Results from prototype II of the BNL simultaneous PET-MRI dedicated breast scanner

At Brookhaven National Laboratory, we are developing a simultaneous PET-MRI breast imaging system. A prototype II version of the PET system has been constructed. This device consists of 24 detector blocks where each block consists of a 4 × 8 array of 2.2 × 2.2 × 15 mm
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LYSO crystal directly coupled to a 4 × 8 non-magnetic APD array. The scanner has an inner diameter of 100 mm and an axial extent of 18 mm. Resolution measurements were carried out for the prototype system to evaluate the depth of interaction effects. Average resolution less than 2 mm FWHM was maintained throughout the field of view. The prototype PET system was operated unshielded inside the RF coil of the Aurora 1.5 T dedicated breast MRI machine. Artifact free MRI images with good SNR were obtained.