Miniaturized optical fiber probe for prostate cancer screening

Abstract

Tissue elasticity is universally recognized as a diagnostic and prognostic biomarker for prostate cancer. As the first diagnostic test, the digital rectal examination is used since malignancy changes the prostate morphology and affects its mechanical properties. Currently, this examination is performed manually by the physician, with an unsatisfactory positive predictive value of 42%. A more objective and spatially selective technique is expected to provide a better prediction degree and understanding of the disease. To this aim, here we propose a miniaturized probe, based on optical fiber sensor technology, for mechanical characterization of the prostate with sub-millimeter resolution. Specifically, the optical system incorporates a customized Fiber Bragg Grating, judiciously integrated in a metallic cannula and moved by a robotic arm. The probe enables the local measurement of the force upon tissue indentation with a resolution of 0.97 mN. The system has been developed in such a way to be potentially used directly in vivo. Measurements performed on phantom tissues mimicking different stages of the prostatic carcinoma demonstrated the capability of our device to distinguish healthy from diseased zones of the prostate. The study on phantoms has been complemented with preliminary ex vivo experiments on real organs obtained from radical surgeries. Our findings lay the foundation for the development of advanced optical probes that, when integrated inside biopsy needle, are able to perform in vivo direct mechanical measurements with high sensitivity and spatial resolution, opening to new scenarios for early diagnosis and enhanced diagnostic accuracy of prostate cancer.

Optical fiber probe for prostate cancer screening: ex vivo study

“…A calibration procedure has been developed to find the correlation factor between the optical probe wavelength shift and the force applied on its tip. The probe sensitivity (Δλ/ΔN) was found to be 1031 pm/N, details are provided in ref [8]. The sensor resolution is thus estimated to be 0.97 mN that is the ratio between the sensitivity (1031 pm/N) and the interrogator resolution (1 pm).…”

“…The functionality of the developed sensor was previously assessed by means of different tests carried out on silicone membranes, phantom tissues mimicking different stages of the prostatic carcinoma, and also preliminary ex vivo experiments on real organs (healthy and unhealthy prostates) obtained from radical surgeries [8]. Here we carried out a further ex vivo study on three real prostates with different stages of the carcinoma (Gleason score from 6 to 8).…”

Optical Biomedical Diagnostics Using Lab-on-Fiber Technology: A Review

“…A peptide nucleic acid and gold nanoparticles (AuNPs) enhanced detection scheme based on MOFs based Bragg grating is shown in Figure 10 [80]. Recently, an FBG based biosensor for the early diagnosis of prostate cancer screening has been reported by Iele et al [81]. The miniaturized sensor probe was fabricated by integrating a customized FBG within metallic cannula and moved to various places of the prostate using an automated arm.…”

A cable driven robotic palpation system with contact force sensing based on cable tension observation

“…Robotic palpation systems can provide objective and quantitative information for the better understanding of the underlying morphological changes in the tissues using mechanical properties as potential biomarkers for tumours. In addition to the methods mentioned above, elastography and indirect modalities based on optical fibres have also been explored in the assessment of mechanical characteristics of the prostate tissue 12–16 …”

“…In addition to the methods mentioned above, elastography and indirect modalities based on optical fibres have also been explored in the assessment of mechanical characteristics of the prostate tissue. 12 , 13 , 14 , 15 , 16 …”