Figure 1.

Elekta Response gating control interface: $\mathrm{a}=\text{gating switch box}$; $\mathrm{b}=\text{relay module}$; $\mathrm{c}=\text{LEDs}$; $\mathrm{d}=\text{duplex fiber optic cable}$, which connects the gating switch box and the relay module; $\mathrm{e}=\text{USB}$ cable for gating signal input; $\mathrm{f}=\text{power supply}$; $\mathrm{g}=\text{relay}‐\text{PRF cable}$, which connects directly to the PRF EN chain of the Elekta linac; $\mathrm{h}=\text{duplex fiber optic cable connectors}$.