Slab-Sandwich-Slab Production Methodology
The Slab-Sandwich-Slice (SSS) methodology for block production was developed by our group to produce nearly 40,000 detector elements required for the HOTPET human camera. This method lowers the production cost, increases yield and increases detection efficiency. We start the construction with crystal “slabs” that are many crystal needles wide and one crystal thick. The slabs with reflector pattern placed precisely over them are glued into a crystal “sandwich”. All the “sandwiches” are cross-cut to form the "slices."; each slice is basically a stack of individual crystal. Another set of reflector patterns are placed over the slices and them glued together to form the final detector block.
The SSS production technology can also be applied not only to the PQS position-sensitive crystal arrays but also to the conventional PET blocks. The technology has the potential to lower the cost of all PET, especially ultrahigh-resolution systems. This block production technique leaves only a very small gap between crystals, providing very good detector packing fraction. Increasing the detector-packing density could provide higher coincidence-detection sensitivity.
Slab-Sandwich-Slab Production Methodology
Block Comparison
A comparison of two 7 × 7 BGO crystal arrays produced by two different techniques: A MDAPET block (left) made with the old technique and a HOTPET block (right) made with the SSS production method. Note the much higher packing fraction in the SSS-PQS-detector block.