Abstract
A significant number of patients receiving breast-conserving surgery (BCS) for invasive carcinoma and ductal carcinoma in situ (DCIS) may need reoperation following tumor-positive margins from final histopathology tests. All current intraoperative margin assessment modalities have specific limitations. As a first step towards the development of a compact system for intraoperative specimen imaging based on edge illumination x-ray phase contrast, we prove that the system’s dimensions can be reduced without affecting imaging performance.We analysed the variation in noise and contrast to noise ratio (CNR) with decreasing system length using the edge illumination x-ray phase contrast imaging setup. Two-(planar) and three-(computed tomography (CT)) dimensional imaging acquisitions of custom phantoms and a breast tissue specimen were made. Dedicated phase retrieval algorithms were used to separate refraction and absorption signals. A ‘single-shot’ retrieval method was also used, to retrieve thickness map images, due to its simple acquisition procedure and reduced acquisition times. Experimental results were compared to numerical simulations where appropriate.The relative contribution of dark noise signal in integrating detectors is significant for low photon count statistics acquisitions. Under constant exposure factors and magnification, a more compact system provides an increase in CNR. Superior CNR results were obtained for refraction and thickness map images when compared to absorption images. Results indicate that the ‘single-shot’ acquisition method is preferable for a compact CT intraoperative specimen scanner; it allows for shorter acquisition times and its combination of the absorption and refraction signals ultimately leads to a higher contrast. The first CT images of a breast specimen acquired with the compact system provided promising results when compared to those of the longer length system.
Highlights
In light of the limitations of the above methods and the need to reduce re-excision rates, several new technologies have been developed over recent years
As a first step towards the development of a compact system for intraoperative specimen imaging based on edge illumination X-ray phase contrast, we prove that the system’s dimensions can be reduced without affecting imaging performance
It can be seen that initial simulations, not accounting for the presence of dark noise signal (DNS) in integrating detectors, did not match the experimental results
Summary
In light of the limitations of the above methods and the need to reduce re-excision rates, several new technologies have been developed over recent years. Raman spectroscopy (Kong et al 2014) and optical coherence tomography (Nguyen et al 2009) have reported high sensitivity and specificity values, these assessment methods suffer from long image acquisition times, limited depth penetration, artefacts from cauterised tissue and penetration of dyes into healthy tissue. These methods are not volumetric and only allow to probe the specimen at specific locations making the probing of the entire margin difficult. Due to the unique signature of each cell type, further validation is required to assess its diagnostic accuracy with more rare cancer types
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call