High Voltage Direct Current (HVDC) transmission has been expanding due to rapid development of power electronics technology and by the need for connection of offshore/remote wind farms and large hydro power generators. An HVDC grid will be required to operate the healthy lines continuously, even if a voltage collapse occurs at the remote end. Rapid fault clearing is essential for DC Circuit Breaker (DCCB) even though the requirement varies depending on DC transmission system configurations, Voltage Source Converter (VSC) design, transmission capacity, and DC reactor connected in series with the line/cable, etc. In this paper, the requirements for DCCB were analytically evaluated using a four-terminal radial HVDC network model. The results show that DC fault interruption current and fault clearing time are achievable by using a mechanical DCCB with the forced current zero formation scheme. Furthermore, interruption performance of the mechanical DCCB composed of HV vacuum interrupter was evaluated. This DC circuit breaker successfully interrupted a current equivalent of up to 16 kA DC in the laboratory. The prototype adopts forced current zero formation scheme and comprises of a highvoltage AC vacuum circuit breaker at transmission voltages connected to an external capacitor equipped with a triggering gap. A series of interruption tests performed on this breaker verified the clearance of short circuit currents as high as 16 kA DC within a few ms after an opening command.

BACKGROUND: The current study aimed to evaluate the efficacy of superselective high‐dose cisplatin infusion with concomitant radiotherapy (RADPLAT) for previously untreated patients with advanced cancer of the nasal cavity and paranasal sinuses. METHODS: Between October 1999 and December 2006, 47 patients were given superselective intra‐arterial infusions of cisplatin (100‐120 mg/m2 per week) with simultaneous intravenous infusions of thiosulfate to neutralize cisplatin toxicity and conventional external‐beam radiotherapy (65‐70 grays). RESULTS: There were 7 patients (14.9%) diagnosed with T3, 22 (46.8%) with T4a, and 18 (38.3%) with T4b disease. During the median follow‐up period of 4.6 years, the 5‐year local progression‐free survival rate was 78.4% for all patients (n = 47), 69.0% for patients with T4b disease (n = 18), and 83.2% for patients with

Purpose: To investigate the correlation between perfusion-related parameters obtained with intravoxel incoherent motion (IVIM) and classical perfusion parameters obtained with dynamic contrast-enhanced (DCE) MRI in patients with head and neck squamous cell carcinoma (HNSCC), and to compare direct and asymptotic fitting, the pixel-by-pixel approach, and a region of interest (ROI)-based approach respectively for IVIM parameter calculation. Materials and Methods:Seventeen patients with HNSCC were included in this retrospective study. All MR scanning was performed using a 3T MR unit. Acquisition of IVIM was performed using single-shot spin-echo echo-planar imaging with three orthogonal gradients with 12 b-values (0, 10, 20, 30, 50, 80, 100, 200, 400, 800, 1000, and 2000). Perfusion-related parameters of perfusion fraction 'f' and the pseudo-diffusion coefficient 'D*' were calculated from IVIM data by using least square fitting with the two fitting methods of direct and asymptotic fitting, respectively. DCE perfusion was performed in a total of 64 dynamic phases with a 3.2-s phase interval.The two-compartment exchange model was used for the quantification of tumor blood volume (TBV) and tumor blood flow (TBF). Each tumor was delineated with a polygonal ROI for the calculation of f, f･D* performed using both the pixel-by-pixel approach and the ROI-based approach. In the pixel-by-pixel approach, after fitting each pixel to obtain f, f･D* maps, the mean value in the delineated ROI on these maps was calculated. In the ROI-based approach, the mean value of signal intensity was calculated within the ROI for each b-value in IVIM images, and then fitting was performed using these values. Correlations between f in a total of four combinations (direct or asymptotic fitting and pixel-by-pixel or ROI-based approach) and TBV were respectively analyzed using Pearson's correlation coefficients. Correlations between f･ D* and TBF were also similarly analyzed. Results:In all combinations of f and TBV, f･D* and TBF, there was a significant correlation. In the comparison of f and TBV, a moderate correlation was observed only between f obtained by direct fitting with the pixel-by-pixel approach, whereas a good correlation was observed in the comparisons using the other three combinations. In the comparison of f･D* and TBF, a good correlation was observed only with f･D* obtained by asymptotic fitting with the ROI-based approach. In contrast, moderate correlations were observed in the comparisons using the other three combinations. Conclusion:IVIM was found to be feasible for the analysis of perfusion-related parameters in patients with HNSCC. Especially, the combination of asymptotic fitting with the ROI-based approach was better correlated with DCE perfusion.

Background:The purpose of this study was to evaluate the efficacy of superselective cisplatin infusion with concomitant radiotherapy (RADPLAT) for previously untreated patients with the squamous cell carcinoma of maxillary sinus (SCC-MS).Methods:Between 1999 and 2010, 54 patients were given superselective intra-arterial infusions of cisplatin (100–120 mg m−2 per week) with simultaneous intra-venous infusions of thiosulfate to neutralise cisplatin toxicity and conventional radiotherapy (65–70 Gy).Results:One patient (1.9%) was diagnosed with T2, 14 (25.9%) with T3, 27 (50%) with T4a, and 12 (22.2%) with T4b disease. Lymph-node involvement was present in 12 patients (22.2%). During the median follow-up period of 6.4 years, the 5-year local progression-free and overall survival rates were 65.8 and 67.9% for all patients, respectively. No patient died as a result of treatment toxicity or experienced a cerebrovascular accident. Osteonecrosis (n=5), brain necrosis (n=1), and ocular/visual problems (n=14) were observed as late adverse reactions.Conclusion:We have shown excellent overall survival and local progression-free rate in SCC-MS patients treated by RADPLAT with acceptable rates of acute and late toxicity. A multi-institutional trial is needed to prove that this strategy is a feasible and effective approach for the treatment of SCC-MS.

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