POSITRON emission tomography (PET) is used in assessing therapy response, staging, and restaging of breast cancer . However, whole-body PET scanners are not ideally suited to breast imaging due to low geometric sensitivity, low spatial resolution and signal loss due to attenuation in the body. Several groups are working on dedicated breast imaging systems to overcome such limitations. Due to the typically smaller field of view (FOV), detectors capable of measuring depth of interaction (DOI) can yield better performance in dedicated breast PET scanners. A high resolution positron emission tomography/computed tomography (PET/CT) scanner that uses DOI encoding detectors and is dedicated for human breast imaging is currently been developed in our laboratory. This paper presents the design and implementation of a prototype of the PET component of the aforementioned scanner.