A dedicated PET system for breast imaging (CYBPET)

Early detection of breast cancer is very important for efficient and effective treatment. Conventional whole body PET (WB-PET) scanners provide metabolic images of breast cancer with several shortcomings related to the general-purpose nature of these systems. We propose a Cylindrical Breast PET (CYBPET) system for breast imaging, for the patients in the prone position. An individual pendulous breast is covered by a thin plastic to make a mild pressure and surrounded by the crystals inside the CYBPET ring and will positioned in the center of field of view. Each breast is imaged separately. The rest of the body has been shielded properly to minimize the contribution of scattered photons from the other breast and the rest of the body. This proposed system configuration has several advantages over the WB-PET system configuration for breast imaging, namely: I) greatly reduced attenuation and scattering effects in breast imaging; II) reduced interference from activity in parts the torso in the FOV; III) elimination a separate attenuation scan due to the homogeneity of breast; IV) reduced number of detectors and its´ related electronics to reduce the price of the system. Before building the CYBPET instrument, we have simulated it using the PETSIM Monte Carlo program. Simulations of CYBPET and a (WB-PET) for a 8 mm tumor inside the breast with a lesion to background activity concentration of 10 to 1 were made. The NECR (max) for CYBPET (WB-PET) were 203(184) (kcps) in the activity concentration of 3.2(10.4) (μCi/cc). Also the coincidence efficiency show the amounts of 470 and 132 (kcps /μCi/cc) for CYBPET and WB-PET respectively. These results and the advantages listed above suggest improved lesion visualization in the early disease stages. The only shortcoming, like the PEM, SPEM and mammography systems is, this system would not be able to detect the lesions which are very close to chest wall.