Autofluorescence lifetime measurement on oral carcinogenesis

Area of Science:

• Biomedical Optics
• Cancer Diagnostics
• Photodynamic Therapy

Background:

• Autofluorescence lifetime differs between normal and cancerous tissues due to biophysical and biochemical variations.
• Protoporphyrin IX (PplX), a key fluorophore, accumulates in cancerous cells, influencing autofluorescence.
• PplX's emission peak at 630nm under 410nm excitation is sensitive to cellular accumulation.

Purpose of the Study:

• To investigate significant differences in autofluorescence lifetime at 630nm (410nm excitation) between normal and cancerous tissues in vivo.
• To establish autofluorescence lifetime as a potential biomarker for cancer detection and grading.
• To explore the correlation between autofluorescence lifetime and treatment response.

Main Methods:

• In vivo measurement of autofluorescence lifetime at 630nm emission under 410nm excitation.
• Comparison of lifetime values between normal and cancerous tissue samples.
• Analysis of lifetime changes in relation to the degree of carcinogenesis and treatment progression.

Main Results:

• Normal tissues generally exhibit shorter autofluorescence lifetimes (2.8–3.5 ns) compared to abnormal tissues.
• Cancerous tissues show significantly longer autofluorescence lifetimes, averaging around 10 ns.
• Autofluorescence lifetime increases with the degree of carcinogenesis, suggesting a diagnostic indicator.

Conclusions:

• Autofluorescence lifetime measurement at 630nm provides a distinct signature for differentiating normal from cancerous tissues.
• The observed increase in lifetime with carcinogenesis degree offers a quantitative method for cancer assessment.
• Time-series analysis of autofluorescence lifetime decline can potentially monitor treatment efficiency in photodynamic therapy.