It is established that tumour hypoxia is a predictor of cancer disease progression, treatment failures, and metastatic potential. There remains a need for oxygen delivery mechanisms for hypoxia reduction. The ideal method for measuring oxygen in tissue is noninvasive and quantitative, allowing tumour pO2 measurements to be obtained before, during, and after treatment. We investigated effects of oxygen nano-carriers on the longitudinal relaxation times of tumour tissues in vivo and a phantom. T1 decreased with increased oxygen concentration in phantom. The injection of the oxygenated nanobubbles resulted in a statistically significant decrease in T1-weighted signal when measured 6-8 minutes post-injection.