3-D redatuming for breast ultrasound

Breast cancer is the most common form of cancer diagnosed with women. To reduce its mortality rate, early diagnosis is important. In the past, this has led to the introduction of national screening programs using mammography. The disadvantages of mammography (application of ionizing radiation and low detection rate in dense breast) resulted in the demand for an alternative. This demand has led to the development of ultrasonic water bath scanning systems. Those systems scan the breast from all sides and aim for reconstructing the acoustic tissue properties from the measured pressure fields by employing among others full-waveform inversion methods. However, full-wave inversion is computationally expensive, especially in 3-D, and scales almost linear with the size of the spatial domain. To reduce the computational load, we propose a method that reduces the size of the spatial computational domain by back-propagating the field measured on the surface of the 3-D scanning geometry to a surface enclosing a reduced volume. To this end, the measured field is first decomposed into spherical Hankel functions with complex coefficients and subsequently redatumed to a new surface closer by the object. The proposed redatuming method is tested successfully for 3-D synthetic examples.