Management of health and safety in carcinogenesis bioassay programs.

Working with proven or potential chemical carcinogens on a routine basis presents complex safety and health problems. These are compounded when a number of laboratories under separate managements are brought together under a centrally supervised study. This paper presents the types of hazards encountered in such a program and describes the approach used in its overall management. Significant improvements in worker health and safety are being achieved through a centrally-coordinated system of self-assessments, hazard surveys, facility monitoring, and chemical control evaluations.

Evaluation of ECG gating for selective intraarterial carotid DSA.

A study comparing ECG-gated and nongated acquisition for selective carotid digital subtraction arteriography was performed on 116 bifurcations in 63 patients. For ECG acquisition, three exposures (systole, early diastole, and late diastole) were obtained for each cardiac cycle. There was no significant difference in the frequency of plaque misregistration between gated (18%) and nongated (23%) acquisitions. In gated studies, the frequency of plaque misregistration was equivalent in systole, early diastole, and late diastole. Gated and nongated studies provided equivalent image quality for selective carotid digital subtraction angiographic studies.

Evaluation of ECG gating and hybrid subtraction for intraarterial digital subtraction thoracic aortography.

A comparative study was made of ECG-gated and nongated intraarterial digital subtraction angiography of the thoracic aorta by using conventional temporal subtraction and combined temporal/energy (hybrid) subtraction. ECG-gated studies were acquired at three frames per cardiac cycle. In 85% of patients, gated conventional subtraction resulted in studies of superior image quality in comparison with those obtained with hybrid techniques, both gated and nongated. In the 15% in whom hybrid subtraction studies were judged superior, the hybrid images were almost exclusively integrated by video frame averaging and thus were nongated. In a separate subset of patients who had conventional nongated studies, there was no difference in the percentage of diagnostic studies (93%) and nondiagnostic studies (7%) when compared with conventional gated temporal subtraction. Cardiac gating appears to be superior to hybrid subtraction for studies of the thoracic aorta that use intraarterial digital subtraction angiography, but neither technique offered any significant advantage over conventional nongated acquisition.

The role of arteriography in acute penetrating trauma to the extremities.

The role of arteriography was studied in a series of 98 patients presenting with acute penetrating trauma to their extremities. We concluded: (1) Following "proximity only" injury, arteriography is indicated since vessel damage may occur despite a lack of either signs or symptoms; proximity only injuries, however, do not require emergency angiography. (2) Negative arteriography is reliable in excluding arterial injury, and (3) not all angiographic abnormalities require surgery.