Detection of posteriorly located breast tumors using gold nanoparticles: A breast-mimicking phantom study

BACKGROUND: Accurately depicting breast tumors located posteriorly, close to the chest wall musculature, with conventional mammography is a technical challenge.

OBJECTIVE: This study demonstrates the proof of concept of an x-ray fluorescence mapping (XFM) technique to address this issue.

METHODS: A tissue-equivalent gel phantom is designed to mimic structures in the central part of a compressed breast. The posterior aspect of the breast and adjacent pectoralis major muscle are represented by another 10-mm-thickness breast tissue simulation phantom (BR12) that is attached to the back of the gel phantom as a region of interest (ROI). Two gold nanoparticle (GNP) solutions are embedded into the ROI to simulate varying GNP uptake within breast lesions. The ROI is imaged through performing the XFM technique with an x-ray pencil-beam and a single spectrometer.

RESULTS: A 2D mapping of the middle plane in the ROI demonstrates feasibility and matches well the known spatial distribution and different GNP concentrations. 3D reconstruction of the ROI is easily rendered by repeating the 2D mapping process.

CONCLUSION: XFM system geometry and its insensitivity to attenuation coefficients of breast tissue components are unique characteristics that may complement conventional mammography and improve the detection of breast cancers located posteriorly, adjacent to or overlying the chest wall musculature.