Fan-Shaped Complete Block on Helical Tomotherapy for Esophageal Cancer: A Phantom Study

Figure 1

The fan-shaped block of FSCB 100° (pink area) was defined by the intersection of beam angle of 40° and 140°. The PTV was shown in red and the blue line defined the block auxiliary structure which was sufficient to cover 1.5 cm expanded from the PTV (yellow circle).