The use of larger scintillation detectors with high-efficiency converging collimators has greatly increased the photon input rate to the crystals of scintillation cameras in many clinical studies. To process these high-count-rate data accurately, modifications have been made by some manufacturers in the electronics of scintillation cameras. Cameras with new electronic design were compared with earlier models with respect to count rate processing capability and the effect of high input rate on spatial resolution, pulse-pair pileup, image size, and instability of the amplification of energy pulses. The improvements with the new electronic design result in shorter imaging times, better preservation of resolution, increased statistical reliability, and reduced distortion of dynamic tracer curves used for quantitative analysis.