RESUMO
Lichens are good biomonitors for air pollution because of their high enrichment capability of atmospheric chemical elements. To monitor atmospheric element deposition using lichens, it is important to obtain information on the multi-element concentrations in lichen thalli. Because of serious air pollution, elemental concentrations in thalli of lichens from North China (especially Inner Mongolia, Hebei, Shanxi and Henan province) are often higher than those from other regions, therefore highlighting the necessity to optimize ICP-AES/MS (Inductively coupled plasma-atomic emission spectroscopy/mass spectrometry) for analyzing lichen element content. Based on the high elemental concentrations in the lichen samples, and the differences in the sensitivity and detection limits between ICP-MS and ICP-AES, we propose a protocol for analyzing 31 elements in lichens using ICP-AES/MS. Twenty-two elements (Cd, Ce, Co, Cr, Cs, Cu, K, La, Mo, Na, Ni, Pb, Rb, Sb, Sc, Sm, Sr, Tb, Th, Tl, V and Zn) can be identified by using microwave digestion- ICP-MS, and 9 elements (Al, Ba, Ca, Fe, Mg, Mn, P, S and Ti) by using ashing-alkali fusion digestion- ICP-AES.
RESUMO
OBJECTIVE: To evaluate the clinical value of (99)Tc(m)-sandostatin receptors imaging ((99)Tc(m)-sandostatin) in detection of lung tumors in comparison with fludeoxyglucose F18 dual head coincidence imaging ((18)F-FDG DHC). METHODS: Fifty-six consecutive patients (40 men, 16 women; mean age: 62 years, range 35 - 80 years) with pulmonary neoplasm were referred for evaluation. All underwent sandostatin scintigraphy using hybrid SPECT/CT. (18)F-FDG DHC imaging was also performed in 23 patients using the same camera. The tumor uptake of (99)Tc(m)-sandostatin and (18)F-FDG DHC were measured respectively and expressed as the ratio of T/Nr and T/Nm. Final clinical diagnosis was confirmed by histopathological study. RESULTS: Out of 56 cases, 46 were confirmed to be malignant and 10 benign. The sensitivity, specificity and accuracy of (99)Tc(m)-sandostatin in diagnosis of lung cancer were 95.7%, 90.0%, 94.6%, respectively. The positive predictive value (PPR) was 97.8%, and the negative predictive value (NPR) was 81.8%. In the 23 patients underwent both methods, the sensitivity, specificity and accuracy of (18)F-FDG DHC were 100%, 60.0%, 82.6%, respectively; the PPR was 76.5%, and the NPR 100%. Out of 13 patients with malignant neoplasms, 6 patients had regional lymph node metastasis, and all of 10 abnormal lymph nodules showed high uptake of FDG, while (99)Tc(m)-sandostatin imaging only 2 regional metastasized lymph nodes in one patient. T/N(r) and T/N(m) were 3.15 +/- 1.30, and 10.61 +/- 4.35 respectively. There was no relationship between sandostatin uptake and glucose metabolism. CONCLUSION: (99)Tc(m)-sandostatin scintigraphy is a promising noninvasive imaging technique for detection of the primary tumor of lung cancer but of limited value in the detection of lymph node metastasis.
