Abstract: Objective   To explore the effect of 6-MeV X-ray radiotherapy on secondary Echinococcus multilocularis infection in rats.   Methods   Female SD rats were used to develop a secondary infection model, and then randomly divided into experimental group and control group （5/group）. Rats in experimental group received two irradiations at 7-day intervals with the same dose （20 Gy） which applied with 6-MeV ray. The rats in control group did not receive any treatment. At one month after the second irradiation, the pathomorphological changes of E. multilocularis cysts were observed.  Results   Cysts in experimental group showed different degrees of damage, including that the laminated layer and germinal layer became swollen and separated from each other, brood capsules and protoscoleces were rare. The structure of cysts was normal in control group, laminated layer and germinal layer were clear, and there were many protoscoleces in the brood capsule.  Conclusion   6 MeV radiotherapy can inhibit the growth of E. multilocularis.

Key words: Alveococcosis, Echinococcus multilocularis, Radiotherapy, Rat