A time-of-flight positron emission tomography (TOFPET) assembly for detecting lesions of a breast of a subject, wherein the subject may anatomically be defined with a median plane and chest wall-coronal plane. The assembly may comprise: a detector array having at least two or more detector segments. The detector segments may include: a scintillator for placement toward the target, the scintillator having a top edge generally closest to the subject and a detection surface wall aligned closest to surrounding the breast, a photo multiplier opposite the scintillator, and a readout connected to the photo multiplier. The assembly may also comprise a processor that receives the acquired tracer emission signals and converts the signals into a three dimensional, tomographic image reconstruction. The detector array is defined by a ring surrounding the breast and the face of ring that may be tilted to offset the chest wall-coronal plane of the subject, and wherein one of the top edges of one of the detector segments is above the chest wall-coronal plane of the subject in the posterior direction.
