三种蔬菜对土壤中Sr元素富集和转移特性的研究

目的 探索放射性核素⁹⁰Sr在土壤-植物系统中的转移特性,并初步分析植物不同组织对土壤中不同浓度Sr的吸收积累特征.方法 利用稳定性核素⁸⁸Sr替代放射性核素⁹⁰Sr进行室内盆栽种植小白菜、芹菜和萝卜的实验.采用电感耦合等离子体发射光谱法(ICP-AES)测定上述3种蔬菜和土壤中Sr的浓度,并计算上述3种蔬菜根部及茎叶部对Sr的转运系数(TF)及富集率(CR),进而研究Sr在土壤-植物系统中的转移特征.结果 土壤中Sr浓度对于蔬菜的不同组织具有显著影响(F=5.90~139.39,P<0.05).在398.33、477.99和557.57 mg/kg的土壤Sr浓度条件下,小白菜、芹菜和萝卜不同组织Sr浓度均高于对照组(t=-10.49~7.41,P<0.05).除了芹菜茎部之外,3种蔬菜的其他组织与实验土壤中Sr含量呈正相关关系(r=0.88~0.99,t=7.41~15.96,P<0.05).小白菜和萝卜各组织样本的转运系数(基于干重)>1,且小白菜和萝卜中的富集率表现为:茎叶部>根部(F=8.22、91.49,P<0.05).结论 3种蔬菜对Sr均有一定的富集作用.     

Assessment of three different software systems in the evaluation of dynamic MRI of the breast

Objective

The aim was to compare the diagnostic performance and handling of dynamic contrast-enhanced MRI of the breast with two commercial software solutions (“CADstream” and “3TP”) and one self-developed software system (“Mammatool”).

Materials and methods

Identical data sets of dynamic breast MRI from 21 patients were evaluated retrospectively with all three software systems. The exams were classified according to the BI-RADS^® classification. The number of lesions in the parametric mapping was compared to histology or follow-up of more than 2 years. In addition, 25 quality criteria were judged by 3 independent investigators with a score from 0 to 5. Statistical analysis was performed to document the quality ranking of the different software systems.

Results

There were 9 invasive carcinomas, one pure DCIS, one papilloma, one radial scar, three histologically proven changes due to mastopathy, one adenosis and two fibroadenomas. Additionally two patients with enhancing parenchyma followed with MRI for more than 3 years and one scar after breast conserving therapy were included. All malignant lesions were classified as BI-RADS^® 4 or 5 using all software systems and showed significant enhancement in the parametric mapping. “CADstream” showed the best score on subjective quality criteria. “3TP” showed the lowest number of false-positive results. “Mammatool” produced the lowest number of benign tissues indicated with parametric overlay.

Conclusion

All three software programs tested were adequate for sensitive and efficient assessment of dynamic MRI of the breast. Improvements in specificity may be achievable.