Institute for Biological and Medical Imaging (IBMI), Technische Universität München and Helmholtz Zentrum München, Ingolstaedter Landstrasse 1, D-85764 Neuherberg, Germany.
Phys Med Biol. 2011 Jun 7;56(11):3433-44. doi: 10.1088/0031-9155/56/11/016. Epub 2011 May 16.
Near-field radiofrequency thermoacoustic (NRT) tomography is a new imaging method that was developed to mitigate limitations of conventional thermoacoustic imaging approaches, related to hard compromises between signal strength and spatial resolution. By utilizing ultrahigh-energy electromagnetic impulses at ∼20 ns duration along with improved energy absorption coupling in the near-field, this method can deliver high-resolution images without compromising signal to noise ratio. NRT is a promising modality, offering cost-effectiveness and ease of implementation and it can be conveniently scaled to image small animals and humans. However, several of the performance metrics of the method are not yet documented. In this paper, we characterize the expected imaging performance via numerical simulations based on a finite-integration time-domain (FITD) technique and experiments using tissue mimicking phantoms and different biological samples. Furthermore, we show for the first time whole-body tomographic imaging results from mice, revealing clear anatomical details along with highly dissipative inclusions introduced for control. The best spatial resolution achieved for those experiments was 150 µm.
近场射频热声（NRT）层析成像技术是一种新的成像方法，旨在缓解传统热声成像方法的局限性，这些方法在信号强度和空间分辨率之间存在难以调和的折衷。通过利用持续时间约为 20 ns 的超高能电磁脉冲以及近场中改进的能量吸收耦合，该方法可以在不牺牲信噪比的情况下提供高分辨率图像。NRT 是一种很有前途的成像模式，具有成本效益和易于实现的特点，并且可以方便地扩展用于小动物和人类成像。然而，该方法的一些性能指标尚未记录在案。在本文中，我们通过基于有限时域积分（FITD）技术的数值模拟和使用组织模拟体模和不同生物样本的实验来表征预期的成像性能。此外，我们首次展示了来自小鼠的全身层析成像结果，清晰地显示了解剖细节以及为控制而引入的高耗散内含物。在这些实验中实现的最佳空间分辨率为 150 µm。
