[Basic study of continuous repetitive data acquisition using a phantom].

We evaluated the appropriate rotation rate in the continuous reverse collection mode of single photon emission computed tomography (SPECT), in phantoms and in volunteers. Since a SPECT examination generally takes 15 minutes, the rotation rate was changed from 1, to 3, 6, 9 and 12/15 minutes. A lower rotation rate resulted in clearer visualization of the lattice and less variance of data in each collection direction in a columnar phantom, and higher image homogeneity and clearer visualization of the defective area in a myocardial phantom. There was a correlation represented by regression equation y = 0.0243x2 - 0.7843x + 98.136 r2 = 0.9802 between the rotation rate and variance of data in each collection direction. There was also a correlation represented by the regression equation y = -0.0034x2 + 0.0157 + 1.2394 r2 = 0.9943 between the rotation rate and the total count corrected with that obtained in the step mode (conventional collection). Better 99mTc-1,2-bis[bis(2-ethoxyethyl) phosphino]ethane (Tetrofosmin) myocardial scintigraphy images were obtained at a lower rotation rate in a normal volunteer. In conclusion, a rotation rate of 3-6/15 minutes may be appropriate in continuous reverse collection.