Photoacoustic lifetime imaging of dissolved oxygen using methylene blue
Photoacoustic lifetime imaging of dissolved oxygen using methylene blue
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DOI：
10.1117/1.3465548
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发表时间：
2010-07-01
影响因子：
3.5
通讯作者：
Ashkenazi, Shai
中科院分区：
文献类型：
--
作者：
Ashkenazi, Shai
测量生物组织中溶解氧的分布对于癌症诊断、预后和治疗优化至关重要。肿瘤缺氧提示预后不良和对放疗的抵抗力。尽管其具有重要的临床意义，但当前的成像方式还没有提供组织氧的直接成像。我们提出的初步结果证明了光声寿命成像 (PALI) 在组织氧无创 3D 成像方面的潜力。该技术基于亚甲基蓝 (MB) 染料激发态寿命的光声探测。 MB 是 FDA 批准的水溶性染料，峰值吸收位于 660 nm。双脉冲激光系统（泵浦探针）用于激发染料并通过检测光声发射来探测其瞬态吸收。 MB 的弛豫速率与氧浓度线性相关。我们的测量显示在 810 nm 探测波长下具有高光声信号对比度，其中激发态吸收比基态吸收高四倍以上。演示了简单模型的成像。最后，我们讨论了该技术在临床环境中的可能实施，并将其与光动力疗法 (PDT) 相结合以进行实时治疗监测。 (C) 2010 年光电仪器工程师协会。 [DOI：10.1117/1.3465548]
Measuring distribution of dissolved oxygen in biological tissue is of prime interest for cancer diagnosis, prognosis, and therapy optimization. Tumor hypoxia indicates poor prognosis and resistance to radiotherapy. Despite its major clinical significance, no current imaging modality provides direct imaging of tissue oxygen. We present preliminary results demonstrating the potential of photoacoustic lifetime imaging (PALI) for noninvasive, 3-D imaging of tissue oxygen. The technique is based on photoacoustic probing of the excited state lifetime of methylene blue (MB) dye. MB is an FDA-approved water soluble dye with a peak absorption at 660 nm. A double pulse laser system (pump probe) is used to excite the dye and probe its transient absorption by detecting photoacoustic emission. The relaxation rate of MB depends linearly on oxygen concentration. Our measurements show high photoacoustic signal contrast at a probe wavelength of 810 nm, where the excited state absorption is more than four times higher than the ground state absorption. Imaging of a simple phantom is demonstrated. We conclude by discussing possible implementations of the technique in clinical settings and combining it with photodynamic therapy (PDT) for real-time therapy monitoring. (C) 2010 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3465548]