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Objective:To explore the accuracy of CT-guided 125I seed implantation assisted by a navigation system and 3D-printing template in the treatment of recurrent malignant pelvic tumors by comparing pre-plan and intraoperative physical dosimetric parameters. Methods:This study involved 15 patients with recurrent malignant pelvic tumors who received CT-guided radioactive 125I seed implantation assisted by a navigation system and 3D-printing template in the Peking University Third Hospital from Dec 2018 to Feb 2020.Seven of the patients had cervical cancers, seven had rectal cancers, and one had prostate cancer.The median age was 55 years (34-84 years old). The prescription dose was 100-150 Gy.The pre-plan and post-implant data were compared, including the number of implanted seeds, implantation needle number, and some dosimetric parameters such as the minimum prescription doses delivered to 90% and 100% of target volume( D90, D100), mean percentages of volume receiving 100%, 150%, and 200% of the prescription doses( V100, V150, and V200), conformity index(CI), external index(EI), and homogeneity index(HI)of the target volume. Results:The median lesion volume was 29.20 cm 3, the median seed number was 54, and the median D90 was 150 Gy.The post-implant V150 was lower than pre-plan V150 (64.1% vs. 67.1%, t=2.937, P=0.011), and the post-implant mean HI was higher than pre-plan HI (32.01% vs. 26.68%, t=-2.950, P=0.011). There were no significant differences in other dosimetric parameters before and after seed implantation. Conclusions:With CT-guided radioactive seed implantation assisted by a navigation system and 3D-printing template in the treatment of recurrent malignant pelvic tumors, the actual postoperative dose could meet the preoperative plan requirement, ensuring the accuracy and consistency of the dose delivered.
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Objective:To compare preoperative planning parameters between non-coplanar and coplanar template-assisted radioactive seed implantation in the treatment of pancreatic cancers, in order to guide clinical application.Methods:Patients with pancreatic cancers who received external irradiation in the Peking University Third Hospital from Jan 2017 to May 2019 were selected.Their image information was imported into the brachytherapy planning system, and the non-coplanar plan and coplanar plan were designed individually.Each patient′s prescription dose was set to 110 Gy, and the activity of the radioactive seeds were 0.4 mCi(1 Ci=3.7×10 10Bq), respectively.For the two plans, the dose distribution was optimized and dosimetric parameters were compared, including the implantation needle number, the implanted seed number, the minimum prescription doses delivered to 90% and 100% of the target volume ( D90 and D100), mean percentages of volume receiving 100%, 150% and 200% of the prescription doses ( V100, V150 and V200), conformity index (CI), external index (EI), and homogeneity index (HI) of the target volume, as well as the doses of 2 cm 3 and 5 cm 3 ( D2 cm 3 and D5 cm 3) of the surrounding normal organs such as the small intestines, colon, duodenum, stomach, and spinal cord. Results:The implantation needle number in the coplanar plan was slightly higher than that in the non-coplanar plan, namely 18.63 vs. 16.45 ( t=-3.239, P <0.05). The implanted seed number was equivalent, namely 90.2 vs. 91.01, with no statistical difference ( P>0.05). There was no significant difference between D90, D100, V100, V150, V200, CI, EI, and HI in the target area of the two plans ( P>0.05). Meanwhile, there was no obvious difference in D2 cm 3 and D5 cm 3 of normal organs including the small intestines, colon, duodenum, stomach, and spinal cord ( P>0.05). Conclusions:With both the coplanar plan and the non-coplanar plan, the prescription doses can be achieved and meanwhile, there are very small differences in the doses of normal organs.Given that 3D-printing non-coplanar and coplanar templates have their own characteristics, it is necessary to choose them according to specific situations.
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Objective:To verify the accuracy and feasibility of radioactive 125I seed implantation assisted by an optical navigation system and a 3D-printing non-coplanar template in the treatment of recurrent head and neck cancers. Methods:A total of 12 patients with recurrent head and neck cancer treated with radioactive 125I seed implantation assisted by an optical navigation system and 3D-printing non-coplanar template were enrolled from Dec 2018 to Dec 2019.The pre-plan and post-implant implantation needle number and implanted seed number were recorded.Meanwhile, their dosimetric parameters were compared, including D90, minimum peripheral dose (MPD), V100, V150, V200, conformity index (CI), external index (EI), and the homogeneity index (HI) of the target volume. Results:The median lesion volume was 31.5 cm 3, the median number of seeds was 61.5, and the median prescription dose was 130 Gy.The means of the pre-plan D90, MPD, V100, V150 and V200 were 134.2, 64.6, 93.3, 75.3 and 39.3 Gy, respectively, while those of post-implant D90, MPD, V100, V150, and V200 were 146.7, 68.94, 97.47, 80.40 and 48.30 Gy, respectively, with no statistically significant difference ( P>0.05). Meanwhile, there was no statistically significant difference between the pre-plan and post-implantation needle number, implanted seed number, CI, HI, and EI ( P>0.05). In terms of postoperative dose quality assessment, eight cases were rated excellent (66.6%) and four cases were rated good (33.3%). Conclusions:Radioactive 125I seed implantation assisted by an optical navigation system and 3D-printing non-coplanar template can be accurately performed in the treatment of recurrent head and neck cancer, with good consistency between pre-plan and post-implant dosimetric parameters and thus of prospective potential in clinical application.
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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 D2cm3 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 D2cm3 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.
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Objective:To compare the difference of preoperative and postoperative plans of navigation-assisted three-dimensional (3D)-printing template combined with CT-guided radioactive 125I seeds implantation for malignant tumors, and verify preliminarily the plan quality of optical navigation-assisted seeds implantation. Methods:From December 2018 to November 2019, a total of 20 patients (10 males, 10 females, median age: 60.5 years) with malignant tumors received navigation-assisted 3D-printing template combined with CT-guided radioactive 125I seeds implantation in Peking University Third Hospital. Eight cases were implanted in the head and neck, 1 case in the chest wall, 9 cases in the pelvis and 2 cases in the paravertebral and/or retroperitoneal region. The median prescription dose was 150 Gy. The data in the preoperative and postoperative plans was compared, including seeds number, needles number, and some dosimetry parameters. Dosimetry parameters including dose delivered to 90% gross tumor volume (GTV) ( D90), percentage of GTV received 100%, 150%, and 200% of the prescribed dose ( V100, V150, V200), minimum peripheral dose (MPD), conformal index (CI), external index (EI), homogeneity index (HI) of target volume, and 2 cm 3 range of spinal cord receiving dose ( D2 cm 3). Paired t test and Wilcoxon signed rank test were used to analyze the data. Results:The needles number of preoperative and postoperative plans was the same (both 12 (9, 19)), and the seeds number of postoperative plan was more than preoperative plan with no significant difference (51(35, 68) vs 49(35, 63); z=1.859, P>0.05). The MPD of postoperative plans was higher than preoperative plans ((80.52±14.89) vs (67.22±20.56) Gy, t=-3.769, P=0.001). There were no significant differences in other dosimetry parameters between the two plans ( t values: -0.533, -0.423, z values: from -0.849 to 1.416, all P>0.05). Postoperative dose quality assessment was excellent in 17 cases (17/20), good in 2 cases (2/20) and middle in 1 case (1/20). Conclusions:The quality of the implantation is good under the guidance of combined mode. The actual target dose after operation can meet the requirements of preoperative planning.
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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 (Dg0),mPD,volume percent of 100％,150％,and 200％ prescribed dose V100、V150、V200 and D2cm3 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,Dg0,mPD,V100,V150,V200 and D2cm3 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.
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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.
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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.
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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.
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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.
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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.
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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.
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Objective To evaluate the efficacy and adverse effects of 125I seeds implantation for pelvic recurrence of cervical cancer (PRCC) after radiotherapy.Methods From July 2005 to October 2015,36 PRCC patients (median 44 years) after radiotherapy in Peking University Third Hospital were enrolled in this retrospective study.All patients underwent 125I seeds implantation under ultrasound or CT guidance.Treatment planning was performed before implantation to estimate the number and activity of 125I seeds.The seed numbers ranged from 10-140 (median:62.5),and the activity ranged from 18.5-29.6 (median:25.9) MBq.Postoperatively,the median dose delivered to 90％ gross tumor volume (D90) was 127.3 Gy.Kaplan-Meier method was used to calculate local progress free survival (LPFS) rate and overall survival (OS) rate,and log rank test and Cox regression were used for univariate and multivariate analyses.Results The median follow-up time was 11.5 months.The local control rate was 88.89％(32/36).The 1-year LPFS rate was 34.9％ and the 1-year OS rate was 52.0％.Thirty-one patients died,of which 22 (70.97％,22/31) died from cancer.Univariate analysis showed that the location of recurrence (x2=5.195),volume of lesion (hazard ratio (HR)=1.012) and D90(HR=0.988) were significantly correlated with LPFS (all P＜0.05).Multivariate analysis showed that the location of the recurrence was significantly related with LPFS (HR =0.215,P＜0.05).The 1-year LPFS rates of pelvic wall recurrence and central recurrence were 41.6％ and 26.7％ (x2 =5.195,P＜0.05),and 1-year OS rates were 54.7％ and 49.5％ (x2 =2.535,P＞0.05),respectively.Vaginal fistula,which may be caused by the treatment,occurred in 1 case.No other sever adverse effects were observed.Conclusions 125I seeds implantation is a safe and effective treatment for PRCC after radiotherapy.With the treatment of 125I seeds implantation,patients with pelvic wall recurrence may achieve better therapeutic effects than those with central recurrence.
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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.
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Objective To compare the preoperative and postoperative dosimetric results of radioactive seed implantation assisted by 3D printing template in the treatment of chest malignant tumor, and to examine the effect this technique on the precision of radioactive seed implantation.Methods A total of 21 patients who received 3D printing template-assisted CT-guided 125I seed implantation for chest tumors in 2016 were included in the study.The prescribed dose of the treatment was 110-180 Gy.Preoperative planning, individual template production, and puncture and seed implantation were performed in all patients, and the postoperative dosimetric results were then compared with the preoperative plan by assessing various dosimetric parameters including D90, MPD, V100, V150, CI, EI, and HI of gross tumor volume (GTV), D2cc of the spinal cord and aorta, and Dmean and V20 of the affected side of the lung.Statistical analysis was performed using the Wilcoxon non-parametric test.Results A total of 21 3D printing templates were designed and produced.The mean GTV volume (preoperative) of all patients was 77.1 cm3, and the mean number of implanted seeds was 68.In addition, the mean D90 of the postoperative GTV was 147.3 Gy.There were slight changes in the dosimetric parameters after treatment (P>0.05).Conclusions 3D printing template allows for accurate positioning and implantation of radioactive seeds during the treatment of chest tumor.Postoperative dosimetric parameters were consistent with those in the preoperative planning, indicating that the 3D printing template provides high precision for the treatment of chest tumor.
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Objective To compare the dosimetric data between preoperative plans and postoperative verification in computed tomography (CT)-guided and 3D-printing non-coplanar templateassisted 125I seed implantation for pelvic tumor,and to explore the feasibility and accuracy of the personalized template designmethod.Methods A total of 51 patients registered from Dec 2015 to Dec 2016 who were applied with 3D-printing guided template assisted radioactive seed implantations in the hospital were included in this study.A prescribed dose of 110-160 Gy was adopted.3D-printing templates were designed and produced for 51 cases.The dosimetric parameters:Dg0,minimum peripheral dose (mPD),V100,V150,V200,conformal index (CI),external index (EI),and homogeneity index (HI) were compared between pre-and post-plans.Results 51 cases' templates were in place well during the operations.Compared with the preoperative planning,the postoperative D90,V100,V150,V200,CI,EI and HI differences had no statistical difference (P ＞ 0.05);mPD is larger than before (t =-2.96,P ＜ 0.05).Conclusions The main dosimetric parameters of postoperative verification were consistent well with the preoperative planning and have good accuracy,which could meet the clinical requirements.
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Objective To investigate the accuracy of 3D-printing non-coplanar template (3D-PNCT) assisted 125I seed implantation with CT guidance in the pelvic recurrent cervical between the preplan and post-plan dosimetric parameters.Methods Nine patients with pelvic recurrent cervical cancer received 125I seed implantation under CT guidance assisted with 3D-PNCT.A pre-plan based brachytherapy treatment planning system (B-TPS) assisted with 3D-PNCT for seed needle depth,direction and angle was designed.The dosimetry parameters including homogeneity index (HI),dose of 90％ target volume (Dg0),mPD,volume percent of 100％,150％ and 200％ prescribed dose V100,V150 and V200 and organ at risk between the pre-plan and post-plan were compared.Results Total seeds number was 675 (median 44,25-114) according to pre-plan,and 669 (median 47,25-113) seeds were implanted actually.138 needles need implant according to preplan,and 132 needles was implanted actually.The median angle deviation was 1.99 ° ± 2.94°(0 °-13 °).There was no significant difference of HI,EI and CI between perand post-plan.The differences of D90,MPD,V100,V150 and V200 between pre-and post-plan were not significant.Conclusions The confidence of pre-plan and post-plan for 3D-PNCT assisted 125I seed implantation in the pelvic recurrent cervical cancer could be accurately performed under CT guidance.
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Objective To investigate the acute side effect of 3D printing individual non-coplanar template for 125I seed implantation in head and neck recurrent/ metastatic carcinoma.Methods Between January 2016 and December 2016,42 patients of local recurrent malignant tumor of head and neck received 3D printing guide plate assist radioactive seeds implantations,and included in the study.The tumor volume ranged from 2.4 to 102.8 cm3 (median 28.6 cm3).The prescribed dose is 110-160 Gy,and the seeds activity were 0.34 to 0.70 mCi (1 Ci =3.7 × 1010 Bq).All patients carried out preoperative planning design,individual guide plate production,seed implantation,postoperative dose assessment,and followup.The side effects of skin,mucous membrane,blood and spinal cord were statistically analyzed.Results All patients were operated successfully.The follow-up time was 4-14 months (median 8.5 months).There were no adverse reactions at grade three or above.Three patients had grade one skin reaction.One patient experienced grade one mucosal reaction,two experienced grade two mucosal reactions.The skin response was correlated with the dose of the skin (x2 =7.067,P =0.032).No hematologic toxicity or radiation myelopathy was observed and no seed displacement was found.Conclusions 3D-printing guide plate can provide good accuracy for positioning and direction.For local recurrent malignant tumor of head and neck,there were no obvious adverse reactions and the operation was simple and the dosage was accurate.
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Objective To establish a model for the calculation of biologically effective dose (BED) and EQD2 (Equivalent dose in 2 Gy fractions) in radioactive seed implantation brachytherapy.Methods The BED formula for EBRT(external beam radiotherapy) and for continuous low dose-rate irradiation established under the L-Q model were introduced.The EDQ2 formula for the continuous low dose-rate irradiation (radioactive seed implantation) was established according to the definition of EQD2 and the formula of BED.The α/β values of common tissues and the Tr 1/2 values reported in the literature were summarized.The EDQ2 formula were further simplified by using the actual values.The empirical formula of EDQ2 for early reaction tissues and late reaction tissues were proposed,named as Wang-Peng empirical formula.EDQ2≈ (10/12) D (Wang-Peng Formula 1) was fit for early response tissue,and EDQ2≈ D/2 (Wang-Peng Formula 2) for late reaction tissues.Further examples on the clinical applications of the proposed formula were given,including primary lung cancer,supraclavicular lymph node metastasis of esophageal cancer and celic lymph node metastasis of cervical carcinoma.Results According to the Wang-Peng empirical formula,the EDQ2 of the late reaction tissue adjacent to the tumor was only about half that of the tumor tissue,so the radioactive seed implantation brachytherapy naturally protected the late reaction tissue by the biological equivalent dose.The actual calculation,showed that the empirical formula of early reaction tissue was more accurate,but the empirical formula of late reaction orgtissue was less inaccurate and could only be roughly estimated.Conclusions The BED calculation formula introduced here and the set of EQD2 calculation formula and Wang-Peng empirical formula established here were theoretically feasible and could be used for the conversion and superposition between the physical dose of radioactive seed implantation brachytherapy and the external irradiation dose.But it should be careful to apply the formula,pay attention to the default conditions,and carefully interpret the calculated results.
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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.