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Classification of blood cells and tumor cells using label‐free ultrasound and photoacoustics
Author(s) -
Strohm Eric M.,
Kolios Michael C.
Publication year - 2015
Publication title -
cytometry part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.316
H-Index - 90
eISSN - 1552-4930
pISSN - 1552-4922
DOI - 10.1002/cyto.a.22698
Subject(s) - photoacoustic doppler effect , ultrasound , photoacoustic imaging in biomedicine , photoacoustic effect , signal (programming language) , ultrasonic sensor , materials science , melanoma , absorption (acoustics) , microscope , biomedical engineering , pathology , optics , medicine , physics , computer science , cancer research , radiology , composite material , programming language
A label‐free method that can identify cells in a blood sample using high frequency photoacoustic and ultrasound signals is demonstrated. When the wavelength of the ultrasound or photoacoustic wave is similar to the size of a single cell (frequencies of 100–500 MHz), unique periodic features occur within the ultrasound and photoacoustic power spectrum that depend on the cell size, structure, and morphology. These spectral features can be used to identify different cell types present in blood, such as red blood cells (RBCs), white blood cells (WBCs), and circulating tumor cells. Circulating melanoma cells are ideal for photoacoustic detection due to their endogenous optical absorption properties. Using a 532 nm pulsed laser and a 375 MHz transducer, the ultrasound and photoacoustic signals from RBCs, WBCs, and melanoma cells were individually measured in an acoustic microscope to examine how the signals change between cell types. A photoacoustic and ultrasound signal was detected from RBCs and melanoma cells; only an ultrasound signal was detected from WBCs. The different cell types were distinctly separated using the ultrasound and photoacoustic signal amplitude and power spectral periodicity. The size of each cell was also estimated from the spectral periodicity. For the first time, sound waves generated using pulse‐echo ultrasound and photoacoustics have been used to identify and size single cells, with applications toward counting and identifying cells, including circulating melanoma cells. © 2015 International Society for Advancement of Cytometry