Detection of prostate cancer with optoacoustic tomography: Feasibility and modeling

A laser optoacoustic imaging system (LOIS) with a transrectal probe might become useful for detection of prostate cancer, for guidance of prostate biopsies, and for monitoring of therapy for prostate cancer. Two main components of a prostate optoacoustic imaging system were examined in the feasibility study reported here. (1) The optical contrast between cancerous tissues and normal or benign tissues in the prostate in a surgically removed prostate specimen was tested with a LOIS originally designed for breast imaging. These pilot imaging studies demonstrated that there is sufficient optoacoustic tissue contrast for tumor detection in a prostate with an advanced carcinoma. (2) A computer model of a miniature array of optoacoustic transducers sensitive to an ultrawide band of ultrasonic frequencies was developed and used for evaluation of detector arrays of various different configurations and dimensions. We considered the importance of the number of transducer elements in the array, the thickness of the piezoelectric polymer film, poly(vinylidene fluoride) in each transducer, and the overall geometry of the array. Imaging with an axial resolution of better than 200 μm will be possible. The lateral resolution will be 0.5 mm to 1 mm, depending on the field of view. These results are being used in the construction of a working probe for optoacoustic imaging of the prostate.