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Methane pyrolysis using a molten metal process to produce hydrogen is compared to steam methane reforming (SMR) for the industrial production of hydrogen. Capital and operating cost models for pyrolysis and SMR were used to generate cash-flow and production costs for several different molten pyrolysis systems. The economics were most sensitive to the methane conversion and the value obtained for the solid carbon by-product. The pyrolysis system at 1500 °C is competitive with a carbon tax of $78 t−1; however, if a catalytic process at 1000 °C were developed using a conventional fired heater, it would be competitive with SMR without a carbon dioxide cost penalty. Several pyrolysis alternatives become competitive with increasing carbon dioxide taxes.

Variations in tube output, film processing, and radiologist’s preferences affect the screen–film combination that is appropriate for any particular mammographic facility. A technique to test a variety of screen–film combinations for screening mammography is described. Films are selected for testing because of their sensitometric characteristics. Dose and clinical reliability are established with phantoms before the screen–film combinations are used to image consecutive patients having bilateral examinations. The mammograms selected for evaluation are those with similar optical density ranges, and which also may be compared to available previous mammograms or which have unusual mammographic findings. All radiologists reading mammograms at a facility independently score the selected cases. Scores of ‘‘unacceptable,’’ ‘‘acceptable,’’ or ‘‘outstanding’’ are assigned to four basic imaging characteristics: sharpness, contrast, visibility of skin line, and noise. Interobserver variations by this method require normalization, unlike ROC analysis which is not applicable for this data because of the absence of proved pathologic diagnoses. The testing of 5 films and two screens using 42 patient examinations required 2 h of time from each radiologist. It took 7 h of the physicist’s time to pretest the 5 films, select the 42 acceptable examinations for testing by the radiologists, and summarize the data.

The authors report the accuracy of mammographically guided fine-needle aspiration (FNA) for the diagnosis of nonpalpable breast lesions in a series of 71 patients. Each mammographically guided FNA was immediately followed by hookwire localization and open biopsy. Seven malignancies were identified cytologically, but three cancers were not detected in aspirates judged to be sufficient for diagnosis. In addition, 19 aspirates were reported to be insufficient, and 4 of these were obtained from lesions histologically proven to be adenocarcinoma. Although no false-positive diagnoses were encountered, the technique demonstrated a sensitivity of 78% and a diagnostic accuracy of 94% for adequate specimens. In this study, mammographically guided FNA was insufficiently sensitive to replace open biopsy for the diagnosis of nonpalpable breast lesions.