Study of trans-rectal near-infrared diffuse optical tomography concurrent with trans-rectal ultrasound for prostate imaging

Abstract

Scope and Method of Study:

The objective of this study is to develop an endo-rectal NIR imaging probe coupled with TRUS in sagittal plane. The successful outcome of this research will find a way to improve the imaging contrast and help radiologists to locate the suspicious lesions in prostate which will ultimately improve the biopsy accuracy.

The combined system using an endo-rectal near-infrared (NIR) applicator integrated with a trans-rectal ultrasound (TRUS) probe is demonstrated. A continuous-wave (CW) NIR optical tomography system is integrated with a commercial US scanner to form the dual-modality imager. Sagittal trans-rectal imaging is performed concurrently by endo-rectal NIR and TRUS.

Findings and Conclusions:

The TRUS coupled trans-rectal NIR sagittal imaging probe is fabricated. The CW optical measurement demonstrated the quantitative estimation of the optical absorption coefficient is feasible when incorporating the TRUS a priori information. The use of condom is found to have minimum effects on NIR tomography measurement. Absorptive targets can also be recognized by optical stand-alone reconstruction which demonstrates the potential of finding targets ambiguous to US imaging.

In-vivo imaging of normal canine prostate and TVT tumors in the canine pelvic canal was performed by trans-rectal NIR tomography coupled with TRUS. The TVT tumor nodules were presented as hyper-absorption and hyper-scattering with respect to the normal prostatic and other pelvic tissues. Correlation of the TVT locations is found between trans-rectal NIR and TRUS images.

Dual-band in-vivo imaging of canine prostate with TVT tumors demonstrated a non-invasive optical measurement of [HbT] changes associated with tumor development. Using trans-rectal US-coupled spectral optical tomography the development and lateral involvement of the prostate cancer was detected earlier than using TRUS alone.