| 摘要 |
<p>A gamma camera system has an array of photomultiplier tubes for detecting scintillation events, and further has preamplifiers connecting each photomultiplier tube to a weighting resistor matrix for determining the position coordinates of the events. A summing amplifier is provided for summing the signals from all photomultiplier tube preamplifiers to obtain the total energy of each event. In one embodiment, at least two different percentages of the summed signal are developed and used to change the gain of the preamplifiers as a function of total energy when energies exceed specific levels, to obtain more accurate correspondence between the true coordinates of the event and its coordinates in a display.</p> |
