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Abstract:
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Tumor oxygenation is a crucial factor to determine the efficiency of non -surgery therapy , such as radiotherapy and chemotherapy . Therefore , various approaches have been applied to tumor in order to improve the tumor oxygen level . Breathing oxygenrich gas with normobaric or hyperbaric pressure has been demonstrated to overcome hypoxia , but with marginal success . Therefore , the outcome would be improved greatly , if the responsive tumors were identified a priori . Two non -invasive techniques were applied to monitor tumor oxygenation dynamics simultaneously when rats were exposed to hyperoxic gas intervention . 19F MRI provides tumor tissue oxygen tension (pO2 ) images , while Near Infrared Spectroscopy (NIRS ) measures global tumor vascular dynamics . Multiple correlations were examined between the rate and vii magnitudes of vascular and tissue oxygen response . In order to extract more physiological information from tumor vascular oxygen measured by NIRS , a mathematical model , modified from Windkessel model , is used to obtain the tumor blood flow and oxygen consumption rate from hemoglobin concentration . Besides normobaric oxygen intervention , hyperbaric oxygen intervention was also adopted to improve tumor oxygenation because it increases oxygen tensions and oxygen delivery to tissue independent of hemoglobin . Two techniques , FOXY fluorescence quenching oxygen sensor and NIRS , were applied simultaneously to monitor tumor tissue and vascular oxygen during and post hyperbaric oxygen administration , so as to investigate tumor oxygenation achieved with hyperbaric oxygen and the preservation of tumor oxygenation after hyperbaric oxygen intervention . I applied combined administration of doxorubicin and hyperbaric oxygen to tumors and compared the tumor oxygenation dynamics , tumor size , body weight and mortality rate between rats with combined therapy and those with doxorubicin alone . Combined application of MRI and NIRS , and FOXY oxygen sensor are novel methodology , which are complementary . Simultaneous application gives us a better understanding on the patho -physiology of tumor and response to therapeutic intervention . |