PCDD/Fs, PBDD/Fs, and PBDEs in the air of an e-waste recycling area (Taizhou) in China: current levels, composition profiles, and potential cancer risks.

Atmospheric concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), and polybrominated diphenyl ethers (PBDEs) were measured in Taizhou, a large electronic equipment waste (e-waste) recycling area in East China. The mean concentrations (in summer and winter) of PCDD/Fs (0.45 and 0.39 pg WHO-TEQ m⁻³, where WHO-TEQ is the toxic equivalent set by the World Health Organisation), PBDD/Fs (0.22 and 0.18 pg WHO-TEQ m⁻³), and PBDEs (270 and 225 pg m⁻³) in this region have declined compared with those in 2005, due to regulations on primitive e-waste recycling activities. However, these concentrations remain higher than the historically highest levels in Europe and North America. The congener profiles of 2,3,7,8-substituted PCDD/Fs were similar, with OCDD, 1,2,3,4,6,7,8-HpCDF, OCDF, and 1,2,3,4,6,7,8-HpCDD being the most abundant congeners at all sites. The PCDD/F homologue profiles in the present study were different from those typically observed at non-e-waste locations, indicating a distinct source in this region. Seasonal differences were found in the lower brominated PBDE profiles. These differences indicate that the PBDE emission sources in summer (e.g., strong evaporation sources) differed from those in winter. However, the relatively steady congener profiles of the highly brominated PBDEs suggest that these PBDEs were controlled primarily by similar emission mechanisms. The lifetime excess cancer risks from exposure to PCDD/Fs and PBDD/Fs via inhalation ranged from 0.7 × 10⁻5 to 5.4 × 10⁻5, or approximately 80 cancer cases in the Taizhou population.

[Magnetic resonance imaging findings of liver injury induced by three-dimensional conformal radiotherapy].

OBJECTIVE: To analyze the magnetic resonance imaging (MRI) findings of radiation-induced liver injury following three-dimensional conformal radiotherapy. METHODS: A retrospective review of the MRI data was conducted in 20 patients treated between September 2000 and October 2005, who suffered liver injuries induced by 1 or 2 three-dimensional conformal radiotherapy sessions for liver neoplasm. The patients underwent MR scans with T2-weighted sequences and T1-weighted sequences in both plain and Gd-DTPA enhanced MRI. Four patients with suspected tumor relapse suggested by MRI were pathologically confirmed to have radiation-induced liver injury. RESULTS: Acute radiation-induced liver injury was represented by large patches of liver edema consistent with the irradiation volume, showing low signal intensity on T1-weighted images (T1WI) and high signal intensity on T2-weighted images (T2WI) without arterial phase enhancement after Gd-DTPA injection. Delayed radiation-induced liver injury was manifested by slightly low-intensity signal on plain T1WI and slightly high-intensity signal on T2WI without obvious arterial phase enhancement following Gd-DTPA injection but with marked enhancement during the portal-venous and delayed phases. CONCLUSION: Radiation-induced liver injury presents characteristic MRI features, and plain and dynamic enhanced MRI can be of great value for its diagnosis.

[Helical CT presentation of focal nodular hyperplasia of the liver].

OBJECTIVE: To improve the diagnostic accuracy of focal nodular hyperplasia (FNH) of the liver by analyzing its findings by helical CT multiphase scanning. METHODS: A retrospective analysis of the plain scanning and dynamic enhanced scanning helical CT findings was conducted in 20 pathologically verified FNH cases. RESULTS: On plain CT scans, the FNH lesions appeared as heterogeneous or homogeneous hypodense areas. In the arterial phase, all lesions were vigorously and homogeneously enhanced except for the central scar and lesions in 1 case. In 6 cases, tortuous and dilated arteries were seen in the center or peripheral of the lesion in 16-slice spiral CT. In the portal venous phase and delayed phase, the lesions were slightly hyperdense, isodense or slightly hypodense. Central scar was found in 13 cases, which showed late enhancement. Atypical findings included multinodular FNH in 2 cases, pseudocapsular enhancement in 2 cases, calcification in 1 case, and necrosis in 1 case. CONCLUSION: Multiphase helical CT scanning can fully display the pathological and blood supply characteristics of FNH and improve the differentiation of FNH from other malignant hypervascular tumors.