QUANTITATIVE FILM AUTORADIOGRAPHY FOR TRITIUM - METHODOLOGICAL CONSIDERATIONS
QUANTITATIVE FILM AUTORADIOGRAPHY FOR TRITIUM - METHODOLOGICAL CONSIDERATIONS
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DOI：
10.1016/0006-8993(85)91613-0
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发表时间：
1985-01-01
期刊：
影响因子：
2.9
通讯作者：
WOOTEN, GF
中科院分区：
文献类型：
--
作者：
GEARY, WA;TOGA, AW;WOOTEN, GF
本文从三个方面研究了用氚塑料标准物进行氚定量胶片放射自显影的细节：（1）氚组织当量（TE）校准;（2）灰和白色物质自吸收差异的校正;（3）使用碳-14标准源作为定量氚组织图像的方法。3 H-组织源和3 H-塑料源均产生3 H-浓度（nCi/mg源重量）与源光密度（OD）的线性对数-对数关系，OD范围可重复（0.080-0.800）。3 H-组织和3 H-塑料的曲线是平行的;对于线性范围内的OD值，未校准的3 H-塑料标准品的自吸收比3 H-组织源高4倍。使用氯仿提取的大鼠脑处理与[14 H]脱氧葡萄糖（[14 C]DG）或[3 H]脱氧葡萄糖（[3 H]DG），我们发现既没有同位素损失，也没有再分布后脱脂（30%的组织干重减少）。氯仿萃取后，含有碳-14的灰色和白色物质结构的OD值不变。灰质OD值增加28.7 ± 5.6%（平均值±S.D.）。含氚的白色物质结构经氯仿萃取后OD值增加115.9 ± 29.3%。当来自未提取组织的任何给定氚OD值在0.080-0.800 OD单位的线性范围内时，氯仿提取后OD的增加是固定百分比。使用可变灰色/白色混合物的氚浸渍牛脑糊剂证实了氚的较高白色物质自吸收的幅度。氯仿提取的组织从[3 H]DG治疗的大鼠，因此是一个合适的程序，直接纠正区域异质性的氚自吸收。最后比较了氚源和碳-14源的成像速率。随着暴露时间的增加，OD的增加率被发现是相等的3 H-组织和3 H-塑料图像;然而，与氚源相比，塑料中的碳-14源显示出更快的图像生成速率（即3 H-和14 C-图像不随暴露时间变化）。非协方差对氚TE校准标准品的影响是随着暴露时间的增加，14 C-塑料标准品的OD值被高估（4周图像与1周图像的比较显示误差为35-40%）。因此，使用碳-14源来量化氚生成的图像需要重新校准所有感兴趣的曝光时间的14 C塑料。
The details of quantitative film autoradiography for tritium using tritium plastic standards were examined with respect to 3 issues: (1) tritium tissue equivalent (TE) calibration; (2) correction of autoabsorption differences for gray and white matter; and (3) the use of carbon-14 standard sources as a method for quantifying tritium tissue images. Both3H-tissue and3H-plastic sources produced linear log-log relationships of3H-concentration (nCi/mg source weight) vs source optical density (OD) over a reproducible OD range (0.080–0.800). The curves for both3H-tissue and3H-plastic were parallel; uncalibrated3H-plastic standards exhibited a 4-fold higher autoabsorption over3H-tissue sources for OD values in the linear range. Using chloroform extraction of brains from rats treated with either [14H]deoxyglucose ([14C]DG) or [3H]deoxyglucose ([3H]DG), we found neither isotope loss nor redistribution after defatting (30% reduction of tissue dry weight). After chloroform extraction, the OD values from both gray and white matter structures containing carbon-14 were unaltered. Gray matter OD values increased by28.7 ± 5.6% (mean±S.D.)in structures containing tritium; white matter structures containing tritium exhibited a115.9 ± 29.3%increase in OD after chloroform extraction. The increase in OD after chloroform extraction was a fixed percent for any given tritium OD value from unextracted tissue when the value was within the linear range of 0.080–0.800 OD units. The magnitude of the higher white matter autoabsorption for tritium was confirmed using tritium impregnated cow brain pastes of variable gray/white mixtures. Chloroform extraction of tissue from [3H]DG treated rats was therefore a suitable procedure for direct correction of regionally heterogeneous autoabsorption of tritium. Finally, the rates of image generation for tritium and carbon-14 sources were compared. The rate of increase of OD with increasing exposure time was found to be equal for3H-tissue and3H-plastic images; sources of carbon-14 in plastic, however, exhibited more accelerated rates of image generation when compared to tritium sources (i.e.3H- and14C-images did not covary with exposure time). The effect of non-covariance on tritium TE calibrated standards was the overestimation of OD values for14C-plastic standards with increasing times of exposure (comparison of 4 week images to 1 week images showed errors of 35–40%). Use of carbon-14 sources to quantify tritium-generated images therefore requiredrecalibrationof14C-plastic for all exposure times of interest.