Biomedical subjects
Publications and source records attributed to L R Carroll.
The sensitivity, resolution, linearity, and count rate capability for the PC 4600 positron emission tomograph (PET), a neurological PET with five rings of 96 bismuth germanate crystals, are reported along with details of the design of this system. Phantom studies and preliminary human images demonstrate the clinical potential of this new instrument.
The nitroglycerin (NTG) exercise test can help in detecting ischemia in the presence of right bundle branch block (RBBB), left bundle branch block (LBBB), or digitalis-induced exercise ST changes and in excluding ischemia when a falsely positive test is suspected. This treadmill test has 3-min stages at 10% grade starting at 1.5 mph and progressing in 0.5 mph increments until ST depression is observed. NTG is then given as exercise continues at the ischemia-provoking work load for up to 10 min. Among 3 patients with RBBB, 5 with LBBB, 1 on digitalis and 2 with presumed falsely positive tests, those whose ST depression lessened after NTG had ischemic thallium exercise scans; those with no change in ST depression after NTG had normal thallium images. Additional studies are needed to verify the consistency of these findings among a larger group of patients.