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When an acute internal esposure to plutonium occurs, a number of problems arise for consideration by the treating physician and the attending physicist.-4 recent plutonium wound incident a t Hanford involving the laceration of an employee's arm by plutonium fragments, has again emphasized these problems and the need for great care in wound and patient management, both from a medical and physical standpoint. This paper describes the methods of wound management including surgical removal of the plutonium, use of chelating agents, the methods of evaluating the residual deposition of plutonium, and hopefully indicates areas of needed research.

ENERGY-sensitivity studies of y-ray instruments have indicated strong variations in sensitivity in the energy range below 200 keV (Da51; He52). These studies have been made using heavily filtered X-rays to provide approximately monoenergetic photons. Despite the heavy filtration, there remains a considerable spread in energy of these rays; consequently, their use in an energy range in which the detector sensitivity varies rapidly with energy can be misleading. The "effective energy" of such filtered beams is determined by absorption measurements. In this way, an average is obtained that may represent a different weighting of the energy spectrum than that made by the instrument. We have avoided these difficulties with nearly monoenergetic X-rays of less than 200 keV derived from K-fluorescence.Nearly monoenergetic sources for microradiography of histologic sections (Ro52) and for metallurgical microradiography (Sp32) have already been developed, using the Kfluorescence X-rays produced by irradiating selected secondary targets with ordinary Xrays. These devices are not suitable for instrument calibration because of the small beam size available. It was possible to increase the size of an apparatus of this sort so that a beam uniform in intensity to within a few percent over a 6-in.-diameter circle could be obtained with dose rates adequate for instrument calibration and similar studies.A 220-kvp industrial X-ray machine was used as the source of primary radiation. The minimum voltage to which this machine could be adjusted was 60 kvp. This did not permit selecting a voltage that minimized scattered radiation for characteristic X-rays whose energies were below 60 keV. A lower-voltage machine, particularly one with a beryllium window for greater intensity, would be better. However, it was possible to achieve very satisfactory results with the machine described.The source is shown in the illustration.FIG. 2. X-ray source is constructed of standard 6-in.steel pipe convered with :-in. lead sheet. Standardbrass-tubing sections slide into pipe to support collimators and filters. Second collimator captures photons scattered by first one; third collimator minimizes scattering from 30-cm beam trap into fluorescent beam emerging from side portal. 1075

Therapeutic or industrial X-ray generators can be simply and effectively adapted to the production of K-fluorescence radiation by impinging the primary beam onto an appropriate secondary target. The technique of producing a secondary beam of large diameter with virtually any energy below 100 keV is described. Typical spectra show the beam to be composed almost exclusively of K characteristic radiation, with less than 2% of the total flux attributable to scattering or L-fluorescence if appropriate filtration is used. The essentially monoenergetic beams are extremely valuable for energy depcndence studies of dosimeters and detectors of all types, providing a more intensive study of the response in the 8-100 keVEIl region than is possible with conventional X-ray sources. By use of a radiator with Z near 40, the photon spectrum from 23ePu can be simulated without the necessity of using highly radiotoxic materials. Similar mock spectra can be achieved for 241Am and 243Am. The potential application of this device to radiological standardization is also discussed.

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