THz imaging is effective in distinguishing between cancerous, healthy, and fatty tissues in breast tumors, but a challenge remains in the contrast between cancerous and fibroglandular (healthy) tissues. This work investigates carbon-based nanoparticles as potential contrast agents for terahertz imaging of breast cancer. Microdiamonds, nanodiamonds, and nanometer-scale onion-like carbon are characterized with terahertz transmission spectroscopy in low-absorption backgrounds of polydimethylsiloxane or polyethylene. The refractive index and absorption coefficients are calculated based on the measured electric fields. Nanodiamonds show little effect on the terahertz signal, microdiamonds express resonance-like, size-dependent absorption peaks, and onion-like carbon provides a uniform increase in the optical properties even at low concentration. Due to its strong interaction with terahertz frequencies and ability to be activated for selective binding to cancer cells, onion-like carbon is implemented into engineered three-dimensional breast tumor models composed of phantom tissue mimicking infiltrating ductal carcinoma surrounded by a phantom mimicking healthy fibroglandular tissue. This model is imaged using the terahertz reflection mode to examine the effectiveness of contrast agents for differentiation between the two tissue types. In both spectroscopy and imaging, a 10% concentration of onion-like carbon shows the strongest impact on the terahertz signal and holds promise as a terahertz contrast agent.

中文翻译：

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微米、纳米金刚石和纳米洋葱作为乳腺癌造影剂的太赫兹光谱和成像的模型研究


太赫兹成像可有效区分乳腺肿瘤中的癌性组织、健康组织和脂肪组织，但癌性组织和纤维腺（健康）组织之间的对比仍然存在挑战。这项工作研究了碳基纳米粒子作为乳腺癌太赫兹成像的潜在造影剂。在聚二甲基硅氧烷或聚乙烯的低吸收背景下，使用太赫兹透射光谱对微米金刚石、纳米金刚石和纳米级洋葱状碳进行表征。根据测量的电场计算折射率和吸收系数。纳米金刚石对太赫兹信号几乎没有影响，微米金刚石表现出类似共振、尺寸依赖性的吸收峰​​，而洋葱状碳即使在低浓度下也能均匀增加光学特性。由于其与太赫兹频率的强烈相互作用以及被激活以选择性结合癌细胞的能力，洋葱状碳被应用到工程三维乳腺肿瘤模型中，该模型由模仿浸润性导管癌的幻影组织组成，周围环绕着模仿健康纤维腺体组织的幻影组织。该模型使用太赫兹反射模式成像，以检查造影剂区分两种组织类型的有效性。在光谱学和成像方面，10% 浓度的洋葱状碳对太赫兹信号的影响最强，有望成为太赫兹造影剂。