Microendoscopy for hypericin fluorescence tumor diagnosis in a subcutaneous glioma mouse model
Susan Noell1, Guenther C Feigl, Dzenan Serifi
1Department of Neurosurgery, University of Tübingen, Hoppe-Seyler-Str. 3, 72076 Tübingen, Germany.
Background:
New treatment strategies for malignant gliomas are indispensible, due to the poor prognosis for patients. Fluorescence diagnosis (FD) and photodynamic therapy (PDT) are currently under intensive investigation and seem to improve the prognosis. Especially for deep seated malignant brain lesions and in order to optimize therapy new diagnostic tools are needed.
Methods:
In a syngeneic subcutaneous glioma mouse model we investigated the time dependent hypericin (HYP) uptake in malignant tumor tissue by microendoscopically fluorescence measurements. The HYP fluorescence in tumor was also detected by fluorescence microscopy (FM) and was compared to endoscopic data.
Results:
Both methods, microendoscopy and FM, demonstrated time dependent HYP uptake in subcutaneously implanted mouse glioma. Maximum of HYP uptake was achieved after 6h, measured with both methods. FM reached a 10-fold increase in fluorescence intensity compared to the autofluorescence. Measured by microendoscopy a 2.2-fold HYP fluorescence intensity compared to the autofluorescence was detected. Microendoscopy enables visualization of small vessels even in healthy brain tissue by intravascular HYP fluorescence.
Conclusion:
The new developed microendoscope enables not only fluorescence based discrimination of tumor and healthy tissue, but also semiquantitative measurements of fluorescence intensities in vivo. Individual repetitive fluorescence diagnosis will become possible by this method and opens up new possibilities for determining optimal settings of light applications for PDT.
Insights
A novel microendoscope allows for fluorescence-guided diagnosis and semiquantitative measurements of hypericin uptake in malignant gliomas. This tool aids in optimizing photodynamic therapy for brain tumors.
Area of Science:
- Oncology
- Medical Imaging
- Biomedical Engineering
Background:
- Malignant gliomas have a poor prognosis, necessitating novel therapeutic strategies.
- Fluorescence diagnosis (FD) and photodynamic therapy (PDT) show promise for improving patient outcomes.
- Advanced diagnostic tools are crucial for deep-seated brain lesions and therapy optimization.
Purpose of the Study:
- To investigate time-dependent hypericin (HYP) uptake in malignant glioma tissue using microendoscopic fluorescence measurements.
- To compare microendoscopic data with fluorescence microscopy (FM) for HYP detection.
- To evaluate the potential of a new microendoscope for in vivo diagnostics.
Main Methods:
- Utilized a syngeneic subcutaneous glioma mouse model.
- Measured time-dependent HYP uptake via microendoscopic fluorescence.
- Compared microendoscopic findings with FM detection of HYP fluorescence.
Main Results:
- Both microendoscopy and FM confirmed time-dependent HYP uptake in gliomas, peaking at 6 hours.
- FM showed a 10-fold increase in fluorescence intensity versus autofluorescence.
- Microendoscopy detected a 2.2-fold increase and visualized small vessels via intravascular HYP fluorescence.
Conclusions:
- The developed microendoscope enables in vivo, fluorescence-based discrimination of tumor and healthy tissue.
- It allows for semiquantitative fluorescence intensity measurements, facilitating repetitive FD.
- This technology offers new possibilities for optimizing light application settings in PDT.
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