The Experts below are selected from a list of 16689 Experts worldwide ranked by ideXlab platform
Masami Murata - One of the best experts on this subject based on the ideXlab platform.
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planar radiating oscillator using butterfly shaped patch element and spatial power combining array
International Journal of Infrared and Millimeter Waves, 2000Co-Authors: Masami Murata, Akiko Kishi, Shingo Ohmori, Toshiaki MatsuiAbstract:A planar radiating oscillator using a butterfly-shaped patch element is described. To obtain an injection-locking range that can be changed and low cross-polarization, we used a butterfly-shaped patch. The patch element was able to change the injection-locking range while maintaining low cross-polarization, and two types of patch were compared. As one application, we designed and fabricated 1x2, 2x1 and 2x2 spatial power-combining arrays by using radiative mutual coupling. The 2x2 array was successfully operated with a single-Bias Supply without using a 3-D (three-dimensional) Fabry-Perot cavity. An equivalent isotropic radiated power of 2.5 W was measured at X-band.
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2 2 spatial power combining array of planar radiating oscillator using butterfly shaped patch element
European Microwave Conference, 1999Co-Authors: Masami Murata, Toshiaki MatsuiAbstract:A 2 × 2 planar radiating oscillator array using butterfly-shaped patch element is presented. The radiating oscillator element can control the injection-locking range for synchronization. Additionally, the radiating oscillator and its array have technical advantages for operation using single Bias Supply. Equivalent isotropic radiated power 2.5W has been obtained at X-band.
Toshiaki Matsui - One of the best experts on this subject based on the ideXlab platform.
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planar radiating oscillator using butterfly shaped patch element and spatial power combining array
International Journal of Infrared and Millimeter Waves, 2000Co-Authors: Masami Murata, Akiko Kishi, Shingo Ohmori, Toshiaki MatsuiAbstract:A planar radiating oscillator using a butterfly-shaped patch element is described. To obtain an injection-locking range that can be changed and low cross-polarization, we used a butterfly-shaped patch. The patch element was able to change the injection-locking range while maintaining low cross-polarization, and two types of patch were compared. As one application, we designed and fabricated 1x2, 2x1 and 2x2 spatial power-combining arrays by using radiative mutual coupling. The 2x2 array was successfully operated with a single-Bias Supply without using a 3-D (three-dimensional) Fabry-Perot cavity. An equivalent isotropic radiated power of 2.5 W was measured at X-band.
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2 2 spatial power combining array of planar radiating oscillator using butterfly shaped patch element
European Microwave Conference, 1999Co-Authors: Masami Murata, Toshiaki MatsuiAbstract:A 2 × 2 planar radiating oscillator array using butterfly-shaped patch element is presented. The radiating oscillator element can control the injection-locking range for synchronization. Additionally, the radiating oscillator and its array have technical advantages for operation using single Bias Supply. Equivalent isotropic radiated power 2.5W has been obtained at X-band.
Giampiero Tosi - One of the best experts on this subject based on the ideXlab platform.
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real time in vivo dosimetry using micro mosfet detectors during intraoperative electron beam radiation therapy in early stage breast cancer
Radiotherapy and Oncology, 2006Co-Authors: M Ciocca, Valeria Piazzi, Roberta Lazzari, Andrea Vavassori, Alberto Luini, Paolo Veronesi, Viviana Galimberti, Mattia Intra, Andrea Guido, Giampiero TosiAbstract:Purpose: In a previous paper we reported the results of off-line in vivo measurements using radiochromic films in IOERT. In the present study, a further step was made, aiming at the improvement of the effectiveness of in vivo dosimetry, based on a real-time check of the dose. Materials and methods: Entrance dose was determined using micro-MOSFET detectors placed inside a thin, sterile, transparent catheter. The epoxy side of the detector was faced towards the beam to minimize the anisotropy. Each detector was plugged into a Bias Supply (standard sensitivity) and calibrated at 5 Gy using 6 MeV electrons produced by a conventional linac. Detectors were characterized in terms of linearity, precision and dose per pulse dependence. No energy and temperature dependence was found. The sensitivity change of detectors was about 1% per 20 Gy accumulated dose. Correction factors to convert surface to entrance dose were determined for each combination of energy and applicator. From November 2004 to May 2005, in vivo dosimetry was performed on 45 patients affected by early-stage breast cancer, who underwent IOERT to the tumour bed. IOERT was delivered using electrons (4‐10 MeV) at high dose per pulse, produced by either a Novac7 or a Liac mobile linac. Results: The mean ratio between measured and expected dose was 1.006G0.035 (1 SD), in the range 0.92‐1.1. The procedure uncertainty was 3.6%. Micro-MOSFETs appeared suitable for in vivo dosimetry in IOERT, although some unfavourable aspects, like the limited lifetime and the anisotropy with no build-up, were found. Prospectively, a realtime action level (G6%) on dose discrepancy was defined. Conclusions: Excellent agreement between measured and expected doses was found. Real-time in vivo dosimetry appeared feasible, reliable and more effective than the method previously published. q 2005 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and Oncology 78 (2006) 213–216.
P Francescon - One of the best experts on this subject based on the ideXlab platform.
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calibration of a mosfet detection system for 6 mv in vivo dosimetry
International Journal of Radiation Oncology Biology Physics, 1998Co-Authors: Paolo Scalchi, P FrancesconAbstract:Abstract Purpose: Metal oxide semiconductor field-effect transistor (MOSFET) detectors were calibrated to perform in vivo dosimetry during 6-MV treatments, both in normal setup and total body irradiation (TBI) conditions. Methods and Materials: MOSFET water-equivalent depth, dependence of the calibration factors (CFs) on the field sizes, MOSFET orientation, Bias Supply, accumulated dose, incidence angle, temperature, and spoiler-skin distance in TBI setup were investigated. MOSFET reproducibility was verified. The correlation between the water-equivalent midplane depth and the ratio of the exit MOSFET readout divided by the entrance MOSFET readout was studied. MOSFET midplane dosimetry in TBI setup was compared with thermoluminescent dosimetry in an anthropomorphic phantom. By using ionization chamber measurements, the TBI midplane dosimetry was also verified in the presence of cork as a lung substitute. Results: The water-equivalent depth of the MOSFET is about 0.8 mm or 1.8 mm, depending on which sensor side faces the beam. The field size also affects this quantity; Monte Carlo simulations allow driving this behavior by changes in the contaminating electron mean energy. The CFs vary linearly as a function of the square field side, for fields ranging from 5 × 5 to 30 × 30 cm 2 . In TBI setup, varying the spoiler-skin distance between 5 mm and 10 cm affects the CFs within 5%. The MOSFET reproducibility is about 3% (2 SD) for the doses normally delivered to the patients. The effect of the accumulated dose on the sensor response is negligible. For beam incidence ranging from 0° to 90°, the MOSFET response varies within 7%. No monotonic correlation between the sensor response and the temperature is apparent. Good correlation between the water-equivalent midplane depth and the ratio of the exit MOSFET readout divided by the entrance MOSFET readout was found (the correlation coefficient is about 1). The MOSFET midplane dosimetry relevant to the anthropomorphic phantom irradiation is in agreement with TLD dosimetry within 5%. Ionization chamber and MOSFET midplane dosimetry in inhomogeneous phantoms are in agreement within 2%. Conclusion: MOSFET characteristics are suitable for the in vivo dosimetry relevant to 6-MV treatments, both in normal and TBI setup. The TBI midplane dosimetry using MOSFETs is valid also in the presence of the lung, which is the most critical organ, and allows verifying that calculation of the lung attenuator thicknesses based only on the density is not correct. Our MOSFET dosimetry system can be used also to determine the surface dose by using the water-equivalent depth and extrapolation methods. This procedure depends on the field size used.
Akiko Kishi - One of the best experts on this subject based on the ideXlab platform.
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planar radiating oscillator using butterfly shaped patch element and spatial power combining array
International Journal of Infrared and Millimeter Waves, 2000Co-Authors: Masami Murata, Akiko Kishi, Shingo Ohmori, Toshiaki MatsuiAbstract:A planar radiating oscillator using a butterfly-shaped patch element is described. To obtain an injection-locking range that can be changed and low cross-polarization, we used a butterfly-shaped patch. The patch element was able to change the injection-locking range while maintaining low cross-polarization, and two types of patch were compared. As one application, we designed and fabricated 1x2, 2x1 and 2x2 spatial power-combining arrays by using radiative mutual coupling. The 2x2 array was successfully operated with a single-Bias Supply without using a 3-D (three-dimensional) Fabry-Perot cavity. An equivalent isotropic radiated power of 2.5 W was measured at X-band.