Highly sensitive magneto-motive photoacoustic and ultrasound (PAUS) imaging with cyclic excitations. (19th January 2016)

• Record Type: Journal Article
• Authors: Arnal, B; Wei, C-W; Li, J; Gao, X; O'Donnell, M
• Is Part Of: Journal of optics. Volume 18:Number 2(2016:Feb.)
• Publication Date: 2016-01-19
• Subjects: photoacoustic imaging -- magneto-motiv -- molecular imaging -- speckle tracking -- ultrasound imaging; Optics -- Periodicals; 535.05
• DOI: 10.1088/2040-8978/18/2/024009
• Languages: English
• ISSNs: 2040-8978

Abstract

Abstract: Highly specific molecular imaging with photoacoustics (PA) must suppress background endogenous signals while maintaining signals from target nanoagents. Magneto-motive PA was introduced to perform motion-based background suppression using a low frequency magnetic field. Previous studies show suppression based on displacement magnitude can suffer if significant physiological motion is present. This limitation can be overcome using cyclic magneto-motive PA (cmmPA), where multiple cycles of an ac magnetic field are used and the coherence of detected displacements is the retrieved information. In this paper, we show a method to enhance the magnetic response of an electromagnet specifically for cmmPA. Several magnetic frequencies were tested and a simple model is proposed to describe displacement frequency dependence. By choosing optimal parameters based on this model, we show that the technique can detect a low number of tagged cells using either US-based or PA-based displacement estimation. In addition, robustness to physiological motion is demonstrated in a moving phantom.