Validation and evaluation of a GATE model for MAMMI PET scanner

MAMMI is a dedicated PET based on high resolution detectors placed close to the breast. In this study, we presented a GATE model for the simulation of MAMMI scanner and model its performance of the MAMMI based on an adaptation of the NU 4-2008 NEMA standard.  A detailed of geometry MAMMI system that uses scintillation crystals coupled to position sensitive photomultipliers. The detector ring consists of 12 LYSO detector modules with a scanner aperture of 186 mm. We validated the model against experimental measurement, including spatial resolution, sensitivity, counting rates, noise equivalent count rate (NECR) and scattering pattern. Overall results showed reasonable agreement between simulation and experimental data. For a breast phantom with a capillary source, the SF reaches 50.9 and NECR is 45 kcps with an activity of 11 MBq, 18F in quad rings. The spatial resolution at the axial FOV of quad rings (2.1 mm axial, 1.8 mm radial, and 1.7 tangential) is slightly better than that measured at the axial center of dual rings (2.1 mm axial, 1.8 mm tangential and radial). The MAMMI-PET has excellent spatial resolution and high sensitivity for primary breast cancer lesions. The results show performance improvement, especially in the absolute sensitivity, because of the more rings introduced in the MAMMI PET. The performance of the scanner and the validation results are considered to be reasonable enough to support its use in breast cancer imaging.