National Tsing Hua University, Institute of Photonics Technologies, Hsinchu 30013, Taiwan.
J Biomed Opt. 2013 Jun;18(6):066002. doi: 10.1117/1.JBO.18.6.066002.
Calcifications are one of the most important indicators for early breast cancer detection. We explore the feasibility of deep-penetration photoacoustic (PA) imaging of calcifications based on a medical ultrasound array imaging platform. Intralipid and chicken breast phantoms embedded with different-sized hydroxyapatite (HA) particles, which are the major components of calcifications, were imaged to verify the equipment's capability and penetration depth for the visualization of calcifications. An optimal near-infrared excitation wavelength was selected to maximize PA signals of HAs, resulting in a better HA signal-to-blood ratio. We demonstrated that PA imaging is capable of visualizing 0.5-mm HA particles at a depth of 3 cm in chicken breast phantoms. The noise-equivalent penetration depth of the system for visualizing 0.5-mm HA particles in the human breast was estimated to be about 2.9 to 3.5 cm, which is clinically relevant as calcifications are usually found at a depth of 0.6 to 3.0 cm. Moreover, the feasibility of differentiating HA from blood by the PA spectroscopic technique was presented and the mechanism of the HA signal generation was discussed. The results show that PA imaging is a promising technique for real-time visualization of breast calcifications.
钙化是早期乳腺癌检测的最重要指标之一。我们探索了基于医学超声阵列成像平台的深穿透光声 (PA) 成像对钙化的可行性。内脂乳和鸡胸模拟体中嵌入了不同大小的羟磷灰石 (HA) 颗粒，HA 是钙化的主要成分，这些模拟体用于验证设备对钙化可视化的能力和穿透深度。选择了最佳的近红外激发波长来最大化 HA 的 PA 信号，从而获得更好的 HA 信号与血液的比值。我们证明 PA 成像能够在鸡胸模拟体中可视化深度为 3cm 的 0.5mm HA 颗粒。该系统用于可视化人体乳房中 0.5mmHA 颗粒的噪声等效穿透深度估计约为 2.9 至 3.5cm，这在临床上是相关的，因为钙化通常位于 0.6 至 3.0cm 的深度。此外，还提出了通过 PA 光谱技术区分 HA 和血液的可行性，并讨论了 HA 信号产生的机制。结果表明，PA 成像技术是实时可视化乳房钙化的一种很有前途的技术。
