FIGURE 1.

The configuration of the developed couch speed verification system (a). Pulse signals were acquired by connecting a wire attached to the external side of the Radixact couch to the rotary unit of the encoder. The pulse signals were output as quadruplicated by a data output counter, and the couch speed (cm/sec) and relative position (cm) were monitored via periodic calculations. The pulse signals were also acquired using data collection software to enable numerical analyses. A laser distance sensor was fixed at the bore side end of the couch to detect the starting position of the couch movement (b). DL, data logger.