Photoacoustic imaging(PA)is an emerging hybrid technique that is capable of resolving both structural and functional information(tissue oxygenation,hemoglobin level,etc.)centimeter deep in the tissue with submillimeter resolution.In this study,we aim to use PA imaging for the assessments of placental oxygenation,which reflects the early signs of placental hypoperfusion and the onset of tissue hypoxia.A tissue mimicking blood phantom with blood sample filled in the polyethylene tubes(PE50)was used to the test the sensitivity and accuracy of the VEVO LAZR PA imaging system for oxygenation measurement.