| Objective Since the 21 st century,Chinese scholars have widely used radioactive particle implantation in various solid tumors.However,except prostate cancer,the particle implantation methods of other solid tumors lack a unified standard,which requires high experience and is difficult to promote.In this study,a treatment planning system(TPS)and a desktop 3D printer were used to print 125 I radioactive particle implantation templates of polylactic acid(PLA)for lung cancer.The consistency of dosimetric parameters before and after surgery was initially evaluated to verify its accuracy and safety,especially the feasibility of its clinical application.Methods A retrospective research method was used to compare 42 patients with lung cancer who were implanted with radioactive particles with or without PLA templates from January 2018 to December 2019.Among them,21 patients who used 3D printed templates to guide radioactive particle implantation were classified as template groups,and guided by CT.21 patients who implanted radioactive particles by hand were classified as the control group.Regarding the steps of formulating the preoperative plan and postoperative dose verification,the control group and the template group are the same,except that there are no steps related to the design and manufacture of the 3D printed PLA template.CT image data were imported into the particle implantation brachytherapy Treatment Planning System(TPS)v6.0 before surgery.The target area and neighboring organs at risk were outlined,prescription dose and particle activity were set,particle interpolation path and particle number distribution were generated,and dose volume histogram(DVH)was generated.Until the plan meets the dosagerequirements,the template was outputed in STL format to a 3D printer for printing,and the dosimetric parameters such as D90,V90,V100,and V150 were recorded.During the procedure,puncture was performed with the help of CT guidance and 3D printed templates,and all particles were implanted at one time according to the preoperative plan.A CT scan was performed immediately after the operation and postoperative verification was performed to record the above dosimetric parameters.The British Columbia Cancer Agency(BCCA)criteria were used as dosimetric evaluation criteria,and they were divided into 4 groups of excellent,good,moderate,and poor according to postoperative D90 and V100.The postoperative implant quality and D90,V90,V100,V150 and other parameters of the two groups of patients were compared and analyzed,and the recent complications were compared.Results Twenty-one patients with lung cancer had good resetting during operation.The PLA surgical template effectively guided the implantation of radioactive particles in lung cancer.Quality of surgery in the template group: excellent: 18 cases(85.71%,18/21);good: 2 cases(9.52%,2/21);medium: 1 case(4.77%,1/21);poor: 0 cases(0 /21);control group surgery quality: excellent: 10 cases(47.62%,10/21);good: 6 cases(28.57%,6/21);medium: 5 cases(23.81%,5/21);poor: There were 0 cases(0/21),and the difference between the two groups was statistically significant(P <0.05).The average operation time in the template group was 61.23 ± 12.33 minutes,and the average operation time in the control group was 68.81 ± 24.19 minutes.The operation time of the template group was reduced by about 11.02% compared with the control group.There was a statistically significant difference between the two groups(P <0.05).The number of implanted needles and particles in the template group were 11.27±3.17 needles,57.62 ±19.12,and the number of implanted needles and particles in the control group were 12.34±4.91 needles and 58.29±16.96,respectively.There was no statistical difference between the two groups.Significance(all P>0.05).The mean D90 before and after surgery in the template group were(120.98±10.84)Gy,(119.29±12.28)Gy,and P = 0.127.There was no significant difference before and after surgery.The D90 before and after operation in the control group were(122.29±11.38)Gy,(110.29±10.34)Gy,and P = 0.004.The difference before and after surgery was statistically significant.The mean V90 of the template group was(92.55%±1.59%)after operation,and the V90 of the control group was(89.52%±3.49%).The comparison between the two groups was P=0.005,and the difference was statistically significant.The mean V100 in the template group was(87.61%±2.37%)in the postoperative group,and the average V100 in the control group was(80.52%±3.22%).The difference between the two groups was P=0.001,and the difference was statistically significant.The mean V150 in the template group was(62.62%±2.65%)in the postoperative group,and the average V100 in the control group was(59.69%±1.68%).The comparison between the two groups was P=0.004,and the difference was statistically significant.The local control rate and effective rate at 6months after treatment in the template group were 90.48%和 57.14%,respectively.In the control group,the local control rate and effective rate at 6 months after treatment were 42.86%和 19.05%,respectively,and the differences were statistically significant(P<0.05).There was no significant difference in complications between the two groups.(P>0.05).Conclusion Compared with CT-guided 125 I radioactive particle interstitial implantation,CT-guided 3D printed template-assisted 125 I radioactive particle interstitial implantation has more professional advantages in the treatment of lung malignancies: First,significantly improve the implantation accuracy of the path and the degree of implementation of the preoperative plan make the dosimetric evaluation of preoperative and postoperative more homogeneous.Second,it not only shortens the overall operation time,but also significantly improves the accuracy of the particles inthe tumor.It also meets the dosimetry requirements and lays the foundation for the safety,standardization and standardization of surgery. |
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