Circulating tumor cell clusters (CTCCs) are associated with high metastatic potential and poor patient prognosis. However, they are difficult to detect and isolate because of their extremely low numbers. Here, we report on the use of machine learning and deep learning based analysis to achieve accurate detection of CTCCs in flowing whole blood samples relying on the confocal detection of endogenous light scattering signals. Our custom flow cytometer utilizes laser excitation at 405, 488, and 633 nm and confocal detection of the corresponding light scattering signals as well as fluorescence in the 510-530nm range. Samples consist of whole blood isolated from rats spiked with varying concentrations of CTCCs, flowed through the channels of a microfluidic device. The CTCCs express GFP, so that we can detect the strong GFP signal with the 520 nm detector and use it as the ground truth for assessing the performance of algorithms relying on the endogenous signals of the same peaks detected by the other detectors. We achieve a low false alarm rate of 0.78 events/min, a detection purity of 72%, and a sensitivity of 35.3%.
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