Application of 3D Printing Template Combined with CT Guidance in Implantation and Radiotherapy of Locally Advanced Non-Small Cell Lung Cancer

Objective: To explore the clinical application of 3D printing template combined with CT guidance in radiotherapy of interstitial implantation of non-small cell lung cancer. Methods: A retrospective study was conducted on 20 patients with lung cancer treated with radiotherapy with brachythe-rapy. In the experimental group, 10 patients used 3D printing template for short-range interstitial implantation radiotherapy. The implantation needle path was designed by the pre-planning method based on CT images, and the individual template entity and implantation needle path were created by 3D printing technology, and finally guided by CT placing the template below. The con-trol group consisted of 10 cases of doctors’ freehand implantation radiotherapy treatment plan. The freehand implantation method was not pre-planned and the direction of the implant needle was determined by the experience of the operating doctor. The differences in dosimetry and operational safety were calculated when the prescribed doses of the experimental group and the control group were 15, 30, 45 and 60 Gy, respectively. Results: The D 98 , D 95 , and D 90 of the planned target volume of the template group were higher than those of the freehand implantation method, and the difference was statistically significant (P < 0.05); The template group had lower V 5 , V 20 , V 30 , and D mean of the organ at risk lungs than the freehand implantation group (P < 0.05). The template group used a total of 83 implantation needles, the number of misses was 1 time, and there was no incident of normal tissue penetration by the implantation needle. In the unarmed group, 97 times of needle insertion were used, 4 times of missed targets, and 4 normal tissue piercing events were observed. Conclusion: The 3D printing individualized template combined with the CT guided method has dosimetry advantages over the freehand implantation method, and is easy to operate, has good repeatability, short implantation time, fewer implant needles, and the actual treatment can meet the pre-planned dose design requirements, which can improve the clinical work efficiency.