Objective: To compare the preoperative and postoperative dosimetric parameters in the treatment of spinal metastasis, and to verify the accuracy of 3D-printing non-coplanar template (3D-PNCT) combined with CT-guided ¹²⁵I seed implantation for the treatment of spinal metastasis. Methods: The treatment plans of 7 patients with spinal metastasis (9 lesions) from 2016 to 2018 receiving 3D-PNCT in combination with CT-guided ¹²⁵I seed implantation were retrospectively analyzed. The dosimetric parameters including homogeneity index (HI), conformal index (CI), external index (EI), dose of 90% target volume(D₉₀), mPD, volume percent of 100%, 150%, and 200% prescribed dose V₁₀₀、V₁₅₀、V₂₀₀ and D_2cm³ of spinal cord were compared before and after operation. The british columbia cancer ageny particle implantation quality evaluation standard was applied to evaluate the quality of implantation. Results: The HI, EI and CI, D₉₀, mPD, V₁₀₀, V₁₅₀, V₂₀₀ and D_2cm³ of spinal cord did not significantly differ before and after the plan (all P>0.05). Five were evaluated as excellent and 4 were assessed as good. Conclusion The postoperative dosimetric parameters of 3D-PNCT combined with CT guided ¹²⁵I seed implantation of spinal metastasis are basically consistent with preoperative dosimetric parameters. The postoperative plans are evaluated as excellent or good, suggesting that the technology has a good therapeutic accuracy in the treatment of spinal metastasis.

Objective To analyze the qualified rate of the fiducial markers during 3D-printing co-planar template assisted CT-guided implantation in stereotactic body radiation therapy by CyberKnife,and to explore the cause of the unavailable markers in order to provide the reference for the fiducial implantation,treatment planning and radiotherapy delivery.Methods From March to December 2017,a total of 52 cases were planned to stereotactic body radiation therapy(SBRT) using CyberKnife by fiducial tracking,and the fiducial markers were implanted based on CT-guided 3D-printing co-planar template,including 22 in lung,12 in liver,5 in mediastinal lymph node,8 in retroperitoneal lymph node,3 in pancreas,each in celiac and pelvic lymph nodes,respectively.Except 7 cases not fit for CyberKnife treatment,45 cases finished the treatment of CyberKnife,but there were 3 cases changed to spine tracking due to unqualified fiducial markers.The number of fiducial markers used and the qualified rate of fiducial markers were analyzed,and the cause of unqualified fiducial markers was studied.Results A total of 131 fiducial markers were impanted into 42 cases who finally received the treatment of CyberKnife by fiducial tracking,including 85 fiducial markers qualified (64.89％) and 46 fiducial markers unqualified (35.11％).The main causes of the unqualified fiducial markers varied,including outrange of rigidity error(26.08％),fiducial markers unavailable(41.31％),and other (32.61％).Conclusions The 3D-printing co-planar template assisted CT-guided implantation could reduce the number of puncture needles used,help to decrease the risk of puncture and trauma and the incidence of complications after the fiducial markers implantation.However,the fiducial markers implanted by this way would be abandoned by a variety of causes and should be taken into account before the fiducial markers implantation.

Objective To compare the dose distribution of postoperative plans with preoperative plans of 3D-printing template (coplanar and non-coplanar) assisted and CT-guided 125I seed implantation for the treatment of soft tissue sarcoma,and to explore the accuracy of treatment at dosimetry level.Methods From December 2015 to July 2017,19 patients with soft tissue sarcoma (a total of 25 lesions)were treated with 3D printing template assisted and CT-guided 125I seed implantation in Peking University Third Hospital.All patients underwent preoperative assessment,CT simulation orientation,preoperative planning,3D-template printing,3D-template reduction,needle and seed implantation,postoperative dosimetry assessment,postoperative care and follow-up.The preoperative and postoperative dosimetric parameters were conpared.Ten cases of soft tissue sarcoma in superficial trunk or limbs were screened.Preoperative planning of coplanar template and non-coplanar template were designed respectively.The dosimetric parameters of preoperative planning guided of two templates were compared.Results Twentyfive 3D-printing templates were designed and constructed,and 25 lesions were totalled.There was no statistical difference between preoperative and postoperative dosimetric parameters.There was no statistical difference of the preoperative plan's dosimetric parameters between coplanar and non-coplanar in soft tissue sarcoma of superficial trunk/limbs.Conclusions The validation of actual dose distribution in postoperative plans assisted by 3D-printing template in 125I seed implantation showed that most of parameters could meet the expectation of preoperative plans,which indicated the improvement in accuracy for this new modality.For soft tissue sarcoma located in the superficial trunk/limbs,it was recommended to select the 3D-printing coplanar template firstly.

Objective To investigate the feasibility of 3D-printing coplanar coordinate template (3D-PCT) for guiding 125I radioactive seed implantation in the treatment of pelvic wall recurrence of cervical cancer on ensuring the accuracy of dose.Methods From Oct 2016 to Dec 2017 in Peking University Third Hospital,totally 10 patients with pelvic wall recurrent cervical cancer after radiotherapy were treated with 125I radioactive seed implantation assisted by 3D-PCT.The median age was 53.5 years old (37-71 years old).KPS score of the cohort were more than 70.All patients had received pelvic radiation therapy previously.The median volume of the lesion was 31.9 cm3 (3.5-58.0 cm3).The prescription dose was 120-180 Gy.The activity of seeds was 0.55-0.67 mCi(1 Ci =3.7 × 1010Bq),while the number of seeds was 12-81 (median 50) on preoperative plan.Radioactive seeds implantation was performed under 3D-PCT guidance according to the preoperative plan.The actual number of implanted seeds was 53 (10-82).Dosimetry parameters of preoperative plan and postoperative plan including D90,D100,V100,V150,V200,external index (EI),conformal index (CI),heterogeneity index (HI),and organat-risk doses of D2 cm3,D1 cm3 and D0.1 cm3 were compared using the nonparametric test.Results The seed number of postoperative plan was more than that of preoperative plan (Z =-2.255,P ＜ 0.05),but all of the dosimetric parameters showed no significant difference (P ＞ 0.05).D2 cm3 and D1 cm3 of rectum for postoperative plan were lower than that of preoperative plan (Z =-2.100,-2.240,P ＜ 0.05),while other dose parameters of normal tisssues showed no statistically significant difference (P ＞ 0.05).Conclusions Assisted by 3D-PCT for 125I radioactive seed implantation in pelvic wall recurrence of cervical cancer,the actual postoperative dose could meet the requirement of the preoperatie plan through the intraoperative optimization of dose.3D-PCT could ensure the precise of delivered dose of 125I radioactive seed implantation.

Objective To compare the dose distributions of postoperative plans with preoperative plans for 3D printing guide plate assist radioactive seeds implantations, explore the effects of the technology for seeds implantations in dosimetry level. Methods From January 2016 to December 2016, a total of 42 patients of local recurrent malignant tumor of head and neck received 3D printing guide plate assist radioactive seeds implantations in in Peking University Third Hospital, and included in the retrospective study. The prescribed dose was 110 -160 Gy. All patients carried out preoperative planning design, individual guide plate production, and compared the dose distribution of postoperative plan with preoperative plan. Dose parameters include D90 , mPD, V100 , V150 , V200 , CI, EI and HI. Statistical method was paired t-test. Results A total of 423D printing individual templates were produced. The mean GTV volume of all patients was 28. 6 cm3 , and mean D90 of postoperative target area ( GTV) was 142. 6 Gy. For postoperative plans, the mean D90 , mPD, V100 , V150, V200 was 142. 6 Gy, 77. 3 Gy, 92. 48％, 68. 40％and 42. 98％, respectively, and 144. 5 Gy, 70. 2 Gy, 91. 45％, 63. 12％ and 34. 74％, respectively, in preoperative plans. Except mPD, V150, V200(t= -2. 166, -2. 863, -4. 778, P<0. 05), there was no significant difference between the two groups. Conclusions 3D printing guide plate could provide good accuracy for positioning and direction. For local recurrent malignant tumor of head and neck, the actual dose distributions in postoperative validations were close to the expectations of preoperative plans which mean the improvement of accuracy in treatment.

Objective To investigate the utilization rate of gold fiducial markers and reasons for abandonment of gold fiducial markers in the CyberKnife VSI System, and to provide reference data for implantation of gold fiducial markers and radiotherapy planning. Methods From March to August,2017,a total of 47 patients had gold fiducial markers implanted or pasted. In those patients, 42 patients had gold fiducial markers implanted,including 32 receiving computed tomography(CT)-guided 3D-printing coplanar template assisted implantation, 1 receiving CT-guided 3D-printing non-coplanar template assisted implantation,1 receiving CT-guided implantation,and 8 receiving ultrasound-guided implantation. A total of 44 patients received the CyberKnife treatment, including 2 patients who failed to use gold fiducial markers and were treated with spine tracking instead and 3 patients missing the treatment for other reasons. The numbers of utilized and abandoned gold fiducial markers were recorded for calculation of the utilization and abandonment rates. The reasons for abandonment of gold fiducial markers were analyzed and classified. Results A total of 134 gold fiducial markers were implanted into or pasted to the 44 patients.In all the gold fiducial markers, 111 were utilized and 23 abandoned, yielding a utilization rate of 82.8% and an abandonment rate of 17.2%.The reasons for abandonment of gold fiducial markers included large rigidity error(26.1%), unqualified implanted fold fiducial markers(17.4%), displacement of gold fiducial markers(26.1%), and others(30.4%). Conclusions Compared with the CT-guided or ultrasound-guided implantation of gold fiducial markers, the CT-guided 3D-printing coplanar or non-coplanar template assisted implantation of gold fiducial markers requires only two puncture needles for each implantation and implants two gold fiducial markers by a single needle,which reduces the number of puncture needles,risk of puncture-induced injury,and incidence of complications after implantation. Not all the gold fiducial markers implanted by a variety of ways will be utilized. Some gold fiducial markers will be abandoned for different reasons,which should be taken into account during implantation of gold fiducial markers.

Objective To evaluate the clinical efficacy and safety of CT-guided 125 I seed implantation in the treatment of recurrent head and neck tumors after radiotherapy. Methods Clinical data of 101 patients who received CT-guided radioactive 125 I seed implantation for recurrent head and neck cancer after radiotherapy from 2007 to 2015 were retrospectively analyzed. The median accumulated dose of external radiotherapy was 66 Gy and the median dose after seed implantation (D90) was 117 Gy. The local progression-free survival and overall survival were analyzed by Kaplan-Meier method. Univariate analysis was performed by log-rank test and multivariate analysis was conducted by using Cox regression model. Results The median follow-up time was 12. 2 months. The 5-year local progression-free survival rate was 26. 6％.The 5-year overall survival rate was 15. 5％. Univariate analysis demonstrated that age,pathological type,implantation site,lesion volume,D90 and short-term efficacy were correlated with local control,and KPS score,lesion volume ,D90,and short-term efficacy were associated with survival (all P<0. 05). Multivariate analysis revealed that pathological type,lesion volume ,D90 and short-term efficacy were independent factors related to local control (P= 0. 000, 0. 002,0. 003 and 0. 014).In terms of the adverse events,skin/ mucosal ulceration was observed in 25. 7％ and pain occurred in 13. 9％ of all patients. No correlation was noted between the adverse events and dose.Conclusions CT-guided radioactive 125 I seed implantation is an efficacious and safe treatment of recurrent head and neck tumors after radiotherapy. Non-squamous carcinoma,small lesion volume and high dose (D90) indicate excellent local control.

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.

Objective: To investigation HER2 status in gastric adenocarcinoma of Chinese and contributing factors to the HER2 expression. Methods: HER2 status of 40 842 gastric adenocarcinomas and clinical data were retrospectively collected from 23 hospitals dated from 2013 to 2016. The association between HER2 positivity and clinicopathologic features was analyzed. Results: Of the 40 842 patients the median age was 62 years, the male female ratio was 2.6∶1.0. The rate of HER2 positivity was 8.8% (3 577/40 842). HER2 expression was related to the tissue type, tumor location, Lauren classification and tumor differentiation (P values: 0.009, 0.001, <0.01 and <0.01, respectively). Different HER2 expression status was observed between primary and recurrent tumors in 7.6% (48/635) cases. The rates of HER2 positivity ranged from 2% to 10% among different institutions. The rates of HER2 FISH amplification were dramatically different among the 23 hospitals (0-100%) with an average rate of 10% (810/8 156) in patients with HER2 IHC 2+ . Conclusions HER2 expression is associated with clinicopathologic characteristics. HER2 re-assessment of tumor tissue and use of in situ hybridization techniques increase HER2 positivity. The current retrospective study should reflect the HER2 status in gastric adenocarcinoma of Chinese patients.

Objective To compare the pre-and post-operative tumor target volume and to examine the consistency in physical dosimetric parameters of organs at risk (OAR) following 3D-printed coplanar template (3D-PCT)-assisted and CT-guided radioactive seed implantation.Methods The 3D-printed coplanar template was designed using a computer software, and the coordinate system was established where the center was used as the basis for setting the x axis and y axis.Crosses defining the center of treatment were drawn on the patient''s body and matched with the corresponding central point, x axis, and y axis of the coplanar template.3D-PCT-assisted and CT-guided radioactive seed implantation was performed based on the pre-operative plan, and the pre-operative, operative, and post-operative plans were designed to evaluate the target tumor volume and the normal dose received by the tissues.In addition, dosimetric parameters, including D90(minimum dose received by 90% of the gross target volume), V100, V150, V200(percentage of GTV that received 100%, 150%, and 200% of the prescribed dose, respectively), minimum peripheral dose (MPD), conformal index (CI), external index (EI), and homogeneity index (HI) in the pre-operative and post-operative plans were also assessed and compared using the Wilcoxon test. Results Fourteen patients treated in our institution from August to October, 2016 were included in this study. The median age of the patients was 61.5 years, and the median Karnofsky Performance Scale score was 80. A total of 14 lesions from the 14 patients were treated by seed implantation in the neck (n=4), chest (n=3), abdomen (n=5), and pelvis (n=2). Of the 14 patients that underwent implantation, 8 had previously received radiation therapy, and 6 had not received radiation therapy. Dosage optimization was performed for all patients during the operation. The median activity of the implanted seeds was 0.625 mCi (0.55-0.75 mCi,1 Ci=3.7×1010 Bq), and the preoperatively planned median number of needling and implanted seeds were 9(4-34) and 45.5(10-162), respectively. However, the actual median number of needling and implanted seeds were 9.5(4-34) and 45.5(10-162), respectively. Dosimetric analysis showed that there were no significant changes in tumor volume (P=0.135), D90(P=0.208), MPD (P=0.104), V100(P=0.542), V150(P=0.754), V200(P=0.583), CI (P=0.426), EI (P=0.326), and HI (P=0.952) after implantation. Conclusions 3D-PCT guidance and dosage optimization can result in good consistency between pre-and post-operative plans for radioactive seed implantation. 3D-PCT is a convenient and cheap technique suitable for large-scale clinical application.