Development of a continuous-wave dual-band trans-rectal optical tomography system for concurrent sagittal imaging with trans-rectal ultrasound

摘要

A dual-band trans-rectal optical tomography system is constructed based on an endo-rectal near-infrared/ultrasound applicator that has been developed previously in our laboratory. The endo-rectal NIR/US applicator consists of a commercial bi-plane ultrasound and a NIR probe attached to the sagittal ultrasound transducer. The NIR probe consists of 7 illumination & 7 detection channels that are distributed in parallel to and aside the sagittal TRUS transducer. The emissions from a 780nm and an 830nm light sources are combined and delivered sequentially to the 7 NIR source channels of the endo-rectal NIR/US probe. The 7 NIR detection channels are coupled to a spectrometer for separation of the signals at two wavelengths illuminated from single source channel. The dual-band signals from all source channels are acquired sequentially by a CCD camera synchronized with the source switching. The acquisition of dual-band trans-rectal optical tomography data is accompanied by position-correlated concurrent trans-rectal ultrasound imaging. The reconstruction of a target at dual-wavelength illumination is guided by a priori spatial information provided by the sagittal trans-rectal ultrasound. Liquid phantoms with different hemoglobin concentration and oxygen saturation are used to test the feasibility of dual-band trans-rectal optical tomography.