Dynamic X-ray elastography using a pulsed photocathode source

Chika Kamezawa,Avilash Cramer,Wataru Yashiro,Kazuyuki Hyodo,Wolfgang Krull,Rajiv Gupta

doi:10.1038/s41598-021-03221-y

Abstract

X-ray absorption of breast cancers and surrounding healthy tissue can be very similar, a situation that sometimes leads to missed cancers or false-positive diagnoses. To increase the accuracy of mammography and breast tomosynthesis, we describe dynamic X-ray elastography using a novel pulsed X-ray source. This new imaging modality provides both absorption and mechanical properties of the imaged material. We use a small acoustic speaker to vibrate the sample while a synchronously pulsed cold cathode X-ray source images the mechanical deformation. Using these stroboscopic images, we derive two-dimensional stiffness maps of the sample in addition to the conventional X-ray image. In a breast phantom composed of ZrO2 powder embedded in gel, dynamic elastography derived stiffness maps were able to discriminate a hard inclusion from surrounding material with a contrast-to-noise ratio (CNR) of 4.5. The CNR on the corresponding absorption image was 1.1. This demonstrates the feasibility of dynamic X-ray elastography with a synchronously pulsed X-ray source.

Highlights

X-ray absorption of breast cancers and surrounding healthy tissue can be very similar, a situation that sometimes leads to missed cancers or false-positive diagnoses
Depending on the sample of interest, a number of different medical imaging techniques may be employed to image the shear wave. Both magnetic resonance (MR) and ultrasound (US) elastography have rapidly expanded into clinical practice and have been used for liver and breast diseases, r espectively[11,12,13]
We demonstrated two-dimensional dynamic X-ray elastography by applying pneumatic vibration to a Hitohada gel phantom

Summary

Introduction

X-ray absorption of breast cancers and surrounding healthy tissue can be very similar, a situation that sometimes leads to missed cancers or false-positive diagnoses. To increase the accuracy of mammography and breast tomosynthesis, we describe dynamic X-ray elastography using a novel pulsed X-ray source This new imaging modality provides both absorption and mechanical properties of the imaged material. Static elastography using X-ray imaging has been reported by Hamilton et al.[18], Kim et al.[19, 20], and Sutphin et al.[21] As mentioned before, these static techniques do not provide a quantitative elasticity map. We recently reported on dynamic X-ray elastography[22] that provides a two-dimensional map of storage and loss moduli This prior study used a continuous X-ray source that was divided into individual pulses using an optical chopper wheel, an arrangement that was somewhat cumbersome to implement and difficult to accurately time.

Methods

Results

Conclusion