RESUMEN

On 11 December 1991, a radiation overexposure occurred at an industrial radiation facility in Maryland. The radiation source was a 3-MV potential drop accelerator designed to produce high electron beam currents for materials-processing applications. This accelerator is capable of producing a 25 milliampere swept electron beam that is scanned over a width of 112.5 cm and which emerges from the accelerator vacuum system through a titanium double window assembly. During maintenance on the lower window pressure plate, an operator placed his hands, head, and feet in the beam. This was done with the filament voltage of the electron source turned "off," but with the full accelerating potential on the high voltage terminal. The operator's body, especially his extremities and head, were exposed to electron dark current. In an attempt to reconstruct the accident, radiochromic film and alanine measurements were made with the accelerator operated at two beam currents. Measured dose rates ranged from approximately 40 cGy s-1 inside the victim's shoe to 1,300 cGy s-1 at the hand position. Approximately 3 mo after the accident, it was necessary to amputate the four digits of the victim's right hand and most of the four digits of his left hand. Electron paramagnetic resonance spectrometry, which measures the concentration of radiation-induced paramagnetic centers in calcified tissues, was used to estimate the dose to the victim's extremities. A mean dose estimate of 55.0 +/- 3.5 Gy (95% confidence level) averaged over the mass of the bone was obtained for the victim's left middle finger (middle phalanx).

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RESUMEN

In 1986, a practice management training program was developed for pediatric house staff. In conjunction with this program, pediatric residents for the following 2 years completed questionnaires regarding their career goals, interests, and perceived competence in practice management. Postgraduate level-3 residents who completed the program felt more competent than postgraduate level-1 residents in all areas of practice management and were more likely to take an active role in managing their practice. There was a significant difference between postgraduate level-1 and level-3 residents who completed the program in several areas: feelings of overall competence in office management, choosing a practice location, office staff, appointment system, billing system, office computer, fee schedules, telephone management, and setting up an office laboratory. Exposure to a practice management program during residency training may better prepare future pediatricians for a successful practice.

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A short-exposure, high-energy holography system has been constructed which yields high quality holograms of scenes several cubic meters in volume. The system is constructed around a single mode Q-switched ruby oscillator and a 20-dB gain single-pass ruby amplifier. The output is fully coherent at peak output of 10 J. Front lit holograms of transient events and of live subjects have been made with this system.