Targeted magnetic resonance imaging with intraperitoneal and intravenous streptavidin (SA)-DTPA-Gd: a comparative study in tumor-bearing nude mice.

OBJECTIVE: To investigate the effect of streptavidin (SA)-DTPA-Gd after intraperitoneal and intravenous administration for tumor enhancement in targeted magnetic resonance imaging (MRI). METHODS: Biotinylated monoclonal antibody CL3 (600 microg) was intravenously injected into 12 BALB/c nude mice with subcutaneous inoculation of LoVo cells, followed by administration of 80 microg avidin as the chaser 24 h later and then SA-DTPA-Gd was injected intravenously or intraperitoneally after another 30 min. MRI was performed before and 20, 60 min and 3, 6, 9, 12 h after the injection of the contrast agents, and the MR signal intensity of the tumor and liver was determined. RESULT: The maximum enhancement ratio of the tumor was 70.2% in the intravenous injection group and 46.4% in the intraperitoneal group, showing significant difference between them. The maximal enhancement rate of the liver was 23.7% in the intraperitoneal group and 20.4% in the intravenous group, showing no significant difference. CONCLUSION: MR targeted imaging with biotinylated monoclonal antibody CL3 and SA-DTPA-Gd has specific enhancement effect. Higher blood level of SA-DTPA-Gd in the intravenous group facilitates the tumor enhancement in MRI in subcutaneous tumor model.

[CT findings and risk factor analysis of hepatic injury induced by three-dimensional conformal radiation therapy].

OBJECTIVE: To investigate the CT findings and define the risk factors for early hepatic injury induced by three- dimensional conformal radiation therapy in patients with primary liver cancer. METHOD: This study recruited 52 patients with primary liver cancer undergoing photon beam radiation at a total dose of 35 to 65 Gy (49.88+/-7.23 Gy) completed within 18 to 31 d. CT examinations were performed within 1 to 3 months after the completion of the therapy, and logistic regression was used to analyze the CT features of early hepatic injury, in an attempt to define the correlation of the injury occurrence with such factors as the patients' age, gender, treatment portal numbers, liver cirrhosis, transcatheter arterial embolization (TACE), postoperative recurrence, total radiation dose, target volume and fractional dose. RESULTS: Thirty-one (59.6%) patients showed CT features of hepatic injury, displayed as the area with hypodensity in consistency with the radiation coverage. The risk factors correlated to the injury occurrence included the total dose, target volume and fractional dose, but not the patients'age, gender, treatment portal number, liver cirrhosis, TACE, postoperative recurrence differences and radiation-induced hepatic injury. CONCLUSION: Early radiation-induced hepatic injury is related to fractional dose, total dose and target volume adopted in radiation therapy. Higher fractional dose, total irradiated dose and larger target volume may result in increased risk of injury.