Fig. 2.

Irradiation with deep inspiration and respiratory arrest. The patient wears a belt, by which the breathing is detected. In the control room, the technician can follow the respiratory excursions on the monitor. Irradiation is performed in a defined respiratory position (after command: ‘Please inhale deeply and hold the breath’) and may be interrupted. Depending on the duration of irradiation (usually 20–30 s per irradiation field) 1 or 2 respiratory cycles per treatment field are required.