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Background Larger invasive thymomas are generally resected via an open approach with thoracotomy or sternotomy. Following accumulation of experience and modifications to the technique, certain invasive tumors can be safely resected by video-assisted thoracic surgery (VATS) without resorting to sternotomy. Patients and Methods Thirteen consecutive patients with large invasive thymomas, who underwent bilateral VATS thymectomy, were analyzed retrospectively. Results All patients underwent radical en bloc resection of the tumor and the involved structures, without breaching the tumor capsule or tumor seeding. In one patient, difficulties in removal of the tumors from the left brachiocephalic vein necessitated conversion to an open approach with minithoracotomy. No procedure-related hemorrhage occurred. The average operation time, including the case requiring conversion, was 132 minutes. The mean postoperative hospital stay was 4.7 days. There were no perioperative deaths. All patients completed follow up, with a mean duration of 17.4 months. Follow-up chest computed tomography showed no cases of recurrence. Conclusion With proper patient selection, preoperative planning, and a standardized approach to the operative method, we believe that bilateral VATS thymectomy can be a safe and effective procedure, and may provide an attractive alternative approach to median sternotomy.

This paper presents a semiconductor laser beam shaping system, that can collimate the irradiance profile effectively and package the laser diode(LD) at the same time. Due to the semiconductor LD is a kind of line source, a particular ellipsoidal lens is designed after both the fast-axis and the slow-axis of the laser beam analyzed. Geometrical optics analysis based on the ray tracing method is done and the formulas to calculate the shape of the lens are given. Both the theoretical and experimental result show that the laser beam system works effectively; the divergence angle is reduced to less than 0.5 degree in the fast-axial direction and 1.8 degree in the slow-axial direction. In addition, it is the same process that makes the laser beam shaper and packages the LD by using epoxy resin, which simplifies the manufacturing process and reduces the LD volume greatly. Because of the advantages of small volume, low-cost, high rigidity and easy fabrication, the shaper is of great value in the field of semiconductor LD applications.

The linewidth broadening of Distributed Feedback (DFB) semiconductor lasers under direct modulation become more and more serious with the increase of modulating data rate. So it is important to investigate externally modulated transmitter module whose dynamic linewidth is the same as its static linewidth. The integrated module including DFB-LD and LN modulator reported here has a 3 dB-bandwidth of 3.8 GHz, 4 V drive voltage, and operating wavelength at 1548 nm, its linewidth is about 100 MHz measured by Gated Delay Self Homodyne and output power is 200 (mu) W. It has been used in optical transmission system and shows good characteristics.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.