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No sponsorships or competing interests have been disclosed for this article. Objective. The aim of this study was to investigate how head and neck squamous cell carcinoma (HNSCC) tissue biopsies maintained in a pseudo in vivo environment within a bespoke microfluidic device respond to radiation treatment. Study Design. Feasibility study. Setting. Tertiary referral center. Subjects and Methods. Thirty-five patients with HNSCC were recruited, and liver tissue from 5 Wistar rats was obtained. A microfluidic device was used to maintain the tissue biopsy samples in a viable state. Rat liver was used to optimize the methodology. HNSCC was obtained from patients with T1-T3 laryngeal or oropharyngeal SCC; N1-N2 metastatic cer-vical lymph nodes were also obtained. Irradiation consisted of single doses of between 2 Gy and 40 Gy and a fractio-nated course of 532 Gy. Cell death was assessed in the tissue effluent using the soluble markers lactate dehydrogen-ase (LDH) and cytochrome c and in the tissue by immuno-histochemical detection of cleaved cytokeratin18 (M30 antibody). Results. A significant surge in LDH release was demon-strated in the rat liver after a single dose of 20 Gy; in HNSCC, it was seen after 40 Gy compared with the con-trol. There was no significant difference in cytochrome c release after 5 Gy or 10 Gy. M30 demonstrated a dose-dependent increase in apoptotic index for a given increase in single-dose radiotherapy. There was a significant increase in apoptotic index between 132 Gy and 532 Gy. Conclusion. M30 is a superior method compared with soluble markers in detecting low-dose radiation-induced cell death. This microfluidic technique can be used to assess radiation-induced cell death in HNSCC and therefore has the poten-tial to be used to predict radiation response