Respiratory Gating for Radiotherapy: Main Technical Aspects and Clinical Benefits

Figure 3

Diagram of the respiratory trace visualized by the patient in goggles screen and the therapist with the SDX device during a self-held breath-hold. The patient sees the evolution of his lung volume over time (yellow curve) and its breathing amplitude (green zone) predetermined during the training session. After three cycles of free-breathing, the patient is asked to reach this amplitude and to maintain its breath-hold (yellow plateau of the curve). During this period the CT scan acquisition or irradiation is done. He then resumed his normal breathing.