RESUMEN
Energy dispersive X-ray diffraction is proposed as a suitable non-destructive method to rapidly identify illicit drugs in parcels. A preliminary data set of 7 illicit drug samples and a possible cutting agent has been collected with a range of count times using a tungsten target X-ray source, a high resolution HpGe detector and a variable geometry diffraction cell. These results have been used to calibrate and train multivariate analysis software to predict the drug content in previously unseen spectra.
Asunto(s)
Drogas Ilícitas/análisis , Radiometría/métodos , Medidas de Seguridad , Detección de Abuso de Sustancias/métodos , Difracción de Rayos X/métodos , Estudios de Factibilidad , Servicios Postales , Dosis de Radiación , Dispersión de Radiación , Sensibilidad y EspecificidadRESUMEN
BACKGROUND AND PURPOSE: Recently, a new-concept lumen-less Teflon-coated double-J wire stent (Zebra stent) has been introduced to facilitate residual stone clearance, in particular after SWL. Its metal core expresses highly mismatched acoustic impedance. It was the aim of this study to exclude damage to the stent through shockwaves. Also, its Teflon coating should to some degree prevent encrustation, and stents removed from stone formers were examined for encrustation. MATERIALS AND METHODS: Series of 2000 shockwaves of an average and a maximum energy were applied to defined areas of Zebra stents in a waterbath on a Siemens Multiline Lithotriptor. Stents were then examined for core and sheath damage by digital photography, scanning electron microscopy, and microradiography. In addition, two Zebra stents and one conventional double-J stent from two stone formers were assessed in the same way for damage and encrustation. RESULTS: There was no damage whatsoever to either of the stents. Whereas there was considerable encrustation on the conventional double-J stent, there was none on the Zebra stents after 4 and 5 weeks in situ. CONCLUSIONS: Zebra stents resist shockwaves to a maximum number and energy sufficiently to be applied safely under SWL. Whether they resist encrustation to a higher degree in the short term than conventional stents remains to be established.