Photodynamic Therapy Applications in Oncological Imaging

Photodynamic therapy (PDT) has emerged as a versatile modality in cancer management, combining selective tumour ablation with real-time optical monitoring. Central to this approach is the administration of a photosensitiser that preferentially accumulates in malignant tissue, followed by irradiation with light of an appropriate wavelength. Upon activation, the photosensitiser generates reactive oxygen species that induce direct cytotoxicity, vascular shutdown and immunogenic cell death. Concurrently, a suite of imaging techniques—including fluorescence intensity mapping, fluorescence lifetime imaging, optical coherence tomography (OCT) and optical coherence angiography (OCA)—enables non-invasive assessment of photosensitiser distribution, vascular integrity, tissue oxygenation and metabolic shifts. These modalities guide treatment delivery, delineate tumour margins, predict therapeutic response and monitor post-treatment evolution. Integration of functional and structural imaging in PDT thus offers a powerful framework for personalised oncology, reducing collateral tissue damage and improving clinical outcomes.

Research from Nature Portfolio

Recent studies have advanced the use of optical coherence angiography as a label-free, high-contrast method for visualising microvascular networks during and after PDT. In preclinical murine models, OCA detected early vascular occlusion and haemodynamic changes within 24 hours of treatment, with metrics such as perfused vessel density correlating strongly with long-term tumour regression or regrowth. A complementary investigation applied OCA in patients with basal cell carcinoma, demonstrating that pre-treatment vascular patterns predict lesion subtype and guide biopsy, while 24-hour post-PDT vascular metrics achieve over 95% accuracy in forecasting clinical outcome. Furthermore, refined analyses of peri-tumour microvasculature have identified early biomarkers of therapeutic success, enabling rapid adaptation of light dosimetry and photosensitiser dosing to maximise efficacy.

Photodynamic Therapy Applications in Oncological Imaging publication trend

The graph below shows the total number of articles in photodynamic therapy applications in oncological imaging across all publications each year (not limited to Nature Index journals).

Technical terms

Photosensitiser: A light-activated compound that accumulates preferentially in tumour tissue and, upon irradiation, produces reactive oxygen species to induce cell death.

Fluorescence lifetime imaging: A technique that measures the decay time of a fluorophore’s excited state to probe local biochemical environments and metabolic states.

Optical coherence angiography (OCA): A label-free imaging modality derived from OCT that visualises blood flow and microvascular networks in three dimensions.

Photobleaching: The irreversible loss of photosensitiser fluorescence during light exposure, used as a surrogate marker for reactive oxygen species generation and treatment progress.

Perfused vessel density: A quantitative metric from OCA representing the proportion of active microvasculature within a region of interest, correlated with therapeutic response.

References

1. Effects of Photodynamic Therapy on Tumor Metabolism and Oxygenation Revealed by Fluorescence and Phosphorescence Lifetime Imaging. International Journal of Molecular Sciences (2024).
2. Post-Operational Photodynamic Therapy of the Tumor Bed: Comparative Analysis for Cold Knife and Laser Scalpel Resection. Biomedicines (2024).
3. Phototheranostics of Cervical Neoplasms with Chlorin e6 Photosensitizer. Cancers (2022).
4. Photodynamic therapy monitoring with optical coherence angiography. Scientific Reports (2017).
5. Optical coherence angiography for pre-treatment assessment and treatment monitoring following photodynamic therapy: a basal cell carcinoma patient study. Scientific Reports (2019).
6. Accurate early prediction of tumour response to PDT using optical coherence angiography. Scientific Reports (2019).