A tape-recording system using a variation of pulse-width modulation records up to 28,000 Hz from an Anger camera without spatial or tern

pulse-width modulation records up to 28,000 Hz from an Anger camera without spatial or tern poral distortion and with less than 1 % data loss. Recording and playback may be made at any of five tape speeds: 3%, 71,4, 15, 30, 60 ips, each accommodating a different maximal count ing rate. Since only two of four recording tracks are used, the others are available for other in put. The replayed data appear in a format iden tical to the gamma camera signal; hence, any data manipulation performable on the original signal can be carried out on the replay. The system has advantages over other gamma cam era recording systems : matrix artifact is elimi nated; replay time may be accelerated or decel erated depending upon study objectives; when data are digitized for computer manipulation, data losses caused by deadtime are limited to those intrinsic to the gamma camera itself.