Multispectral photoacoustic laser diode systems have multiple wavelengths available simultaneously. In addition to multispectral imaging, this can be exploited to increase the signal to noise ratio (SNR) by combining these wavelengths to form a combined image, but at the loss of spectral information. Here, a novel signal processing concept is introduced, which optimizes the SNR in the reconstructions of single wavelength data from combined acquisitions while simultaneously permitting to obtain a higher SNR fused image from the same data. The concept is derived for an arbitrary number of wavelengths; it is also applicable at low pulse repetition frequencies. The concept is applied in an experiment using two wavelengths, verifying the theoretical results.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1364/OE.23.001816 | DOI Listing |
Laser Photon Rev
October 2024
Harvard Medical School, Boston, MA 02114, USA; Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Cardiology, Erasmus Medical Center, Rotterdam GD3015, The Netherlands; Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
Photoacoustic microscopy (PAM) is a high-resolution and non-invasive imaging modality that provides optical absorption contrast. By employing dual- or multiple-wavelength excitation, PAM extends its capabilities to offer valuable spectroscopic information. To achieve efficient multispectral PAM imaging, an essential requirement is a light source characterized by a high repetition rate and switching rate, a ≈microjoule pulse energy, and a ≈nanosecond pulse duration.
View Article and Find Full Text PDFTalanta
December 2024
Department of Hepato-Pancreato-Biliary Surgery, The Affiliated Lihuili Hospital of Ningbo University, Ningbo, 315211, China; Health Science Center, Ningbo University, Ningbo, Zhejiang, 315211, China. Electronic address:
The hypoxic environment in tumors is closely linked to tumor structure, function, dissemination, invasion, metastasis, and drug resistance. Nitroreductase (NTR) is often recognized as a biomarker to evaluate the hypoxia degree for tumor cells. Traditional detection methods such as PET, MRI and multispectral photoacoustic tomography have limitations.
View Article and Find Full Text PDFPhotoacoustics
October 2024
School of Biomedical Engineering, Southern Medical University, Guangzhou, China.
Multispectral photoacoustic tomography (PAT) is an imaging modality that utilizes the photoacoustic effect to achieve non-invasive and high-contrast imaging of internal tissues but also molecular functional information derived from multi-spectral measurements. However, the hardware cost and computational demand of a multispectral PAT system consisting of up to thousands of detectors are huge. To address this challenge, we propose an ultra-sparse spiral sampling strategy for multispectral PAT, which we named U3S-PAT.
View Article and Find Full Text PDFJ Microsc
December 2024
Department of Biology, University of Crete, Voutes University Campus, Heraklion, Crete, Greece.
This short review discusses the recent developments in low-cost, high-resolution optoacoustic microscopy systems, integrating laser diodes for signal excitation, which are 20-40 times cheaper than the typically employed Q-switched nanosecond laser sources. The development of laser diode-based microscopes can substantially improve not only cost efficiency, but also multispectral capabilities, robustness, portability and overall imaging performance of the optoacoustic technique. To this end, we demonstrate relevant implementations in both time and frequency domain, highlighting their representative applications in biomedical research such as microvasculature imaging, oxygen saturation assessments, hybrid and multiview microscopy of model organisms and tissues and Doppler flow speed measurements.
View Article and Find Full Text PDFNat Commun
November 2024
DTU Electro, Department of Electrical and Photonics Engineering, Technical University of Denmark, Kongens Lyngby, Denmark.
The synthesis of multiple narrow optical spectral lines, precisely and independently tuned across the near- to mid-infrared region, is a pivotal research area that enables selective and real-time detection of trace gas species within complex gas mixtures. However, existing methods for developing such light sources suffer from limited flexibility and very low pulse energy, particularly in the mid-infrared domain. Here, we introduce a concept that is based on the combination of an appropriate design of near-infrared fiber laser pump and cascaded configuration of gas-filled anti-resonant hollow-core fiber technology.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!