Development platform for acoustoelectric impedance tomography in internal radiation therapy

乳腺癌和前列腺癌分别是加拿大女性和男性最常见的浸润性癌症。目前，每7名加拿大男性中就有1人会在一生中患上前列腺癌，每27人中就有1人死于前列腺癌；每4例诊断中就有1例死亡，与女性乳腺癌的比率相似。宫颈癌是加拿大女性的另一个主要健康问题，2017年诊断出1550例，估计有400人死亡。内放射治疗是治疗这些疾病的一种常见的微创疗法。在这一过程中，长针在超声图像引导下经皮插入肿瘤，永久植入放射性种子，其发射的辐射在几周的过程中治疗癌细胞腐烂。众所周知，超声成像缺乏所需的分辨率来可视化和描绘内放射治疗中的癌症结构和异常。事实上，医生可以瞄准低回声区域，但据报道，这些癌症中高达40%在超声波下是看不见的，这使得肿瘤定位变得极其困难。*我们正在开发一种新的内放射治疗成像方法。在我们的方法中，针上安装了微小的电极，这些电极能够测量组织的电导率，并用于从组织内部创建癌症组织的断层图像，并且其对比度比超声图像高得多。然后将聚焦的超声束施加到组织上，以改变局部电导率，这反过来又改变了断层图像。这允许从通过耦合电阻抗断层扫描和局部声压而丰富的数据中提取关于组织的更多信息。结果是一组内部组织的图像，结合了阻抗断层扫描的对比度和超声图像的分辨率。它有可能成像组织包裹体和病变，否则在传统的超声成像中看不到。更准确的成像将使主要癌症的治疗更有效，并使内部癌症能够被考虑用于其他类型的癌症。*我们研究的连续性需要立即获得一台具有开放架构、任意波形生成和射频(RF)数据采集能力的超声波机，以及一种跟踪组织中手术工具的方法。在这项提案中，要求获得资金以获得升级我们的实验装置所需的开放式结构的研究型超声波机和电磁工具跟踪系统。结合起来，这些设备将形成一个最先进的研究平台，用于开发一种新的癌症诊断和治疗成像方法。**

Breast and prostate cancers are the most common invasive cancers amongst Canadian women and men, respectively. Currently, 1 in 7 Canadian men will develop prostate cancer during their lifetime and 1 in 27 will die from it; a ratio of 1 death per 4 diagnoses, similar to the ratio observed for breast cancer in women. Cervical cancer is another major health problem amongst Canadian women with 1550 cases diagnosed and an estimated 400 deaths in 2017. Internal radiation therapy is a common minimally invasive treatment for these conditions. In this procedure, long needles are inserted percutaneously into the tumour under ultrasound image guidance to permanently implant radioactive seeds whose emitted radiation treats the cancer cells as it decays over the course of several weeks. It is well-recognized that ultrasound imaging lacks the resolution required to visualize and delineate cancerous structures and abnormalities in internal radiation therapy. In fact, physicians can target hypoechoic regions but it has been reported that up to 40% of these cancers are invisible under ultrasound, making tumour targeting extremely difficult. ******We are developing a new imaging method for internal radiation therapy. In our approach, needles are instrumented with tiny electrodes that are able to measure the electric conductivity of the tissue and used to create tomographic images of the cancerous tissue from within it, and that with much higher contrast than that of ultrasound images. Focused ultrasound beams are then applied to the tissue to alter the local electrical conductivity, which in turn changes the tomographic images. This allows extracting more information about the tissue from data that has been enriched by coupling electric impedance tomography and localized acoustic pressure. The result is a set of images of the inner tissue that combines the contrast of impedance tomography and the resolution of ultrasound images. It has the potential to image tissue inclusions and lesions that are otherwise not visible in traditional ultrasound imaging. More accurate imaging will make treatment for leading forms of cancer more efficient and enable internal to be considered for other types of cancers. ******The continuity of our research requires immediate access to an ultrasound machine with an open architecture, arbitrary waveform generation, and radio frequency (RF) data acquisition capabilities, and a means of tracking surgical tools in tissue. In this proposal, funding is requested to acquire a research ultrasound machine with an open architecture and an electromagnetic tool tracking system that are needed to upgrade our experimental setup. Combined, the equipment will form a state of the art research platform for the development of a new imaging method for cancer diagnosis and treatment. **