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Figure 6. A typical field arrangement for a spinal field
45 cm. The central axis of the open fields is indicated by the solid green line. The extent of the open radiation fields is indicated by the dashed green lines, the two junctions in the upper cervicothoracic region. The extent of the two additional segments, one in the thoracolumbar region and the other in the lumbosacral region is indicated by the dotted yellow lines. The central axis of the asymmetric beamlets is indicated by the solid blue line. The limits of the three pairs of beamlets in the cervicothoracic region are indicated by the pairs of dotted blue lines.
