Instrumentation and design of a frequency-domain diffuse optical tomography imager for breast cancer detection

Abstract

The instrument development and design of a prototype frequency-domain optical imaging device for breast cancer detection is described in detail. This device employs radio-frequency intensity modulated near-infrared light to image quantitatively both the scattering and absorption coefficients of tissue. The functioning components of the system include a laser diode and a photomultiplier tube, which are multiplexed automatically through 32 large core fiber optic bundles using high precision linear translation stages. Image reconstruction is based on a finite element solution of the diffusion equation. This tool for solving the forward problem of photon migration is coupled to an iterative optical property estimation algorithm, which uses a Levenberg-Marquardt routine with total variation minimization. The result of this development is an automated frequency-domain optical imager for computed tomography which produces quantitatively accurate images of the test phantoms used to date. This paper is a description and characterization of an automated frequency-domain computed tomography scanner, which is more quantitative than earlier systems used in diaphanography because of the combination of intensity modulated signal detection and iterative image reconstruction.

Concurrent MRI and diffuse optical tomography of breast after indocyanine green enhancement

“…Its main disadvantage remains the low spatial resolution achieved as a result of the highly scattering nature of tissue in the NIR. The resolution of current experimental DOT implementations (25,26) is Ϸ5 mm millimeters, although increased numbers of source-detector pairs and improved signal-to-noise may lead to further resolution improvement.…”

“…Thus far, DOT images of absorbing and scattering objects embedded in tissue-like media have been produced (2,(25)(26)(27)(28)(29)(30) by using phantoms. The experimental certainty of the phantom contrast makes the evaluation of the technique straightforward.…”

Diffuse optical tomography for breast cancer imaging guided by computed tomography: A feasibility study

“…[10][11][12][13][14] Most DOT breast imaging systems used fibers to deliver lasers to breast surface and collected the diffused light on the breast surface, in which the measurement number was determined by the optode pairings. 11,[15][16][17][18][19][20][21][22] To increase the number of measurement data, Culver et al reported a charge coupled device (CCD) camera based DOT imaging system. 23 Turner et al used a CCD camera to measure early photons in a DOT imaging system.…”

A near infrared instrument to monitor relative hemoglobin concentrations of human bone tissue in vitro and in vivo

“…NIRS instruments are of three main types based on the way they transmit signals and analyze the detected signals. 9 The types are continuous wave ͑cw͒, 2,10-16 frequency domain, 17,18 and time domain. 19 The instrument presented in this paper is a cw type instrument.…”