First Simultaneous Acquisition of a Clinical SPECT-MRI Brain INSERT

The INSERT (INtegrated SPECT/MRI for Enhanced stratification of brain tumours in Radio-chemoTherapy) is currently the only MRI-compatible SPECT stationary system for clinical application, in particular for brain multimodal imaging with an inner bore of 28 cm and a field of view of 20 cm (transaxial) × 10 cm (axial). The intrinsic spatial resolution is 1 mm and the extrinsic one is 10 mm. This modular scanner fits in an unmodified MRI scanner and is a scale-up of a smaller preclinical version, whose mutual compatibility with MRI was extensively characterized. It is composed of 20 detection modules (with 8-mm thick CsI:Tl scintillators of 5 cm 10 cm area read by an array of SiPM) and a massive multi-mini×slit-slat collimator, realized in tungsten. Here we report the first demonstration of successful simultaneous SPECT/MRI acquisition of phantoms (hot rods) using a commercial transceiver coil in a Siemens Biograph mMR scanner.