Transurethral Shear Wave Elastography (TU-SWE) for Prostate Cancer Diagnosis

前列腺癌（PCa）是英国男性最常见的癌症。它也是仅次于肺癌的第二大癌症死亡原因。它约占所有癌症病例的13%，占英国所有癌症死亡人数的7%。PCa的发病率随年龄增长而增加，主要影响50岁以上的男性。当血清前列腺特异性抗原（PSA）升高或直肠指检异常时，常怀疑前列腺癌。然而，PSA筛查导致大量不需要立即治疗的非癌症或惰性癌症患者进行不必要的活检。尽管PSA检测的特异性较低，并且在阴性系统活检后存在不确定性，但这些技术仍然是PCa诊断的标准。目前的研究正在调查现代成像技术是否可以识别肿瘤的部位。有两个主流显示出有希望的初步结果：磁共振成像（MRI）和弹性成像技术。MRI显示出有希望的结果，特别是在使用多参数方法（mpMRI）时，但其高成本和有限的可用性阻碍了其更广泛的使用，特别是在世界上资源贫乏的地区。前列腺弹性成像是一种新兴的成像方式，其包括对前列腺硬度的评估。与伤口修复的细胞过程类似，通常认为正常组织基质响应于努力修复由于癌细胞侵袭引起的损伤。已得出结论，基质反应的特征还在于胶原沉积增加。由于增加胶原沉积导致肿瘤硬度增加，这表明定量硬度估计可能被证明是评估PCa等级和识别更具侵袭性癌症的有效生物标志物。根治性手术和全腺体治疗对于治疗局限性前列腺癌仍然存在争议，因为可能存在泌尿生殖系统和直肠侧-作为损害邻近组织的结果的影响。诸如高强度聚焦超声（HIFU）、血管靶向光动力学疗法、放射性消融和冷冻疗法的聚焦疗法正在成为用于治疗前列腺中的局部单灶性和多灶性癌症病变同时减少副作用的合适方法。然而，它们的成功应用将大大受益于术中监测系统。尽管前景光明，但最终目标通常仍然是腺体的全部或一半体积，这主要是由于肿瘤和治疗区域的确切位置和轮廓的不确定性。在这种局部消融治疗中，组织硬度由于凝固性坏死而急剧增加。这鼓励进一步调查的弹性成像作为一种方法，用于监测热消融在prostate.本研究的目的是开发一个系统，并证明使用经尿道剪切波弹性成像（TU-SWE）方法的可行性，用于诊断和消融监测PCa。申请人已经使用新型一次性探头的缩放版本和图像重建软件证明了该方法的概念验证。下一阶段的工作将是生产TU-SWE医疗原型探头，其电子控制系统遵循为概念验证实验室原型建立的相同制造工艺。图像重建软件的改进将包括将波传播模型扩展到现实的3D几何形状，并使用机器学习来提高并行临床研究数据的图像分辨率。因此，这种诊断和治疗监测工具将导致前列腺癌的早期检测和更有效，因此具有成本效益的癌症治疗，节省NHS的时间，资源和金钱。

Prostate Cancer (PCa) is the most common cancer in men in the UK. It is also the second cause of cancer death after lung cancer. It represents around 13% of all cases of cancer and accounts for 7% of all UK cancer deaths. The incidence of PCa increases with age, affecting mainly men over 50 years of age. Prostate carcinoma is often suspected when the serum Prostate-Specific Antigen (PSA) is elevated or an abnormal digital rectal examination is noted. However, PSA screening leads to a substantial number of unnecessary biopsies in patients with no or indolent cancer, who do not need immediate treatment. Despite the low specificity of PSA testing and the uncertainty after negative systematic biopsies, these techniques remain the standard for PCa diagnosis.Current research is investigating whether modern imaging techniques can identify the site of the tumour. There are two main streams that are showing promising preliminary results: Magnetic Resonance Imaging (MRI) and Elastography techniques. MRI is showing promising results, particularly when using a multi-parametric approach (mpMRI), but its high cost and limited availability hold back its wider use, particularly in resource-poor parts of the world. Prostate Elastography is an emerging imaging modality, which consists of the evaluation of prostate stiffness. Analogous to the cellular processes of wound repair, it is generally believed that normal tissue stroma responds in an effort to repair damage due to carcinoma cell invasion. It has been concluded that the stromal reaction is also characterized by elevated collagen deposition. Since increasing collagen deposition leads to an increase in the tumour rigidity, this suggests that quantitative stiffness estimations may prove to be an effective biomarker for assessing PCa grade and identification of more aggressive cancers.With regards to treatment options, radical surgery and whole-gland therapies remain controversial for treatment of localised prostate cancer due to the possibility of genitourinary and rectal side-effects as a consequence of damaging contiguous tissues. Focal therapies, such as High Intensity Focused Ultrasound (HIFU), Vascular Targeted Photodynamic Therapy, Radiofrequency Ablation and Cryotherapy are emerging as suitable methods for treating localised unifocal and multifocal cancer lesions in the prostate while reducing side-effects. However, their successful application would be benefited greatly by an intraoperative monitoring system. Despite the promising future, the final target is still usually the whole or half volume of the gland, mainly due to the uncertainty of the exact location and contour of the tumour and the treated area. In such focal ablation therapies, tissue stiffness undergoes a dramatic increase due to coagulative necrosis. This encourages further investigation of elastography as a method for monitoring thermal ablation in the prostate.The aim of this study is to develop a system and prove the feasibility of using a Transurethral-Shear Wave Elastography (TU-SWE) approach for diagnosis and ablation monitoring of PCa. The applicants have demonstrated the proof-of-concept for the method using a scaled version of a novel disposable probe and the image reconstruction software. The next stage of the work will see the production of a TU-SWE medical prototype probe with its electronic control system following the same fabrication processes established for the proof-of-concept laboratory prototype. Improvement of the software for image reconstruction will include extending the model of wave propagation to a realistic 3D geometry and using machine learning to enhance the image resolution with data from a parallel clinical study. This diagnostic and treatment monitoring tool will thus lead to earlier detection of prostate cancers and more efficacious and therefore cost-effective cancer treatments, saving the NHS time, resources and money.