X-ray elastography: a novel approach to breast imaging

组织的机械性能，例如硬度，长期以来一直被认为是组织健康的重要指标。实际上，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。这种方法被称为弹性成像，比手动触诊更强大，因为临床医生能够可视化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，US），磁共振成像（MRI）和光学成像。基于US的弹性成像已经发展到能够用作常规乳腺癌诊断方案的一部分的程度。这些已建立的技术的问题之一是，当这些肿瘤位于体内时，它们分辨诸如小肿瘤的小特征的能力降低。例如，光学技术能够分辨小至0.02mm的特征，然而，只有当它们位于皮肤的约1mm内时。超声弹性成像可以检测到0.1mm以上的肿瘤，如果它们位于距离皮肤表面小于10cm，等等。我们建议使用最近开发的X射线成像技术，称为相位成像，它提供的生物组织的图像比传统的X射线成像清晰得多。使用这种技术，我们相信将有可能获得组织硬度的图像，分辨小至0.02mm的特征，位于体内深处，从而打破现有弹性成像技术的限制。虽然适用于一系列的应用程序，我们将这种技术应用于乳腺癌成像。如果成功的话，该技术可以应用于乳腺癌的筛查，诊断和治疗。特别是，它可以集成到一种称为断层合成的三维乳房X射线摄影中，为放射科医生提供一种额外的对比形式，以进行诊断。一旦在筛查阶段检测到可疑病变，该技术可用于后续成像，再次为放射科医生提供额外形式的对比，以进行诊断。最后，如果需要手术，可以使用这种技术来检查肿瘤是否在手术时被完全切除，而不是要求患者返回进行后续手术以切除任何剩余的肿瘤。

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.