Objective  To study the signal enhancement of lung adenocarcinoma nude mice after injection of immunomagnetic beadsolution(magnetic beads conjugated with monoclonal antibody NJ001) in micro-CT scan.

  Methods  The models of lung adenocarcinoma nude mice were established by injecting SPC-A1-luc cells through the tail vein and were validated by bioluminescence imaging(BLI).The nude mice were divided into three groups: physiological saline group, bare magnetic bead group, and immunomagneticbead group.Three groups of nude mice were injected with physiological saline, 750 nm bare magnetic bead solution, and immunomagnetic bead solution via the tail vein every week, and micro-CT scan was taken before and 4 h after injection.Immunohistochemistry(IHC)was used to detect the expression of antigen SP70 in tumor tissues.

  Results  The tumor was detected in the immunomagneticbead group at the fourth week, whereas in the physiological saline and bare magnetic bead groups, the tumor was undetectable untilthe sixth week.The tumor intensities detected at the sixth week by micro-CT scan in the physiological saline, bare magnetic bead, andimmunomagnetic bead groups were 59.05±0.66, 60.69±0.55, and 58.25±0.32 before injection and 60.30±1.83, 61.05±0.68, and67.41±3.82 after injection, respectively.Compared with the tumor intensities before injection, they significantly increased after injection in the immunomagnetic bead group; the difference was statistically significant(P=0.0079).By contrast, no statistical significancewas observed in the tumor intensities before and after injection in the physiological saline and bare magnetic bead groups(P=0.1867and P=0.3839, respectively).

  Conclusion  The immunomagnetic beads had enhanced effect on micro-CT scan of lung adenocarcinomanude mouse models.