Dosimetry evaluation for CT guided 125I seeds implantation assisted by three-dimensional-printing coplanar coordinate template in chest malignant tumor / 中华核医学与分子影像杂志

ABSTRACT

Objective To verify the accuracy of three-dimensional printing coplanar coordinate template (3D-PCCT) technology for 125I seeds implantations in chest tumor at dosimetry level.Methods From January 2016 to June 2017,a total of 22 patients (15 males,7 females;median age 62 years) with chest tumors who received 3D-PCCT assisted 125I seeds implantation in Peking University Third Hospital were enrolled in this retrospective study.There were 8 patients with primary lung cancer and 14 with metastatic carcinoma.The sites for implantation included lung (12 cases),mediastinum (2 cases) and chest wall (8 cases).The prescribed dose was 110-180 Gy.The preoperative plan design,puncture and seeds implantation guided by template were carried out and the dose distribution of postoperative plan was compared with that of preoperative plan.Dose parameters included dose delivered to 90％ gross tumor volume (D90),minimum peripheral dose,the percentage of GTV receiving 100％ prescription dose (V100),the percentage of GTV receiving 150％ prescription dose (V150),conformity index,external index of target volume,uniformity index,D2 cm3 of spinal cord and aorta,and V20 of affected side lung.Wilcoxon signed rank test was used to analyze the data.Results The median D90 was 150.4(125.6,187.0) Gy.Postoperative D90 was higher than the prescribed dose in 68％ (15/22) cases.For median value of most parameters,there were no significant differences between the postoperative plans and preoperative plans (all P＞0.05) except for the actual V100,which was lower than the preplanned (95.5％ vs 97.2％;P=O.040).Conclusion 3D-PCCT could provide good accuracy in 125I seeds implantation for chest tumor.