Intraoperative label-free tissue pathology with ultraviolet single-pane illumination microscopy

Lung cancer is one of the leading causes of cancer mortality worldwide, with an estimated 2.2 million new cancer cases and 1.8 million deaths in 2020. Adenocarcinoma is the most common type of non-small cell lung cancer (NSCLC), which is usually developed with a mixture of histologic subtypes. Surgery to remove the affected tissue or tumor is the most curative treatment option for the early-stage NSCLC currently. The clinical diagnosis of NSCLC based on pathological analysis of formalin-fixed and paraffin-embedded (FFPE) tissues is laborious and time-consuming, failing to guide surgeons intraoperatively. Although frozen section can serve as a rapid alternative to FFPE histology, it still requires a turnaround time of 20–30 minutes during surgery. Besides, the diagnostic accuracy of the frozen section could be affected due to the tissue freezing artifacts and inadequate sampling of resection margins. Here, we propose a rapid histological imaging method, termed microscopy with ultraviolet single-plane illumination (MUSI), which enables label-free and non-destructive imaging of freshly excised and unprocessed tissues. The MUSI system allows the surgical specimens with large irregular surfaces to be scanned in a label-free manner at a speed of 0.65 mm2/s with a subcellular resolution, showing great potential as an assistive imaging platform that can provide immediate feedback to surgeons and pathologists for intraoperative decision-making. We demonstrate that MUSI can differentiate between different subtypes of human lung adenocarcinomas, revealing diagnostically important features that are comparable to the gold standard FFPE histology, holding great promise to revolutionize the current practice of surgical pathology.