Jhao-Ming Yu

Design and implementation of three-dimensional ring-scanning equipment for optimized measurements of near-infrared diffuse optical breast imaging

Abstract. We propose and implement three-dimensional (3-D) ring-scanning equipment for near-infrared (NIR) diffuse optical imaging to screen breast tumors under prostrating examination. This equipment has the function of the radial, circular, and vertical motion without compression of breast tissue, thereby achieving 3-D scanning; furthermore, a flexible combination of illumination and detection can be configured for the required resolution. Especially, a rotation-sliding-and-moving mechanism was designed for the guidance of source- and detection-channel motion. Prior to machining and construction of the system, a synthesized image reconstruction was simulated to show the feasibility of this 3-D NIR ring-scanning equipment; finally, this equipment is verified by performing phantom experiments. Rather than the fixed configuration, this addressed screening/diagnosing equipment has the flexibilities of optical-channel expansion for spatial resolution and the dimensional freedom for scanning in reconstructing optical-property images.

Design for source-and-detector configuration of a ring-scanning-based near-infrared optical imaging system

Abstract. The design scheme of the source-and-detector arrangement of a ring-scanning-based near-infrared optical imaging system prior to the mechanical and optical construction is demonstrated. In terms of the effectiveness and efficiency of design, through the computation of image reconstruction for varied imaging configurations, the influences of the source-and-detector arrangement on the resulting images are evaluated and a formula to estimate the scanning time is provided. The basic idea of our design is to divide circular scanning into several zones, each of which includes n sources and l detectors; i.e., m zones and n sources along with l detectors per zone are defined in the design. Comparison is made among different imaging configurations where their contrast-to-noise ratio measures are evaluated and contrast-and-size detail resolution curves are depicted. Results show that the 2Z3S or 3Z3S configuration is the optimal design in terms of the time consumption of a complete scanning and the resolution of reconstructed optical-property images.

Phantom verification for ring-scanning prostrate-type diffuse optical imaging system

We implemented a ring-scanning mechanism in a prostrate type for breast tumor detection. Reconstructed μa and μs′ images of multi-layers scanning are presented in good outcomes, showing it’s promising for the 3D scanning of breast.

Mammogram incorporated DOI with transmission and reflection parallel scanning

In this presentation, we demonstrate a working prototype of an optical breast imaging system using parallel-paddle architecture with dual-direction scanning, of which the designed module can be incorporated with a mammographic system for the acquisition of optical transmission and reflection information in both directions of up-down and down-up. Additionally, the scanning module enables to move with a designated pitch to accommodate varied breast size for acquiring adequate data to reconstruct the images. Currently, continuous-wave near infrared illumination modules are used for experimentation. The feasibility will be presented by phantom test.

Implementation of 3D prostrate ring-scanning mechanism for NIR diffuse optical imaging phantom validation

Diffuse optical imaging (DOI) providing functional information of tissues has drawn great attention for the last two decades. Near infrared (NIR) DOI systems composed of scanning bench, opt-electrical measurement module, system control, and data processing and image reconstruction schemes are developed for the screening and diagnosis of breast tumors. Mostly, the scanning bench belonging to fixed source-and-detector configuration limits computed image resolution to an extent. To cope with the issue, we propose, design and implement a 3D prostrate ring-scanning equipment for NIR DOI with flexible combinations of illumination and detection, and with the function of radial, circular and vertical movement without hard compression of breast tissue like the imaging system using or incorporating with X-ray mammographic bench. Especially, a rotation-sliding-and-moving mechanism was designed for the guidance of source- and detection-channel movement. Following the previous justification for synthesized image reconstruction, in the paper the validation using varied phantoms is further conducted and 3D image reconstruction for their absorption and scattering coefficients is illustrated through the computation of our in-house coded schemes. The source and detection NIR data are acquired to reconstruct the 3D images through the operation of scanning bench in the movement of vertical, radial and circular directions. Rather than the fixed configuration, the addressed screening/diagnosing equipment has the flexibility for optical-channel expansion with a compromise among construction cost, operation time, and spatial resolution of reconstructed μa and μs’ images.

Design and Fabrication of Prostrate Ring-Scanning Equipment for Near Infrared Diffuse Optical Imaging

Diffuse optical imaging (DOI) providing functional information of tissues has drawn great attention for the last two decades [1]. Near infrared (NIR) DOI systems composed of scanning equipment, opt-electrical measuring module, system control, and data processing and image reconstruction schemes are developed for the screening and diagnosis of breast tumors. Mostly, the scanning equipment belonging to fixed source-and-detector configuration limits computed image resolution to an extent [2–4]. To cope with the issue, a flexible ring-scanning mechanism design has been investigated and analyzed in order to obtain the most probable effectiveness and efficiency while retaining acceptable scanning time. Before the detail design of ring-scanning equipment was conducted, finite-element-based image reconstruction schemes were performed to obtain tomographical images through changing source-and-detection arrangement of the ring-scanning mechanism. From the simulation [5], the 2Z3S or 3Z3S configuration was found an apparently better design for the ring-scanning mechanism in terms of both the resolution of reconstructed opticalproperty images and the scanning time of equipment. Following the previous study, this technical brief demonstrates the design, fabrication, and test of the prototype ring-scanning equipment. 2 Methods

Design of 3D Ring-scanning Mechanism for NIR Diffuse Optical Imaging

We propose a 3D prostrate ring-scanning mechanism for NIR diffuse optical imaging with flexible combinations of illumination and detection, and with a function of radial-angular-and-vertical movement without compression of breast tissue.

Mammogram-based diffuse optical tomography

The study aims at developing an optical measurement module incorporated with an X-ray mammographic system to obtain diffuse optical images (DOI) for the detection of breast tumors. Two goals steer the study: (1) to enhance sensitivity and specificity of tumor detection through the use of functional DOI; and (2) to reduce radiation exposure by using only one mammogram, instead of two, as structure information to compute optical-coefficient images. A dual-direction (downward and upward) scanning device to project illuminated near infrared light with multiple-channel switching for both sources and detectors was designed and constructed to obtain double information. The designed and constructed NIR scanning module incorporates with GE Senographe 2000D to assist breast tumor detection.