Basic problems in radionuclide digital imaging

We have examined basic problems of radionuclide digital imaging for an archiving and communication system using receiver operating characteristic analysis and power spectrum. By ROC analysis on the 512 and 256 matrix, results were affected by the signal frequency, but not affected by the noise level. For good image quality, radionuclide images with a Nyquist frequency of x4 of signal frequency appeared to be needed. In power spectrum, the signal frequency was by various factors. The maximum signal frequency in clinical images were about 1.5 cycles/cm. Gamma camera system noise was detected in the low noise images. Suitable matrix size was a 5122 matrix for high quality static images, a 2562 matrix in general static image, a 2048 x 512 matrix or a 1024 x 256 matrix for whole body image. Data volume per month was estimated to be about 400 Mbyte in a hospital with 1000 beds, and 100 Mbyte per hospital on the average in Japan. Whole body images have more than half of the total data volume. (author)