SU-E-J-196: In-Vivo Tumor Blood-Oxygen Content Measurement via Interstitial Optical Transmission Spectroscopy

Area of Science:

• Biomedical Optics
• Cancer Research
• Medical Physics

Background:

• Hypoxia in tumors impacts radiotherapy efficacy.
• Real-time monitoring of tumor oxygenation is crucial for treatment optimization.
• Diffuse optical transmission spectroscopy offers a non-invasive method for tissue analysis.

Purpose of the Study:

• To apply in-vivo diffuse optical transmission spectroscopy for quantifying interstitial tissue oxygen saturation.
• To investigate real-time tumor reoxygenation dynamics in response to radiotherapy.
• To assess the potential of this technique for optimizing hypofractionated radiation therapies.

Main Methods:

• Utilized fiber optics inserted via hypodermic needles into human head-and-neck tumor xenografts in nude mice.
• Employed a spectrometer and light source to measure transmission spectra.
• Quantified oxygen saturation and hemoglobin concentrations at various time points post-irradiation.

Main Results:

• Successfully measured blood volume, deoxyhemoglobin, and oxyhemoglobin concentrations through spectral fitting.
• Explored different interstitial fiber optic probe configurations to enhance signal strength.
• Identified improved optical coupling and increased source intensity as key factors for signal improvement.

Conclusions:

• The technique provides insights into the temporal dynamics of hypoxia and reoxygenation in tumors during radiation therapy.
• This method is particularly valuable for hypofractionated treatments, enabling optimized timing for increased tumoricidal effects.
• Further development can enhance signal strength for more robust in-vivo measurements.