Ultrasonic modeling and measurements of cultured normal and malignant breast epithelial cells

Developing an in vivo ultrasonic detection method for cancer would be valuable for applications such as the real-time assessment of surgical margins during breast conservation surgery. To study the spectral signatures of normal and malignant mammary epithelial cells, computer simulations and laboratory measurements were performed on 2-D cell cultures. The simulations modeled the cell monolayers as arrays of spherical cells containing spherical nuclei. Multipole expansions and boundary conditions were used to solve for the acoustic scattering from each cell. Backscattered wave fields were summed at the transducer face to calculate the measured ultrasonic amplitude. The measurements used a high-frequency NDT pulser-receiver with a broadband, unfocused 50-MHz immersion transducer. Waveforms were acquired by immersing the transducer in the growth media of cell culture well plates and collecting the first reflection from the well bottoms. Simulated spectra and preliminary data indicated that a confluent cell monolayer was detectable at 75–100 MHz. To reduce variability in test results, an in situ monitoring system was designed to periodically collect ultrasonic waveforms inside a tissue culture incubator over several days without moving the well plate or transducer during monolayer growth. Results from these and other tests will be presented. [Work supported by NIH 5R21CA131798-02.]