This book examines Dynamic Light Scattering (DLS) and its derivatives Laser Doppler Flowmetry (LDF), Diffusing Wave Spectroscopy (DWS), Laser Speckle Contrast Imaging (LSCI), and Doppler Optical Coherence Tomography (OCT) for characterizing particle motion in turbid mediums like suspensions and solutions. It focuses on non-invasive blood flow imaging in biological tissues, detailing technological advancements, practical applications, and inherent challenges. Essential for professionals in biomedical optics and medical fields, as well as physics and engineering students, the book highlights its use in brain, skin, and micro-circulation studies, providing key insights and practical guidance. Key Features: • Presents a deep dive into DLS and its derivative techniques. • Emphasizes practical applications, including brain blood flow monitoring, skin perfusion measurements, and micro-circulation characterization. • Delivers insights into the challenges and limitations associated with DLS-based blood flow imaging. Anton Sdobnov earned an M.Sc. in physics with honors from Saratov State University, Russia, in 2013, and subsequently worked as an engineer in the university’s Optics and Biophotonics department until 2015. He then joined the University of Oulu, Finland, as a researcher in 2016. Anton received his Ph.D. in physics from Saratov State University in 2021 and a Dr.Sc. in technology from the University of Oulu in 2022. Evgenii Zherebtsov earned his M.Sc. in Biomedical Engineering in 2010 and D.Sc. in Optical Instrument Engineering in 2014 from Orel State University, Russia. He has an internationally recognized track record with 140 peer-reviewed articles, conference proceedings, book chapters, seven patents, and three monographs in optical diagnostics. Alexander Bykov is an Adjunct Professor in Biophotonics and Sensor Technologies at the University of Oulu, Finland, where he leads the Biophotonics Group since 2019. He received his D.Sc. in Technology from the same university in 2010. He has authored over 130 peer-reviewed papers, conference proceedings, and eight book chapters. Igor Meglinski, MSc, PhD, is a Professor of Quantum Biophotonics and Biomedical Engineering at Aston University, UK. He has authored over 450 research papers, several books, and holds numerous patents. He has delivered more than 800 presentations, including over 400 invited lectures at major international conferences. A Chartered Physicist (CPhys) and Engineer (CEng), he is a Senior Member of IEEE, and Fellow of the Institute of Physics, and Royal Microscopical Society (FRMS), SPIE, and OPTICA.