Søren Baarsgaard Hansen, March 2017

The HRRT (High Resolution Research Tomograph) scanner was delivered from Siemens Healthcare and installed in 2005. The system has been developed by Siemens (former CTI) as a dedicated brain scanner for research, and it has been delivered only to selected centers worldwide. Most remarkable the specifications includes an outstanding spatial resolution around 2 mm compared to typically 4 mm for modern clinical whole-body scanners. This very high spatial sampling has been achieved by incorporating both quadrant sharing and depth-of-interaction detector technology. Data are acquired in list-mode for maximum flexibility regarding post scanning data processing of dynamic studies. Attenuation correction is based on transmission scans using a 137Cs point source.
The software is partly developed in collaboration between the HRRT centers, and includes many processing options as well as reconstruction algorithms like FBP, OSEM, and OSEM with point spread modelling (PSF). Data processing also includes image based motion correction, which in particular is to the benefit for longer dynamic studies. Apart from human heads, the HRRT is suitable for scanning medium-sized animals like rats, rabbits and pigs.