A Biomagnetic Sensor for Detecting Breast Cancer

早期发现乳腺癌是癌症成像的主要目标，在肿瘤生长的早期阶段识别肿瘤以确定其类型是很重要的。标准的x射线乳房x线摄影并不总是提供充分的诊断；例如，在乳房致密或辐射结疤的情况下，通常在发生显著生长之前无法识别肿瘤的存在。为了避免这些问题，人们正在开发其他方法，包括核磁共振成像、超声、闪烁成像和其他方法。本文描述了一种利用生物磁传感器检测靶向肿瘤的超顺磁粒子的新方法。这项技术利用了大量关于使用含铁核的纳米颗粒的研究，这些纳米颗粒涂有各种各样的药物，这些药物可以通过肿瘤密集的血管化或通过特异性抗体来靶向肿瘤。使用超导量子干涉器件（SQUID）的标准生物磁传感器能够检测到这种材料的毫微克级。对这种被称为超小氧化铁颗粒（USPIO）的纳米颗粒使用的研究表明，这种数量的纳米颗粒很容易被注射到肿瘤部位，注射量低于耐受性水平的数量级，并且具有显著的肿瘤与正常组织密度比。本I期研究的具体目的是：(1)构建含有各种类型USPIO剂的小内含物的乳房假体，(2)测量该假体中磁化USPIO内含物的磁场，(3)提供专门用于乳腺癌成像的生物磁性传感器系统的初步设计，以及(4)设计通过抗体结合在肿瘤中或肿瘤血管结构微血管中的超顺磁性纳米颗粒的最佳磁化方法。

Early detection of breast cancer is a primary goal in cancer imaging and it is important to identify tumors at an early stage of growth to identify their type. Standard x-ray mammography does not always provide adequate diagnosis; e.g., in cases such as dense or radiation-scarred breasts, and often does not identify tumor presence until significant growth has occurred. Alternative methods are being developed to circumvent these problems, including MRI, ultrasound, scintigraphy, and other methods. A novel method using biomagnetic sensors to detect superparamagnetic particles targeted to tumors is described here. This technique takes advantage of a large amount of research into the use of nanoparticles containing ferric cores and coated with various agents which target tumors either through their dense vascularization or through specific antibodies. Standard biomagnetic sensors using Superconducting Quantum Interference Devices (SQUID) are capable of detecting nanograms of such materials. Research into the use of such nanoparticles, referred to as ultra-small particles of iron oxide (USPIO) indicate that this quantity is easily deliverable to tumor sites with injections orders-of-magnitude below tolerance levels and with significant tumor-to-normal tissue density ratios. This Phase I study has the specific aims of (1) constructing a breast phantom with small inclusions of USPIO agents of various types, (2) measuring the magnetic fields of magnetized USPIO inclusions in this phantom, (3) provide a preliminary design of a biomagnetic sensor system specifically for breast cancer imaging, and (4) design optimal methods for magnetizing the superparamagnetic nanoparticles whether bound in a tumor by antibodies or in microvessels of tumor vascular structure.