Large scale medical image search technology - a proof of concept

放射治疗是治疗癌症的一种关键方法，在这种方法中，高能辐射直接照射肿瘤，破坏DNA复制，从而摧毁肿瘤。然而，在这个过程中，周围的健康组织也不可避免地受到辐射。因此，有必要计划任何治疗，以最大限度地提高肿瘤剂量，同时最小化对健康组织的剂量。在这个过程中，被称为RT计划，临床专家团队在实施之前花费大量时间制定治疗计划。这个过程非常耗时，通常需要几十个小时，导致成本高，诊所的吞吐量有限。计划过程中的一个重要步骤是在患者的医学图像扫描中描绘肿瘤和周围健康器官，这一任务被称为轮廓。由此产生的描述，称为RTstructures，随后用于估计剂量和优化治疗计划。通常，肿瘤和器官的描绘是一个费力的手工过程。一种称为基于阿特拉斯的轮廓的图像处理技术已被证明可以有效地加快这一步骤。在这里，健康器官的专家描绘的例子扫描，被称为地图集，被自动扭曲到病人的扫描。然而，已经发现这种方法仅在患者解剖结构与寰椎外观相似的情况下有效。这个概念验证项目的目的是使基于图谱的轮廓准确地为大多数（如果不是所有）患者工作。我们将通过开发创新技术来实现这一目标，该技术可以建立并快速搜索包含数千个代表人体解剖学广泛变化的示例描绘的大型地图集数据库。在类似于网络关键词搜索的过程中，当应用于新患者时，系统将首先从数据库中检索最匹配的病例，并仅使用这些病例进行基于地图集的轮廓处理。

Radiotherapy is a key method for treating cancer in which high energy radiation is directed at a tumour to disrupt DNA replication and thereby destroy the tumour. However in the process, it is inevitable that surrounding healthy tissue is also irradiated. It is therefore necessary to plan any therapy to maximise the tumour dose while minimising the dose to the healthy tissue.In this process, known as RT planning, teams of clinical experts spend a great deal of time developing a treatment plan prior to its administration. This process is very time consuming and can typically take some tens of hours, leading to high costs and limited throughput for the clinic.A major step in the planning process is the delineation of the tumour and surrounding healthy organs in a medical image scan of the patient, a task known as contouring. The resultant delineations, called RTstructures, are subsequently used to estimate the delivered dose and optimise the treatment plan. Typically, tumour and organ delineation is a laborous manual process.An image processing technique known as atlas-based contouring has been shown to be effective in speeding up this step. Here, expert delineations of healthy organs on an example scan, known as an atlas, are warped automatically onto the scan of the patient. However, it has been found that this method is effective only in cases where the anatomy of the patient is similar in appearance to the atlas.The aim of this proof-of-concept project is to make atlas-based contouring work accurately for most if not all patients. We will do this by developing innovative technology that can build and rapidly search large-scale databases of atlases containing thousands of example delineations representing the wide variability in human anatomy. In a process analogous to Web search of keywords, when applied to a new patient, the system will first retrieve the best matching case or cases from the database and use only those for the atlas-based contouring process.