RESUMEN
Laser-based scanners provide a sensitive means for measuring optical density (OD) of Gafchromic films. Such instruments were reviewed in a recent AAPM report (task group 55) which provided recommendations and information on OD measurements (effect of wavelength, temperature, etc.). The present article reports that variable rate scanners and spot densitometers using laser diodes (671 nm) and HeNe lasers (633 nm) can cause polymerization of Gafchromic film. The light induced polymerization depends on light power, wavelength, beam spot size, dwell time, and prior radiation dose of the film. Measurements were made with a custom built scanner that provided accurate control of light power, light polarization, dwell time, and film position in relation to the beam focus. The results demonstrate that lasers operating with powers of 0.1, 0.5, 1.0, and 1.5 mW produce a nonlinear increase in OD of Gafchromic film. The measured change in OD after 1 min of exposure ranges from 0.150 to 0.244 for a laser diode operating at 0.5 and 1.5 mW, respectively. Tables are included that tabulate the increase in OD for laser power, dwell time, and prior dose. Laser light induced polymerization can have a significant impact on dosimetry measurements acquired using these laser-based systems.
Asunto(s)
Dosimetría por Película/instrumentación , Fenómenos Biofísicos , Biofisica , Dosimetría por Película/estadística & datos numéricos , Humanos , Rayos Láser , Óptica y Fotónica/instrumentaciónRESUMEN
In this article we try to determine how frequently emergency physicians (EPs) suspected the diagnosis in acute aortic dissection (AD). In this retrospective descriptive study, we identified all patients with the final diagnosis of AD initially evaluated in 1 of 3 emergency departments (EDs) over a 5-year period. Patients were included if AD was not suspected before ED evaluation. Patients undergoing thoracic aorta imaging as the initial ED study were defined as suspected AD. Forty-three patients totaling 44 presentations were identified. EPs suspected AD in 19 of 44 presentations. EPs suspected AD in 12 of 14 (86%) cases of chest and back pain and in 5 of 11 (45%) of chest pain. Thirteen of 39 (33%) painful presentations involved abdominal pain; EPs suspected AD in 1 of 13 (8%). EPs suspected the diagnosis in 43% of acute AD; location of pain was most predictive of a suspected diagnosis.
Asunto(s)
Aneurisma de la Aorta Torácica/diagnóstico , Disección Aórtica/diagnóstico , Tratamiento de Urgencia/métodos , Enfermedad Aguda , Adulto , Distribución por Edad , Anciano , Anciano de 80 o más Años , Disección Aórtica/clasificación , Disección Aórtica/complicaciones , Aneurisma de la Aorta Torácica/clasificación , Aneurisma de la Aorta Torácica/complicaciones , Dolor de Espalda/etiología , Causalidad , Dolor en el Pecho/etiología , Servicio de Urgencia en Hospital , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Estudios Retrospectivos , Análisis de SupervivenciaAsunto(s)
Certificado de Necesidades/economía , Planificación Hospitalaria/economía , Regionalización/economía , Gastos de Capital/legislación & jurisprudencia , Certificado de Necesidades/legislación & jurisprudencia , Análisis Costo-Beneficio , Costos y Análisis de Costo , Honorarios y Precios , Agencias Gubernamentales , Massachusetts , Factores de Tiempo , Estados UnidosRESUMEN
Many general psychiatrists, on the basis of long clinical experience, use electroconvulsive therapy (ECT) as an important treatment modality in acute schizophrenic disorders. They believe its use, along with phenothiazine drugs and supportive psychotherapy, produces a superior remission in a shorter time in many instances. The charts of one hundred consecutive first hospital admission schizophrenics at Glenside Hospital were reviewed regarding treatment modalty, length of stay, and outcome, as part of a utilization review study. The average hospital stay was thirty-one days. Eighty-eight per cent were discharged home improved. Fifty-six per cent received ECT.