X-ray elastography: a novel approach to breast imaging

长期以来，组织的机械性能，如硬度，一直被认为是组织健康的重要指标。事实上，临床医生经常使用手动触诊作为常规诊断程序的一部分。为了获得组织硬度的二维和三维图像，已经开发了一系列技术。这种称为弹性成像的方法比人工触诊要强大得多，因为临床医生能够可视化身体内组织的位置和相对硬度。现有的弹性成像技术基于超声成像(即，超声，美国)、磁共振成像(MRI)和光学成像。基于美国的弹性成像已经发展到能够作为常规乳腺癌诊断方案的一部分。这些现有技术的问题之一是，它们解决小特征(如小肿瘤)的能力下降，因为这些肿瘤位于体内。例如，光学技术能够分辨小到0.02 mm的特征，然而，只有当它们位于大约1 mm的皮肤范围内时。如果肿瘤距离皮肤表面不到10厘米，就可以使用超声弹性成像技术检测到大小超过0.1 mm的肿瘤。我们建议使用最近开发的X射线成像技术，称为相位成像，它提供的生物组织图像比传统的X射线成像要清晰得多。使用这项技术，我们相信将有可能获得组织硬度的图像，分辨率小至0.02 mm的特征，位于身体深处，从而打破现有弹性成像技术的限制。虽然适用于一系列应用，但我们将把这项技术应用于乳腺癌成像。如果成功，该技术可以应用于乳腺癌的筛查、诊断和治疗。特别是，它可以被整合到一种名为断层合成的三维乳房X光摄影中，为放射科医生提供另一种对比形式，以进行诊断。一旦在筛查阶段发现可疑病变，这项技术就可以用于后续成像，再次为放射科医生提供另一种形式的对比以进行诊断。最后，如果需要手术，可以使用这项技术来检查肿瘤在手术时是否已经完全切除，而不是要求患者返回进行后续手术以移除任何剩余的肿瘤。

The mechanical properties of tissue, such as stiffness, have long been known to be an important indicator of the health of tissue. Indeed, manual palpation is used regularly by clinicians as part of routine diagnostic procedures. A range of techniques have been developed in order to obtain images, both in two and three dimensions, of tissue stiffness. This approach, known as elastography, is significantly more powerful than manual palpation as the clinician is able to visualise the location, and relative stiffness, of tissue within the body.Existing elastography techniques are based on ultrasonoghraphic imaging (i.e. ultrasound, US), magnetic resonance imaging (MRI) and optical imaging. US based elastography has developed to the point where it is able to be used as part of a routine breast cancer diagnosis protocols. One of the problems with these established techniques is that their ability to resolve small features, such as small tumours, degrades as these tumours are located within the body. For example, optical techniques are able to resolve features as small as 0.02mm, however, only if they are located within about 1mm of the skin. Tumours over 0.1mm in size can be detected using US elastography if they are located less than 10cm from the skin surface, and so on.We propose to make use of a recently developed X-ray imaging technique, known as phase imaging, which provides images of biological tissue which are much clearer than conventional X-ray imaging. Using this technique we believe it will be possible to obtain images of tissue stiffness, resolving features as small as 0.02mm, located deep within the body, thus breaking the limitation of existing elastography techniques. Although applicable to a range of applications, we will apply this technique to breast cancer imaging. If successful, the technique could be applied in screening, diagnosis and treatment of breast cancer. In particular, it could be integrated into a form of three-dimensional mammography known as tomosynthesis, giving the radiologist an additional form of contrast upon which to make their diagnosis. Once a suspicious lesion has been detected at the screening stage, this technique could be used in follow up imaging, again to provide the radiologist with an additional form of contrast upon which to make their diagnosis. Finally, if surgery is required, it may be possible to use this technique to check that the tumour has been completely removed at the time of surgery, rather than requiring a patient to return for follow-up surgery to remove any remaining tumour.