[The dosimetry comparison study between 3D print template and free-hand guided of precision (125)I seeds implantation on superficial metastatic carcinoma].

ABSTRACT

Objective: To compare the dose difference of (125)I seeds implantation on superficial metastatic carcinoma between 3D print template guided operation and traditional implantation. To investigate the accuracy of seeds implantation according preplan guided by 3D print template. Methods: A total of 21 cases of patient with 27 lesions underwent (125)I seeds implantation from January 2015 to May 2018 in Hebei General Hospital were analyzed retrospectively. In which, ten lesions underwent seeds implantation guided by 3D print template (template group) and 17 lesions underwent free-hand traditional implantation (traditional group). All patients had been fixed as the position of operation and then performed CT scan. After preplan was designed, the 3D templates were printed in template group. Postplan was performed after the operation.The dose volume histogram, D90 was calculated. The D90 pre and post operation were collected and compared in each group. The difference of D90 and the percentage difference of D90 between pre and post operation were calculated by the formula D90d=D90post-D90pre, D90d%=(D90post-D90pre)/D90pre×100%, and compared the difference between two groups. Results: The mean D90 pre and post operation in template group were (92±26) and (93±27) Gy respectively, t=-0.749, P=0.473. The mean D90 pre and post operation in traditional group were (104±29) and (104±26) Gy respectively, t=-0.139, P=0.891. The difference of D90 in two groups were (3.1±2.4) and (10.0±8.7) Gy, Z=-2.5, P=0.012. The percentage difference of D90 in two groups were 3.1%±1.9% and 9.5%±7.9%, Compared with the traditional group, the template group had smaller fluctuations, and the difference was statistically significant (Z=-2.7, P=0.006) (all P<0.05). Conclusions: The dose parameters of 3D template guided seeds implantation between postplan and preplan are nearly consistent.3D template has good repeatability, which provides a theoretical basis for the popularization of 3D printing technology.