Application Of 3D Printing Vaginal Personalized Model In High Dose Rate 3-dimensional Brachytherapy Of Cervical Cancer

Objective:To explore the application value of using 3D printing technology to create individualized vaginal molds for brachytherapy in high-dose-rate three-dimensional cervical cancer through reverse engineering of needle placement.Methods:Prospectively,11 patients with cervical cancer were treated with 3D printing intracavitary/interstitial brachytherapy（3DP-IC/IS BT）using 3D printing to create individualized vaginal molds.All patients were performed brachytherapy after completion of external beam radiotherapy（EBRT）.Each patient was treated with BT five times,the prescription dose was 6Gy/F,and combined external radiation to achieve a total HRCTVD₉₀of at least 85Gy（EQD2）,which was performed once or twice a week,two of them were freehand IC/IS BT,and three were 3DP-IC/IS BT.The relevant planning parameters（bladder,rectum,sigmoid colon,and small intestine）and target conformity index（CI）for HR-CTV and OARs were compared between the groups.Results:There were significant advantages in the 3DP-IC/IS BT group compared with the freehand IC/IS BT group:HRCTVD₉₀（629.40±19.34c Gy vs.613.03±15.93c Gy,p=0.002）,D₉₅（580.74±18.31c Gy vs.567.44±23.94c Gy,p=0.032）,bladder D_2cc（431.11±23.27c Gy vs.458.07±23.27c Gy,p<0.001）,bladder D_1ccand bladder D_0.1cc.There was no statistically significant difference（p>0.05）between the two groups in rectal D_2cc（352.30±42.42c Gy vs.361.29±42.42c Gy,p=0.470）,sigmoid colon D_2cc（236.73±78.95c Gy vs.246.50±58.17c Gy,p=0.621）,CI（0.79±0.04 vs.0.79±0.039p=0.773）,HR-CTV V₁₀₀,V₂₀₀,D₉₈,D₁₀₀and other OARs parameters（p>0.05）.Conclusion:Compared with IC/IS BT,3DP-IC/IS BT has apparent advantages with simple operation and high safety.In addition,individualized mold helps to improve the tumor target area’s radiation dose while meeting the dose-limiting requirements for organs at risk and reduces the clinical proficiency requirements for operating physicians.