Mi-Ae Park and colleagues from the Radiology Department of Brigham and Women's Hospital and Harvard Medical School have designed a SPECT collimator pair, to be used on dual head systems, to increase sensitivity, particularly in the center of the brain, while maintaining spatial resolution. They then compared the collimator pairs to conventional systems on the basis of performance in estimating activity concentration of small structures at various locations in the brain.
The collimator pairs evaluated included a cone-beam collimator with short focal length for increased sensitivity, paired with a fan-beam collimator with longer focal length for data sufficiency. The results, presented at the Society of Nuclear Medicine's 50th Annual Meeting, found that the best collimator pair was a cone-beam collimator with a 20 cm focal length and a fan-beam collimator with a 40 cm focal length. Park and colleagues concluded, "combining fan-beam and short-focusing cone-beam collimation should greatly improve dual-head SPECT images, especially when imaging structures located centrally in the brain, such as striata."