Illuminating Biochemical Differences with Spectroscopy
The researchers first employed spontaneous Raman spectroscopy to analyze fresh-frozen cervical tissue samples from 10 patients diagnosed with squamous cell carcinoma. By targeting the high-wavenumber region (1800–3200 cm⁻¹) of the Raman spectrum, they identified biochemical markers such as elevated levels of lipids, fatty acids, and proteins in cancerous tissues.
The most significant spectral difference between cancerous and normal tissues was observed at 2928 cm⁻¹, a region associated with CH₂ symmetric stretching, common in lipid-rich environments. This served as the foundation for targeted imaging using CARS (1).
Visualizing Cancer with CARS Imaging
To overcome limitations of spontaneous Raman spectroscopy—such as low signal intensity and background noise—the team turned to CARS, a nonlinear optical imaging technique that amplifies Raman signals by up to 100,000 times (1–3). Using a Pico-Emerald laser system, the researchers captured high-resolution images of tissue sections at the 2928 cm⁻¹ vibrational frequency (1).
These CARS images revealed a stark contrast: normal cervical squamous cells displayed nearly zero signal intensity, while keratinized and non-keratinized cancerous cells showed strong Raman signals, allowing for naked-eye identification of cancerous lesions (1).
Moreover, the presence of keratin pearls—distinct structural features in keratinized squamous cell carcinoma—emerged as a potential marker to further subclassify cervical cancer types, providing clinicians with more nuanced diagnostic information (1).
AI-Driven Accuracy with ConvNeXt
To automate the diagnostic process, the team trained a ConvNeXt deep convolutional neural network using the acquired CARS images. This advanced artificial intelligence (AI) model, which excels at visual classification tasks, achieved a verification accuracy of 100% and a loss function of just 0.0927.
ConvNeXt eliminates the need for manual feature engineering, learning directly from raw image data to distinguish tissue types with exceptional precision. This represents a major leap forward in AI-powered pathology, particularly in the early and accurate detection of cervical cancer (1).
Clinical Impact and Future Potential
By combining biochemical specificity with visual clarity and machine learning (ML), the research team has demonstrated a highly sensitive, non-invasive, and scalable diagnostic tool for cervical cancer. The integration of spontaneous Raman and CARS spectroscopy with AI-based image classification opens the door for real-time, label-free cancer diagnostics in clinical settings.
Their findings not only reinforce the diagnostic potential of CARS imaging but also highlight the power of AI to streamline and enhance medical diagnostics (1).
References
(1) Liu, C.; Xiu, C.; Zou, Y.; Wu, W.; Huang, Y.; Wan, L.; Xu, S.; Han, B.; Zhang, H. Cervical Cancer Diagnosis Model Using Spontaneous Raman and Coherent Anti-Stokes Raman Spectroscopy with Artificial Intelligence. Spectrochim. Acta, Part A 2025, 327, 125353. DOI: 10.1016/j.saa.2024.125353
(2) Fujita, K. A Further Leap of Biomedical Raman Imaging. Spectroscopy 2020, 35 (7), 10. https://www.spectroscopyonline.com/view/further-leap-biomedical-raman-imaging (accessed 2025-07-08).
(3) Inoue, K.; Okuno, M. Coherent Anti-Stokes Hyper-Raman Spectroscopy. Nat. Commun. 2025, 16, 306. DOI: 10.1038/s41467-024-55507-0