Interstitial diffuse optical probe with spectral fitting to measure dynamic tumor hypoxia

Abstract

Understanding the dynamic nature of tumor hypoxia is vital for cancer therapy. The presence of oxygen within a tumor during radiation therapy increases the likelihood of local control. We used a novel interstitial diffuse optical probe to make real-time measurements of blood volume fraction and hemoglobin oxygen saturation within a tumor at a high temporal resolution. This device was initially characterized and benchmarked using a customized vessel designed to control hemoglobin oxygen saturation and blood volume in a solution of blood with different concentrations of an oxygen scavenger, tetrakis (hydroxymethyl) phosphonium chloride. The optical device was found to consistently monitor the changes in oxygen saturation and these changes correlated to the concentration of the oxygen scavenger added. In near-simultaneous measurements of blood volume and oxygen saturation in tumor-bearing mice, the changes in blood volume fraction and oxygen saturation measured with the interstitial diffuse optical probe were benchmarked against photoacoustic imaging system to track and compare temporal dynamics of oxygen saturation and blood volume in a patient-derived xenograft model of hypopharyngeal carcinoma. Positive correlations between our device and photoacoustic imaging in measuring blood volume and oxygen saturation were observed.

Recent Advances in Biomedical Photonic Sensors: A Focus on Optical-Fibre-Based Sensing

“…Regarding oxygen measurement with biosensors, another study presented promising results tackling the challenge of nonreversible sensing when using biosensors. A reversible oxidative stress sensor was demonstrated [84] Recently, Fru et al designed a novel interstitial diffuse optical probe to perform near-simultaneous measurement of blood fraction and oxygen saturation in tissue [85]. The optical probe was used to guide the pump light and collect diffuse light from tumourbearing mice.…”

“…The optical probe was used to guide the pump light and collect diffuse light from tumourbearing mice. They follow the Jacques et al method to retrieve the biological composition of the tissue from optical measurements [85,86]. The results obtained were benchmarked with photoacoustic imaging, achieving a positive correlation between blood volume and oxygen saturation.…”