Frequency jitter and spectral width of an injection-seeded Q-switched Nd:YAG laser for a Doppler wind lidar

The design of a 50 Hz single longitudinal mode, diode-pumped and frequency-tripled Nd:YAG master oscillator power amplifier is described, and the first measurements of output parameters are presented. The laser oscillator is injection-seeded by a tuneable monolithic Nd:YAG ring laser and frequency stabilized by minimising the Q-switch build-up time. The laser system will be an integral part of an airborne instrument demonstrator for a first satellite based Doppler wind lidar to measure vertical profiles of one component of the atmospheric wind vector. This paper focuses on the investigation of the frequency jitter and the linewidth of the laser, which are measured on a pulse-to-pulse basis. For this purpose a compact, high accuracy beat frequency monitoring system has been developed at DLR. By operating the amplifier stage at half the repetition rate (50 Hz) of the oscillator, we could reduce the frequency stability from 10 MHz (rms) to 1.3 MHz (rms) (over a 14 s period). We have determined a mean linewidth of 15 MHz (FWHM) at 1064 nm. These measured laser parameters enable wind velocity measurements in the atmosphere (0–15 km) at an accuracy of 1 to 2 m/s

Applicability of DICOM structured reporting for the standardized exchange of implantation plans

PURPOSE: Today's operating room is equipped with different devices supporting the surgeon. Due to the lack of common interfaces between devices, an integrated support of the surgical workflow is missing. In the field of implantation, a smooth exchange of preoperatively planned data between devices is of great interest. Additionally, the availability of standardized preoperative data would facilitate the documentation, especially with regard to Electronic Health Records. METHODS: To analyze whether DICOM Structured Reporting can be the basis for a standardized digital human- and machine-readable implantation plan, we derived all requirements for such a document. Therefore, we examined the conventional implantation plan and future applications of the digital plan. RESULTS: In this paper, we propose to use the mechanisms introduced by DICOM Structured Reporting as storage and communication infrastructure for implantation plans in the surgical domain. DICOM Structured Reporting complies with all requirements of our analysis. Additionally, we introduce a first draft of a standardized implantation plan structure. CONCLUSIONS: A standardized digital implantation plan based on the DICOM Structured Report has the potential to overcome current integration problems in the OR and to facilitate new applications

DICOM for Implantations—Overview and Application

Surgeons have to deal with many devices from different vendors within the operating room during surgery. Independent communication standards are necessary for the system integration of these devices. For implantations, three new extensions of the Digital Imaging and Communications in Medicine (DICOM) standard make use of a common communication standard that may optimise one of the surgeon's presently very time-consuming daily tasks. The paper provides a brief description of these DICOM Supplements and gives recommendations to their application in practice based on workflows that are proposed to be covered by the new standard extension. Two of the workflows are described in detail and separated into phases that are supported by the new data structures. Examples for the application of the standard within these phases give an impression of the potential usage. Even if the presented workflows are from different domains, we identified a generic core that may benefit from the surgical DICOM Supplements. In some steps of the workflows, the surgical DICOM Supplements are able to replace or optimise conventional methods. Standardisation can only be a means for integration and interoperability. Thus, it can be used as the basis for new applications and system architectures. The influence on current applications and communication processes is limited. Additionally, the supplements provide the basis for further applications, such as the support of surgical navigation systems. Given the support of all involved stakeholders, it is possible to provide a benefit for surgeons and patients