Phase Array ◽  
Clinical Use ◽  
Hyperthermia Treatment ◽  
Tissue Properties ◽  
Hyperthermia Therapy ◽  
Radiofrequency Hyperthermia ◽  
Effective Development

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.

scholarly journals Design and Analysis of Active Metamaterial Modulated by RF Power Level

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ratanak Phon ◽  
Sungjoon Lim
Keyword(s):  
Power Level ◽  
Rf Power
Sign in / Sign up

Export Citation Format

Share Document