MAP-EM reconstruction using uniform background template for limited-angle PEM

Positron emission mammography (PEM) with a partial detector ring is now under development. Due to limited angle coverage, an incomplete sampling produces artifacts in reconstruction images resulting in reduction of signal-to-noise ratio. We then developed a MAP-EM reconstruction method using uniform background template for PEM imaging. Since the image can be modeled as the sum of a uniform background image and a spot image consisting of hot lesions, the method first creates a template image simulating a uniform background image from a breast contour. L0 distance between the template image and the reconstructed image is incorporated into the cost function for image reconstruction. Our simulation study demonstrated that the proposed method provides distortion and artifact free images even with a limited angle PEM scanner. With estimating a uniform template image, one can avoid the need for MRI or CT scans as well as TOF information in order to achieve improvements in lesion detectability.