The advantages of intraoperative TPS real-time planning in treating retroperitoneal metastatic carcinoma with 125I seed brachytherapy / 介入放射学杂志

ABSTRACT

Objective To discuss the necessity and feasibility of intraoperative use of treatment planning system (TPS) to make real-time planning for the treatment of retroperitoneal metastatic carcinoma with CT-guided 125I seed brachytherapy.Methods The clinical data of 20 patients with retroperitoneal lymph node metastases,who received CT-guided 125I seed brachytherapy during the period from January 2013 to December 2015,were retrospectively analyzed.The patients were divided into group A (n=10) and group B (n=10).The intraoperative TPS was employed to formulate the real-time planning for the patients of group A,while real-time planning was not adopted for the patients of group B.The quality verification of preoperative planning and postoperative effect was conducted for the patients of both groups.Comparing the preoperative and postoperative absorbed dose,the minimum absorbed dose (D90) error percentage of 90％ target volume,the error percentage of the covered volume by 90％ prescription dose to the target volume (V90),the error percentage of the covered volume by 100％ prescription dose to the target volume (V100),and the error percentage of the covered volume by 150％ prescription dose to the target volume (V150) were calculated in all patients of both groups,and the results were statistically analyzed.Results The mean error percentage of D90,V90,V100,V150 in group A were (-1.30±6.80) Gy,(-0.60±2.10)％,(-0.47±2.70)％ and (89.60±282.00)％ respectively,which in group B were (-9.33±46) Gy,(11.50±13.7)％,(-13.40±15.90)％ and (10.37±2.00)％ respectively.The differences in the error percentage of D90,V90 and V100 between group A and group B were statistically significant (P＜0.05 in all),while no statistically significant difference in the error percentage of V150 existed between group A and group B (P＞0.05).Conclusion The use of intraoperative TPS real-time planning can significantly improve the consistency of target region dose before and after seed implantation and make the dose distribution more reasonable,which is of great value for the standardization of CT-guided 125I seed brachytherapy of retroperitoneal lymph node metastases.