Figure 2From: Verifying 4D gated radiotherapy using time-integrated electronic portal imaging: a phantom and clinical studyTumor surrogates imaged in patient 1 (left) were the carina bifurcation (A), proximal bronchus bifurcation (B) and the internal target volume (ITV) contour is superimposed. Cranial (C) and caudal clips (D) were surrogates for patient 2.Back to article page