Figure 1.
(a) Axial placement of the septa (thin vertical lines) in partial collimation modes. The thick vertical lines at either end indicate end-shielding. There are four detector blocks axially, each with six crystals along the axis. The image is not to scale. (b) Individual collimator segments for the 2D and 2.7D collimators. The thicker end shields are evident on top.