Dynamic scintigraphy with high temporal resolution. Phase dynamic studies of rapid periodical processes.

The theory and general method of construction of the phase dynamic studies of rapid periodical processes with high temporal resolution is described briefly. Moreover, problems are discussed that are associated with the introduction of external pulses into dynamic studies in LIST-mode, the spatial and temporal reconstruction from LIST-mode, the computer's construction of phase dynamic studies, the selection of correct cycles, the creation of phase histograms and processing of the phase studies. The method is illustrated by a general program LIST leads to PHASE DYNAM. STUDY created for Clincom apparatus. In addition to the general method, there is mentioned here the modification of the simplified procedure--a well-known EKG-gated method. Some aspects of the method are documented by the results of phantom measurement and clinical examinations.

Dead-time correction in dynamic radionuclide studies by computer.

Several methods for the measurement of dead time and for evaluation of the dependencies required to correct dynamic studies for dead-time losses are described. Two program variants were written to produce time-activity curves in the selected areas of interest of the dynamic studies with computer's correction of dead-time losses; these variants are part of the system of programs for complex processing of scintigraphic studies set up for a Clincom instrument. The first variant performs correction on the basis of the registered count rate in the whole image, while the second variant makes us of the additional reference source positioned on the periphery of the camera visual field.