Aluminum, yttrium, copper, and R-filters were evaluated with respect to effective beam energy, entrance radiation exposure to the skin, x-ray tube loading, and the quality of resultant radiographs. Since all filters yielded acceptable radiographs, a figure of merit was developed to determine which filter delivered the lowest entrance radiation exposure for the lowest increase in x-ray tube loading. The figure of merit indicated that the best results were obtained with the 0.1-mm Cu filter with 2 mm Al at 60-105 kVp and with the 0.2-mm Cu filter with 2 mm Al at 105-120 kVp. Cu filters produced radiographs with quality comparable to that of R- or Y filters. Cu filters are inexpensive alternatives to rare-earth filters and yielded a reduction in radiation exposure with less x-ray tube loading.

Remote afterloading high-dose-rate brachytherapy (RAHDRB) was used endobronchially for the management of malignant airway obstruction in 82 patients, 72 of whom had primary disease in the lung. Treatment was palliative (n = 58) or definitive (n = 24). The extent of airway compromise was determined at bronchoscopy and with symptoms of hemoptysis, dyspnea, or cough or with radiographic evidence of atelectasis. RAHDRB doses were 1,000-4,700 cGy in one to five fractions. External beam radiation was used in previously unirradiated patients. A substantial reduction ,N airway disease and an improvement in symptoms were seen in 82% of patients. Obstruction scores showed an overall 74% improvement. Complications occurred in only 10 patients (two of whom died). Median survival was short (palliative group, 5 months; definitive group, 12 months); however, symptoms remained palliated in 62 patients (76%) until death or the last follow-up examination. RAHDRB is effective and can be applied with equal success in all patients with malignant airway obstruction, even those whose disease has recurred after external beam irradiation.

No abstract

No abstract