First experience with a novel luminescence-based optical sensor for measurement of oxygenation in tumors

Abstract

Background. The purpose of this preliminary study was to evaluate a novel luminescence-based fiber-optic sensor (OxyLite system) for the measurement of partial pressure of oxygen (pO2) in tumors and for the detection of changes in pO2 as a function of time. The new method was used simultaneously with the laser Doppler flowmetry method for the measurement of relative tissue perfusion.

Materials and methods. Blood perfusion and pO2 were measured continuously via fiber-optic sensors inserted into SA-1 tumors in anesthetized A/J mice. The changes in blood flow and oxygenation of tumors were induced by transient changes of the parameters of anesthesia and by injection of a vasoactive drug hydralazine.

Results. Both optical methods used in the study successfully detected the induced changes in blood flow and pO2. The measurements of pO2 were well correlated with measurements of microcirculatory blood perfusion. In the majority of pO2 measurements, we observed an unexpected behavior of the signal during the stabilization process immediately after the insertion of the probe into tumor. This behaviour of the pO2 signal was most probably caused by local tissue damage induced by the insertion of the probe.

Conclusion. The novel luminescence-based optical oximetry can reliably detect local pO2 changes in tumors as a function of time but some aspects of prolonged pO2 measurement by this method require further investigation.