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In this study, we proposed and implemented a ring-scanning mechanism in the prone position for application in breast tumour detection. The current scanning module using two zones with three light sources in each zone enables the acquisition of 36 source and 30 detection data (36S × 30D) items during the optical information collection phase. This study employed only three photomultiplier tubes (PMTs), instead of 30 PMTs used in a fixed model. In particular, the circular scanning of source-and-detection module actually behaves as more channels and can acquire more optoelectrical data as the scanning module operates in a fractional motion of a single channel-to-channel span. In this study, the optoelectrical measurement system was first calibrated; then, the feasibility of optical-coefficient image reconstruction was verified using several heterogeneous cylindrical phantoms. The reconstructed μ a and μ s ′ images through multilayer scanning presented good outcomes, implying that the developed system is promising for 3D scanning of breasts. In a quantitative analysis, the contrast-to-noise ratios of the μ a and μ s ′ images (6.00 and 4.97, respectively) for the flexible scanning scheme were superior to those derived for the fixed scheme (5.05 and 4.31, respectively). This indicates that the higher amount of detection information obtained through the proposed scanning module can enhance the spatial resolution of the reconstructed images while retaining an acceptable scanning time.

Diffuse optical imaging enables to reconstruct distribution of optical properties, absorption and scattering coefficients, in tissue for breast cancer detection based on diffusion equation with the help of the initial guess obtained from measured data. To estimate the initial guess of the optical-property coefficients, an analytical solution of diffusion equation can be used and compared with the measured data. The analytical solution for a homogeneous infinite medium can be obtained in the frequency domain, expressing that the photon intensity and the phase lag relative to the distance between source and detector in a linear relationship. In this study, a succinct calculation using the trigonometric relation is proposed to estimate the optical-property coefficients. A tank-type and a cylinder Lipovenoes phantoms with two concentrations of 1.25% and 2.5% are employed and measured for verification. It is found that the method proposed here shows better results and results in estimation errors of 0–14.81% for μa and 20–42% for μs′.

A working prototype of an optical breast imaging system involving a dual-direction parallel-plate scanning scheme in combination with a mammography machine was demonstrated and applied in imaging healthy and malignant breasts in a clinical environment.

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.

Breast tissues like fatty and fibroglandular ones are adipose mainly and possess high scattering nature, so that they diffuse and make the light approximately uniformly distribute over the measured cross-section besides absorbing to reduce the light intensity. Strong cause-and-effect relationships exist between absorption and intensity decay, and between scattering and phase delay as well. Thereby in a diffuse optical imaging system it is a general practice to estimate absorption coefficients from the measured intensity since it reflects most of the absorption property. This study aims to illustrate that both μ a and μ ′ images of breast can be reconstructed by only direct-current data reliably to a certain extent. Varied sets of phantom design with assigned absorption/scattering properties for inclusion and background were synthesized and image reconstructed to demonstrate this perspective. Moreover, we employed a slab-type diffuse optical imaging system with a dual-direction direct-current NIR measurement module, where reconstructed images were compared between with and without reflectance NIR data.

Diffuse optical imaging (DOI) is emerging as a new functional imaging modality that can be used for breast cancer screening. Due to the ill-posed inverse problem for DOI image reconstruction, regularization is essential to remedy such a drawback. In our previous study, we have successfully implemented edge-preserving regularization into image reconstruction algorithm for improving the reconstructed images. In this study, we incorporate additional anatomical image, which can be obtained from other imaging modality such as mammography or magnetic resonance imaging, although showing no tumor information, into edge-preserving regularization for further improving the reconstructed images. Reconstruction results show that the quality of reconstructed images can be significantly improved.

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 μ a and μ s ’ images.

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.

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.

Comparison is made among several different imaging configurations in order to evaluate how the source-and-detector arrangement affects the resulting image. Results show that the 3Z1S design is the optimal design for the scanning mechanism.

System verification and the reconstructed optical-property images of breast-like phantoms and biological tissue are presented using a ring-scanning-based imaging system of frequency-domain near infrared diffuse optical tomography with a high degree of spatial flexibility.

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.

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.