Robert C. Murry

The effect of fatigue on resident performance.

Fourteen rested and fatigued residents read a set of 25 test radiographs on two separate occasions approximately one month apart. The radiographs were made with partial chest phantom using pulmonary nodules as test objects. Seven rested and 7 fatigued residents read the radiographs, and a month later the order of fatigue was reversed. Fatigued residents had worked a minimum of 15 consecutive hours before their interpretations. Performance did not deteriorate with fatigue, and the nodule detection rate was almost identical on both occasions.

Grid versus non-grid techniques for the detection of pulmonary nodules in a chest phantom.

A partial chest phantom was constructed to compare two commonly employed radiographic techniques, 70 kVp without a grid and 120 kVp with a grid, for the detection of pulmonary nodules. The phantom consisted of human ribs embedded in paraffin, the lungs of a dog injected with silicone rubber, a tissue equivalent wax heart and beeswax nodules. The nodules ranged in size from 3-7 mm. A series of 120 films was exposed, half with each technique, and the films were interpreted by three senior residents and seven staff radiologists. More nodules of all sizes except 3 mm were detected with the 120 kVp technique. The 3 mm nodules were rarely detected with either technique. The disadvantages of the 120 kVp technique were an approximate 50 percent increase in patient exposures and almost twice as many false-positive nodule detections.

Effect of collimator motion on image quality in nuclear medicine.

To investigate the quality of gamma camera images obtained with moving collimators, a group of collimators was constructed which could be rotated or sinusoidally oscillated in two dimensions. The date indicate a broadening effect on images in the direction of collimator motion. Moving the collimator during imaging will reduce septal aberrations but will not increase resolution.