A device that generates low-energy x rays at the tip of a needle-like probe was developed for stereotactic interstitial radiosurgery. Electrons from a small thermionic gun are accelerated to a final energy of up to 40 keV and directed along a 3 mm outside diameter drift tube to a thin Au target, where the beam size is approximately 0.3 mm. All high-voltage electronics are in the probe housing, connected by low-voltage cable to a battery-operated control box. X-ray output, which is nearly isotropic, consists of a bremsstrahlung spectrum and several lines between 7 and 14 keV, with characteristic radiation contributing 15% of the total energy output. To date, 14 patients with metastatic brain tumors have been treated with this device.
BackgroundBarcode-based technology coupled with the electronic medication administration record (e-MAR) reduces medication errors and potential adverse drug events (ADEs). However, many current barcode-enabled medication administration (BCMA) systems are difficult to maneuver and often require multiple barcode scans. We developed a prototype, next generation near field communication-enabled medication administration (NFCMA) system using a tablet.ObjectiveWe compared the efficiency and usability of the prototype NFCMA system with the traditional BCMA system.MethodsWe used a mixed-methods design using a randomized observational cross-over study, a survey, and one-on-one interviews to compare the prototype NFCMA system with a traditional BCMA system. The study took place at an academic medical simulation center. Twenty nurses with BCMA experience participated in two simulated patient medication administration scenarios: one using the BCMA system, and the other using the prototype NFCMA system. We collected overall scenario completion time and number of medication scanning attempts per scenario, and compared those using paired t tests. We also collected participant feedback on the prototype NFCMA system using the modified International Business Machines (IBM) Post-Study System Usability Questionnaire (PSSUQ) and a semistructured interview. We performed descriptive statistics on participant characteristics and responses to the IBM PSSUQ. Interview data was analyzed using content analysis with a qualitative description approach to review and categorize feedback from participants.ResultsMean total time to complete the scenarios using the NFCMA and the BCMA systems was 202 seconds and 182 seconds, respectively (P=.09). Mean scan attempts with the NFCMA was 7.6 attempts compared with 6.5 attempts with the BCMA system (P=.12). In the usability survey, 95% (19/20) of participants agreed that the prototype NFCMA system was easy to use and easy to learn, with a pleasant interface. Participants expressed interest in using the NFCMA tablet in the hospital; suggestions focused on implementation issues, such as storage of the mobile devices and infection control methods.ConclusionsThe NFCMA system had similar efficiency to the BCMA system in a simulated scenario. The prototype NFCMA system was well received by nurses and offers promise to improve nurse medication administration efficiency.
Miniature x-ray sources present unique challenges due to the cost, power and space constraints placed upon them. One of the key functional differences from larger traditional x-ray tubes is that the x-ray spot is comprised of the entirety of the electrons produced by the filament without the benefit of active focusing elements in most cases. The result is an x-ray spot that is not well described by a traditional Full Width Half Maximum (FWHM) type of measurement due to the irregular nature of the spots. This paper presents an alternate method called an intensity integral curve that can be used in conjunction with a Gaussian FWHM measurement. The intensity integral curve gives important additional spatial information about the x-ray spot and more predictive power in how the x-ray spot on the tube may perform in a given application. The experimental setup, curve generation and curve interpretation are discussed for a number of currently available and prototype miniature x-ray sources. 1.
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