Research on inter-fraction and intra-fraction motion of crystalline lens in radiotherapy / 解放军医学杂志

ABSTRACT

Objective To investigate the range of inter-fraction and intra-fraction motion of crystalline lens in radiotherapy. Methods The CT and MRI images of 17 patients were registered, and the profile of crystalline lens was delineated to determine the respective center coordinates, thus simulating and analyzing inter-fraction and intra-fraction motion of lens in radiotherapy. Results Both left and right lens moved in different degree during both interor intra-fraction phase. The range of lens movement was larger in inter-fraction than in intra-fraction phase in all directions. Conclusion When radiotherapy is given in the free state, considering the distance of lens movement alone in inter- and intra-fraction and without considering the setup error, the lens planning organs at risk should increase l.5mm outside the lens boundary.