Objective:Investigate the safety and feasibility of using the new self-designed implanting applicator in vaginal three-dimensional intracavitary brachytherapy after hysterectomy for gynecological cancer, and to explore the clinical value of the self-designed implanting applicator.Methods:Sixty-two gynecological cancer patients who underwent brachytherapy in Sun Yat-sen University Cancer Center were selected in this study. Each patient received three-dimensional intracavitary brachytherapy because of the indication of postoperative radiotherapy. Each patient was treated with different types of self-designed implanting applicators according the condition of postoperative vagina,and the vaginal tube and implant needle were placed in the template according to the preset channnel. Based on the actual CT images, the high-risk clinical target volume (HR-CTV), and organs at risk were defined according to unified target area delineation criteria and then the brachytherapy plan was conducted. The prescription dose of high-risk clinical target volume (HR-CTV) was 5.5 Gy/time. The parameters such as target area, organs at risk volume and irradiated dose were evaluated by DVH diagram.Results:Sixty-two patients successfully completed brachytherapy under the guidance of self-designed implanting applicator. A total of 140 implantation treatments were performed. The total average dose of HR-CTV D90% was (575.48±22.30) cGy, the mean dose D 2cm3 of bladder, rectum and sigmoid colon were (328.69±102.71), (369.14±46.59) and (27.28±71.27) cGy, the small intestine did not drop the target area, so there was no statistics. There was statistical significance between target volume and organs at risk dose ( P<0.05). Conclusions:The new self-designed implanting applicator has obvious clinical advantages in vaginal three-dimensional intracavitary brachytherapy after hysterectomy for gynecological cancer, meets the requirements of the preset planning dose,and it is sample to operate and highly safe,which indicated a bright future of the clinical application.

Objective To investigate the dosimetric difference between manual and inverse optimization in 3-dimensional (3D) brachytherapy for gynecologic tumors. Methods This retrospective study was conducted among a total of 110 patients with gynecologic tumors undergoing intracavitary combined with interstitial brachytherapy or interstitial brachytherapy. Based on the original images, the brachytherapy plans were optimized for each patient using Gro, IPSA1, IPSA2 (with increased volumetric dose limits on the basis of IPSA1) and HIPO algorithms. The dose-volume histogram (DVH) parameters of the clinical target volume (CTV) including V200, V150, V100, D90, D98 and CI, and the dosimetric parameters D2cc, D1cc, and D0.1cc for the bladder, rectum, and sigmoid colon were compared among the 4 plans. Results Among the 4 plans, Gro optimization took the longest time, followed by HIPO, IPSA2 and IPSA1 optimization. The mean D90, D98, and V100 of HIPO plans were significantly higher than those of Gro and IPSA plans, and D90 and V100 of IPSA1, IPSA2 and HIPO plans were higher than those of Gro plans (P<0.05), but the CI of the 4 plans were similar (P>0.05). For the organs at risk (OARs), the HIPO plan had the lowest D2cc of the bladder and rectum;the bladder absorbed dose of Gro plans were significantly greater than those of IPSA1 and HIPO (P<0.05). The D2cc and D1cc of the rectum in IPSA1, IPSA2 and HIPO plans were better than Gro (P<0.05). The D2cc and D1cc of the sigmoid colon did not differ significantly among the 4 plans. Conclusion Among the 4 algorithms, the HIPO algorithm can better improve dose coverage of the target and lower the radiation dose of the OARs, and is thus recommended for the initial plan optimization. Clinically, the combination of manual optimization can achieve more individualized dose distribution of the plan.

Objective To investigate the dosimetric difference between manual and inverse optimization in 3-dimensional (3D) brachytherapy for gynecologic tumors. Methods This retrospective study was conducted among a total of 110 patients with gynecologic tumors undergoing intracavitary combined with interstitial brachytherapy or interstitial brachytherapy. Based on the original images, the brachytherapy plans were optimized for each patient using Gro, IPSA1, IPSA2 (with increased volumetric dose limits on the basis of IPSA1) and HIPO algorithms. The dose-volume histogram (DVH) parameters of the clinical target volume (CTV) including V200, V150, V100, D90, D98 and CI, and the dosimetric parameters D2cc, D1cc, and D0.1cc for the bladder, rectum, and sigmoid colon were compared among the 4 plans. Results Among the 4 plans, Gro optimization took the longest time, followed by HIPO, IPSA2 and IPSA1 optimization. The mean D90, D98, and V100 of HIPO plans were significantly higher than those of Gro and IPSA plans, and D90 and V100 of IPSA1, IPSA2 and HIPO plans were higher than those of Gro plans (P<0.05), but the CI of the 4 plans were similar (P>0.05). For the organs at risk (OARs), the HIPO plan had the lowest D2cc of the bladder and rectum;the bladder absorbed dose of Gro plans were significantly greater than those of IPSA1 and HIPO (P<0.05). The D2cc and D1cc of the rectum in IPSA1, IPSA2 and HIPO plans were better than Gro (P<0.05). The D2cc and D1cc of the sigmoid colon did not differ significantly among the 4 plans. Conclusion Among the 4 algorithms, the HIPO algorithm can better improve dose coverage of the target and lower the radiation dose of the OARs, and is thus recommended for the initial plan optimization. Clinically, the combination of manual optimization can achieve more individualized dose distribution of the plan.