In vivo trans-rectal ultrasound coupled trans-rectal near-infrared optical tomography of canine prostate bearing transmissible venereal tumor

Abstract

In vivo trans-rectal near-infrared (NIR) optical tomography is conducted on a tumor-bearing canine prostate with the assistance of trans-rectal ultrasound (TRUS). The canine prostate tumor model is made possible by a unique round cell neoplasm of dogs, transmissible venereal tumor (TVT) that can be transferred from dog to dog regardless of histocompatibility. A characterized TVT cell line was homogenized and passed twice in subcutaneous tissue of NOD/SCID mice. Following the second passage, the tumor was recovered, homogenized and then inoculated by ultrasound guidance into the prostate gland of a healthy dog. The dog was then imaged with a combined trans-rectal NIR and TRUS imager using an integrated trans-rectal NIR/US applicator. The image was taken by NIR and US modalities concurrently, both in sagittal view. The trans-rectal NIR imager is a continuous-wave system that illuminates 7 source channels sequentially by a fiber switch to deliver sufficient light power to the relatively more absorbing prostate tissue and samples 7 detection channels simultaneously by a gated intensified high-resolution CCD camera. This work tests the feasibility of detecting prostate tumor by trans-rectal NIR optical tomography and the benefit of augmenting TRUS with trans-rectal NIR imaging.

Diffuse optical tomography to monitor the photocoagulation front during interstitial photothermal therapy: Numerical simulations and measurements in tissue-simulating phantoms

“…It is also apparent that optimizing the probe design for this specific clinical application is critical in order to achieve personalized treatment delivery, and is likely different from the design for whole prostate tomography as used for cancer detection [24].…”

“…The experimentally tested configuration was originally designed for whole prostate imaging [23][24][25]. With its large field of view, lesion monitoring is relatively insensitive to probe placement.…”

“…The phantom experiments carried out for cross-validation with the simulations used a CW-TRDOT system that has been previously reported by Piao and colleagues [24] for in vivo canine prostate cancer imaging studies. The source and detector fibers are mounted on a near-flatface substrate attached to a cylindrical 2 cm diameter ultrasound probe.…”

“…Of particular relevance here is a system that combined continuous-wave (CW) transrectal diffuse optical tomography (CW-TRDOT) with twodimensional (2-D) TRUS for prostate cancer detection and quantification, based on the tumor having higher optical absorption than normal prostate in the NIR [23][24][25]. Tumor imaging was successfully demonstrated in a canine prostate cancer model [24] using this system. In the context of thermal therapy, the tissue optical scattering typically increases by 2-to 5-fold upon coagulation due to changes in tissue cell density and protein denaturation, as shown in several studies [26][27][28][29][30].…”

“…A variety of DOT systems have been reported for functional imaging or tumor detection, including in the breast [18][19][20] and brain [21,22]. Of particular relevance here is a system that combined continuous-wave (CW) transrectal diffuse optical tomography (CW-TRDOT) with twodimensional (2-D) TRUS for prostate cancer detection and quantification, based on the tumor having higher optical absorption than normal prostate in the NIR [23][24][25]. Tumor imaging was successfully demonstrated in a canine prostate cancer model [24] using this system.…”