BrainPet 7T
Positron emission tomography of the brain is used to measure brain metabolism and the distribution of exogenous radioactively labelled chemicals in the brain. A PET measures the emissions of radioactively labelled, metabolically active chemicals that are injected into the bloodstream. The emission data from the brain PET is analysed using computers to create multidimensional images of the distribution of the chemicals in the brain. The new PET application will significantly increase the evaluation options compared to conventional PET scanners.
ZEA-1 designed the gantry, including the covers for the PET detectors and the required electronics. The gantry carries the detectors, the electronics and the cooling structures, among other things. It is made of glass fibre-reinforced plastic, which enables a non-magnetic and at the same time light and rigid structure.
A transport and assembly trolley was developed for handling the PET scanner, which enables the gantry to be rotated 360° for the assembly of the detectors and infrastructure. A related task of the transport and assembly trolley is the insertion and removal of the scanner in the MRI, as well as interim storage after the measurements.
The gantry is complemented by the corresponding cooling circuit for the scanner. It consists of a manifold for the supply and return lines. The supply and return lines are divided into 8 lines where the flow rate to the individual detector electronics units can be adjusted. A further contribution was the bonding of the Lightguide scintillators with the photomultipliers to form finished detectors. A total of 120 detectors were required. Various devices were developed in order to realise a uniform layer thickness of the adhesive.
The adhesive between the scintillators and the photomultiplier has a layer thickness of 50 µm; it had to set without bubbles in order to achieve a high evaluation quality. The bonding wires of the photomultiplier had to be encapsulated on two sides with a low-viscosity adhesive to prevent mechanical damage.
Various components were produced using a 3D printer in connection with the BrainPet 7T project. These included a drip tray to collect and drain any leaks. The geometry was printed from PC-ISO to match the gantry. PC-ISO (FDM thermoplastic) is a biocompatible and sterilisable polycarbonate (PC) for 3D printing.
One other component designed in the ZAE-1 is the headrest. It holds the patient's head in the BrainPet during the measurement. The headrest was printed in the INM-4.
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