Breast cancer is the second most prevalent cancer in women, with a mortality rate of 40,000 per year in the US. However, if detected and treated early, more than 95% of breast cancer patients will survive. Current method for breast cancer detection relies heavily on X-ray mammography, which produces many false positive findings. These false positive readings cause substantial mental anguish in patients and in many cases, costly and painful biopsies. A full 80% of all biopies uncover only benign masses and calcifications at an estimated annual cost of 2.5 billion dollars. To improve breast cancer detection, we propose a highly innovative design for a dedicated Positron Emission Mammography (PEM) camera utilizing long, linear, lead-walled straw (LWS) detectors that provide high spatial resolution and rigorously accurate depth of interaction determination. Thus detectors with ample field of view to contain the entire breast without translation can be employed and very close detector pair spacing can be used without resolution degradation. Our proposed camera offers markedly increased sensitivity and resolution with substantially reduced cost compared to crystal-based PEM cameras under development. Phase I of the project will achieve proof of concept by constructing and testing two substantial submodules of a full scale camera. In Phase II, a full scale high sensitivity prototype camera will be constructed and tested. ? ?