Development and evaluation of a robust algorithm for computer-assisted detection of sentinel lymph node micrometastases.

Aims: Increasing the sectioning rate for breast sentinel lymph nodes can increase the likelihood of detecting micrometastases. To make serial sectioning feasible, we have developed an algorithm for computer-assisted detection (CAD) with digitized lymph node sections.

Methods And Results: K-means clustering assigned image pixels to one of four areas in a colourspace (representing tumour, unstained background, counterstained background and microtomy artefacts).

Increasing specimen coverage using digital whole-mount breast pathology: implementation, clinical feasibility and application in research.

Conventional histopathological evaluation is performed on breast specimens using a highly limited sampling of tissues visualized in a two-dimensional (2D) manner although important tumor measurements are three-dimensional. Here we describe a '3D' technique for whole-mount, whole-specimen processing which reduces conformational change and dramatically increases specimen coverage, based on digitizing whole-specimen, whole-mount (up to 12.7cm×17.

Screen-film mammographic density and breast cancer risk: a comparison of the volumetric standard mammogram form and the interactive threshold measurement methods.

Background: Mammographic density is a strong risk factor for breast cancer, usually measured by an area-based threshold method that dichotomizes the breast area on a mammogram into dense and nondense regions. Volumetric methods of breast density measurement, such as the fully automated standard mammogram form (SMF) method that estimates the volume of dense and total breast tissue, may provide a more accurate density measurement and improve risk prediction.

Methods: In 2000-2003, a case-control study was conducted of 367 newly confirmed breast cancer cases and 661 age-matched breast cancer-free controls who underwent screen-film mammography at several centers in Toronto, Canada.

Mammographic density and breast cancer risk: evaluation of a novel method of measuring breast tissue volumes.

Background: Mammographic density has been found to be strongly associated with risk of breast cancer. We have assessed a novel method of assessing breast tissue that is fully automated, does not require an observer, and measures the volume, rather than the projected area, of the relevant tissues in digitized screen-film mammogram.

Methods: Sixteen mammography machines in seven locations in Toronto were calibrated to allow the estimation of the proportion of radiologically dense (stromal and epithelial tissue) and nondense (fatty) tissue represented in each pixel of the mammographic image.

Accurate estimation of compressed breast thickness in mammography.

The determination of volumetric breast density (VBD) from mammograms requires an accurate knowledge of the thickness of the compressed breast. Previously, the authors described a technique for measuring local thicknesses using optical stereoscopic photogrammetry [A. H.

Optical imaging analysis of microscopic radiation dose gradients in Gafchromic EBT film using a digital microscope.

By providing superior localization and immobilization, stereotactic radiosurgery (SRS) is capable of delivering millimeter spheres of dose to intracranial targets with submillimeter precision. Several authors have proposed new SRS solutions to dramatically reduce beam penumbra to hundreds of microns. These solutions require new quality assurance methods capable of penumbra measurement at the micron scale.

Spatial resolution requirements for acquisition of the virtual screening slide for digital whole-specimen breast histopathology.

We examined the effect of lateral spatial resolution and reader specialty on the accuracy of detection of breast cancer. The motivation for this pilot study was the need to acquire and display very large data sets in whole-specimen 3D digital breast histopathology imaging. The ultimate goal is to determine the minimum resolution adequate for detection of malignancy.

Design and characterization of a digital image acquisition system for whole-specimen breast histopathology.

We have developed a digital histopathology imaging system capable of producing a three-dimensional (3D) representation of histopathology from an entire lumpectomy specimen. The system has the potential to improve the accuracy of surgical margin assessment in the treatment of breast cancer by providing finer sampling and 3D visualization. A scanning light microscope was modified to allow digital photomicrography of a stack of large (up to 120x170 mm2) histology slides cut serially through the entire specimen.