STUDY ON THE NON-INVASIVE MEASUREMENT OF OXYGEN CONCENTRATION IN TUMORS BY NEAR-INFRARED LIGHT AND EVALUATION OF ITS OPTICAL CT IMAGING

目的：开展不同呼吸条件下肿瘤血红蛋白（hb）氧图谱的研究。本研究的目的是进一步发展利用三波长近红外光在小鼠肿瘤中获得可靠的氧-脱氧- hb或总hb和hb o_2饱和度图谱。M&m：采用770nm、808nm和854nm三种半导体脉冲激光器作为近红外光源。脉冲激光束通过放置在肿瘤表面的光纤引导进入肿瘤。通过与光源相对放置的12根光纤中的7根检测穿过肿瘤的光，并将其引导到条纹相机中，同时获得7个时间分辨光谱数据，每个波长使用12 × 7个投影数据，通过滤波后的反投影ct图像重建方法获得氧和脱氧hb分布图像。计算小鼠肿瘤体内总hb和hb o_2饱和度图像。结果：利用近红外光可获得三种呼吸状态下小鼠体内hb o_2饱和度图像。吸碳使肿瘤hb o_2饱和度升高，无呼吸使肿瘤hb o_2饱和度降低。图像显示了吸碳对肿瘤总血红蛋白及其o_2饱和度分布的影响。吸碳后肿瘤血红蛋白体积及血红蛋白饱和度随肿瘤体积的变化。碳吸入增加血红蛋白体积对小肿瘤有效。随着肿瘤体积的增大，肿瘤的hb - o_2饱和度降低。虽然技术的进一步改进将导致更好的分辨率。我们证明了利用近红外光获得小鼠肿瘤体内hb o_2饱和度图像的可行性。

PURPOSE : WE STARTED THE STUDY ON THE HEMOGLOBIN (HB) OXYGEN MAPPING IN TUMORS UNDER VARIOUS CONDITIONS IN BREATHING.THE PURPOSE OF THIS STUDY WAS TO GET A FURTHER DEVELOPMENT USING THREE-WAVELENGTH NEARINFRARED LIGHT TO OBTAIN A RELIABLE OXY-AND DEOXY-HB OR TOTAL HB AND HB O_2 SATURATION MAPPING IN MOUSE TUMOR.M&M : THREE KINDS OF SEMICONDUCTOR PULSE LASER,770NM,808NM AND 854NM,WERE USED AS NEAR-INFRARED LIGHT SOURCES.A PULSE LASER BEAM WAS GUIDE INTO THE TUMOR VIA AN OPTICAL FIBER PUTTING IN THE SURFACE OF THE TUMOR.LIGHT TRANSMITTED THROUGH THE TUMOR WAS DETECTED BY 7 OUT OF 12 OPTICAL FIBERS PLACED ON THE OPPOSITE SIDE FROM THE SOURCE AND GUIDED TO A STREAK CAMERA TO OBTAIN 7 TIME-RESOLVED SPECTRAL DATA SIMULTANEOUSLY.12 TIMES 7 PROJECTION DATA FOR EACH WAVELENGTH WERE USED TO OBTAINED AN IMAGE OF OXY-AND DEOXY-HB DISTRIBUTIONS BY USING A FILTERED BACK-PROJECTION CT IMAGE RECONSTRUCTION METHOD.THE IN VIVO TOTAL HB AND HB O_2 SATURATION IMAGES OF MOUSE TUMOR WERE THEN CALCULATED.RESULTS : IN VIVO HB O_2 SATURATION IMAGES OF MOUSE UNDER THREE BREATHING CONDITIONS COULD BE OBTAINED USING NEAR-INFRARED LIGHT.THE HB O_2 SATURATION OF TUMOR INCREASED BY CARBOGEN INHALATION AND DECREASED BY NO-BREATHING.THE IMAGES EXHIBITED THE EFFECT OF CARBOGEN INHALATION ON TOTAL HB AND ITS O_2 SATURATION DISTRIBUTION FOR TUMORS.THE VARIATION OF HB VOLUME AND HB O_2 SATURATION OF TUMOR AFTER CARBOGEN INHALATION AS A FUNCTION OF TUMOR VOLUME.INCREASING HB VOLUME BY CARBOGEN INHALATION WAS EFFECTIVE TO THE SMALL TUMORS.THE HB O_2 SATURATION OF TUMOR DECREASED BY INCREASING OF THE VOLUME OF TUMOR.ALTHOUGH FURTHER IMPROVEMENT IN THE TECHNIQUE SHOULD RESULT IN BETTER RESOLUTION.WE HAVE DEMONSTRATED THE FEASIBILITY OF USING NEAR-INFRARED LIGHT TO OBTAIN IN VIVO HB O_2 SATURATION IMAGES IN MOUSE TUMOR.