RESUMEN
The effects of the mammography film processing replenishment rate on contrast and speed are studied sensitometrically. Two experiments studied decreasing replenishment rates in the Kodak RP developer and quantified changes in the developer by measuring bromide ion concentrations. First, values of NaBr concentration from 1.7 to 8.4 g/L, achieved by reducing the replenishment rate, were tested with sensitometry strips. Second, the developer replenishment rate of a high volume dedicated mammography processor was reduced by one-third, to 20 cm3/1560 cm2, so that the NaBr concentration rose from 2.0 to 12.36. Sensitometric results for four film types and patient films were tested for changes from standard values as NaBr concentration was restored to 3.31 g/L. Fifty-five clinical images obtained at 7.3-9.3 NaBr g/L were compared to their matching previous films, with NaBr levels of 2-3 g/L, for contrast and visibility of the skin line. For the range of the NaBr ion from 1.7 to 7 g/L, no significant sensitometric differences were found. Above 7 g/L, different film types had different sensitometric results. From 7.3 to 9.3 NaBr g/L, 47.5% of the clinical films reviewed by four radiologists had less contrast compared to previous films. Dedicated mammography processors with high film volume (i.e., those that do not have excessive oxidation or foreign dye problems) can operate at lower replenishment rates than are currently employed. All common mammography film types are stable at these lower replenishment rates up to 7.0 NaBr g/L.
Asunto(s)
Mamografía/normas , Fenómenos Biofísicos , Biofisica , Bromuros , Femenino , Humanos , Mamografía/métodos , Control de Calidad , Compuestos de Sodio , Tecnología Radiológica , Película para Rayos XRESUMEN
Underprocessing of mammographic film can result in reduced contrast and visibility of breast structures and an unnecessary increase in radiation dose to the patient. Underprocessing can be caused by physical factors (low developer temperature, inadequate development time, insufficient developer agitation) or chemical factors (developer not optimized for film type; overdiluted, underreplenished, contaminated, or frequently changed developer). Conventional quality control programs are designed to produce consistent processing but do not address the issue of optimum processing. Optimum processing is defined as the level of processing that produces the film performance characteristics (contrast and sensitivity) specified by the film manufacturer. Optimum processing of mammographic film can be achieved by following a two-step protocol. The first step is to set up the processing conditions according to recommendations from the film and developer chemistry manufacturers. The second step is to verify the processing results by comparing them with sensitometric data provided by the film manufacturer.
Asunto(s)
Mamografía/métodos , Película para Rayos X , Pantallas Intensificadoras de Rayos X , Femenino , Humanos , Mamografía/instrumentación , Mamografía/normas , Fantasmas de Imagen , Control de CalidadRESUMEN
Muscular atrophy and decreased functional abilities are recognized as late complications of poliomyelitis. This study sought to more clearly define late-onset, postpolio muscular weakness--age of onset, symptoms, and severity--and to determine whether people might benefit from environmental modification, respiratory aids, and orthoses. A total of 183 postpolio patients were examined by a physician and completed a questionnaire on their ambulatory status and related musculoskeletal and respiratory symptoms. Of those participating in the study, 154 claimed to be experiencing late deterioration in strength. The syndrome included decreased endurance, more limited ambulation, and increased weakness in the previously affected limb/s. For those describing late-onset weakness, average ages were determined for the onset of polio (8.3 years), the onset of postpolio muscular weakness (42.3 years), and the latent period of stable functioning (34.8 years). Patients claimed to have experienced a new, lower level of strength for an average of 4.7 years. All 33 patients who had undergone muscle transfer surgery were experiencing late-onset weakness in that extremity. Fasciculations (51%) and long-bone fractures secondary to falls (21%) were common sleep disturbances occurred frequently (31%) even in those without prior bulbar involvement. Upper motor neuron signs were present in only one case. Bracing was rare (16%) and the braces used were usually old. The subjects did not report a steadily or rapidly progressive decline, but rather described a steplike decrement with long plateaus. The population described losses in strength that had significant bearing on functional status and general health.(ABSTRACT TRUNCATED AT 250 WORDS)