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Objective:To investigate the technical method and clinical efficacy of CT-guided radioactive 125I seed implantation (RISI) assisted by 3D-printed coplanar template(3D-PCT) in the treatment of metastatic tumors of chest wall, and analyze the influence of dosimetric parameters on the treatment efficacy. Methods:A retrospective analysis was conducted for 55 patients with metastatic tumors of chest wall treated with 3D-PCT-assisted 125I radioactive seed implantation in Tengzhou Central People′s Hospital from January 2014 to March 2021.Preoperative plans were made using a brachytherapy treatment planning system, and dosimetric parameters were assessed at 3d after surgery. During regular CT reexaminations after surgery, the local control rate and overall survival (OS) rate were calculated and the pain relief degree and complications were assessed. The Logrank test and Cox regression were used for univariate and multivariate analyses of local control time (LCT). Meanwhile, receiver operating characteristic (ROC) curves were plotted to analyze the critical values of dosimetric parameters and to predict the LCT. Results:The 1-, 2-, and 3-year OS rates ofthe 55 patients were 72.7% (40/55), 21.8% (12/55), and 16.4% (9/55), respectively.The local control rates of 3, 6, 12, and 24 months were 96.4%(53/55), 86.5%(45/52), 85.0%(34/40), and 91.7%(11/12), respectively. There was no statistically significant difference between postoperative and postoperative dosimetric parameters of GTV, particle number, D90, D100, V100, V150, V200, CI, EI, and HI ( P> 0.05). Compared with postoperative V90, the postoperative V90 decreased with a statistically significant difference( P=0.006). As indicated by the univariate Cox regression analysis, the pathological grade, D90, D100, V90, and V200had significant effects on the LCT( P<0.05). Among them, the pathological grade and D90 were independent influencing factors of the LCT, while the other factors showed no statistically significant difference according to the multivariate Cox regression analysis.The LCT of patients with D90≥127 Gy was significantly longer than that of patients with D90<127 Gy (χ 2=16.61, P=0.000). The pain relief rate was 80.8%(21/26) after three months. Five cases suffered from grade Ⅰ-Ⅱ radioactive dermatitis and one case experienced grade Ⅲ radioactive dermatitis. Conclusions:The 3D-PCT-assisted CT-guided 125I radioactive seed implementation can achieve precise and controllable dose and definite efficacy in the treatment of metastatic tumors of chest wall, with few complications.The LCT was remarkably prolonged in the case of D90≥127 Gy, and D90 is an independent influencing factor of the LCT.
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Objective:To compare and analyze the differences of common dose indicators before and after operation of 3D-printing template assisted by CT-guided 125I seed implantation in the treatment of bone metastases to guide clinical application. Methods:A retrospective analysis of 12 lesions in the 10 patients (9 males and 1 female, median age 65 years), who underwent seed implantation surgery for bone metastases in the Tianjin Third Central Hospital from June 2019 to January 2021, was conducted. All the lesions were adopted for 3D-printing template to guide seed implantation and the prescribed dose was 120-140 Gy. The differences of common dose indicators between preoperative treatment plan and postoperative verification plan were compared, including D90 (dose received by 90% of the target volume), D100 (dose received by 100% of the target volume), V90 (the volume percent for tumor target volume receiving 90% of the prescribed dose), V100 (the volume percent for tumor target volume receiving 100% of the prescribed dose), V150 (the volume percent for tumor target volume receiving 150 % of the prescribed dose), as well as the quantity of seeds planned and actually used. The paired t-test was performed to compare and analyze those parameters. Results:There was no statistically significant difference in pre- and postoperative D90, D100, V90, V100, V150 ( P > 0.05). The actual quantity of seeds used after operation was more than that of the preoperative planned quantity and the difference was statistically significant ( t=-2.930, P < 0.05). Conclusions:The clinical use of 3D-printing template assisted by CT-guided 125I seed implantation for bone metastasis should be promoted since the dose is accurate and the requirements of preoperative plan can be achieved.
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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 template-assisted 125I seed implantation for head and neck tumor, aiming to explore the safety, feasibility and accuracy of the individualized template design method.@*Methods@#A total of 42 patients with recurrent/metastatic malignant head and neck tumor admitted to Peking University Third Hospital from January to December 2016 were recruited in this study. A prescribed dose of 110-160Gy was adopted.3D-printing non-coplanar templates were designed for 42 cases. The dosimetric parameters including D90, minimum peripheral dose (mPD), V100, V150, V200, conformal index (CI), external index (EI) and homogeneity index (HI) were statistically compared before and after surgery.@*Results@#All templates were properly implanted intraoperatively. Compared with preoperative planning, postoperative D90, V100, CI, EI and HI did not significantly differ (P=0.490, 0.407, 0.893, 0.143 and 0.079), whereas mPD, V150 and V200 significantly differed (P=0.036, 0.007 and 0.000).@*Conclusion@#After postoperative verification, the main dosimetric parameters have high therapeutic accuracy and properly match with preoperative planning, which can meet clinical requirements.
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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 template-assisted 125I seed implantation for head and neck tumor,aiming to explore the safety,feasibility and accuracy of the individualized template design method.Methods A total of 42 patients with recurrent/metastatic malignant head and neck tumor admitted to Peking University Third Hospital from January to December 2016 were recruited in this study.A prescribed dose of l10-160Gy was adopted.3D-printing non-coplanar templates were designed for 42 cases.The dosimetric parameters including D90,minimum peripheral dose (mPD),V100,V150,V200,conformal index (CI),external index (EI) and homogeneity index (HI) were statistically compared before and after surgery.Results All templates were properly implanted intraoperatively.Compared with preoperative planning,postoperative D90,V100,CI,EI and HI did not significantly differ (P=0.490,0.407,0.893,0.143 and 0.079),whereas mPD,V150 and V200 significantly differed (P=0.036,0.007 and 0.000).Conclusion After postoperative verification,the main dosimetric parameters have high therapeutic accuracy and properly match with preoperative planning,which can meet clinical requirements.
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Objective@#To explore the nursing countermeasures of children with facial rhabdomyosarcoma treated by radioactive seed implantation.@*Methods@#Retrospective analysis was performed on the diagnosis, treatment and nursing process of a child orbital embryonal rhabdomyosarcoma admitted to the department of tumor radiotherapy, Peking University Third Hospital in February 2018.@*Results@#Mild wound swelling and pain occurred after treatment, and no acute complications such as increased intracranial pressure, particle displacement, wound bleeding and infection, or visual acuity change occurred.@*Conclusions@#Disease evaluation and preoperative preparation should be done strictly before the implantation of radioactive particles; changes of the disease should be monitored strictly during the operation to ensure the safety of treatment posture; postoperative complications observation and radiation protection guidance are the basis to ensure the smooth completion of the stage treatment of children.
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Objective To explore the nursing countermeasures of children with facial rhabdomyosarcoma treated by radioactive seed implantation. Methods Retrospective analysis was performed on the diagnosis, treatment and nursing process of a child orbital embryonal rhabdomyosarcoma admitted to the department of tumor radiotherapy, Peking University Third Hospital in February 2018. Results Mild wound swelling and pain occurred after treatment, and no acute complications such as increased intracranial pressure, particle displacement, wound bleeding and infection, or visual acuity change occurred. Conclusions Disease evaluation and preoperative preparation should be done strictly before the implantation of radioactive particles; changes of the disease should be monitored strictly during the operation to ensure the safety of treatment posture; postoperative complications observation and radiation protection guidance are the basis to ensure the smooth completion of the stage treatment of children.
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Objective: To compare the efficacy of radioactive seed localization (RSL) and wire-guided localization (WL) for intraoperative localization of non-palpable breast lesions, and to observe the application value of RSL. Methods Totally 72 women with non-palpable breast lesions who would underwent breast-conserving surgery were enrolled and divided into RSL group (n=34) and WL group (n=38). WL was performed at the same day as surgical excision, while RSL was performed within 5 days before the surgery. The precision rate of location, the rates of tumor-free margin and re-excision, as well as the localization-related complications were compared between the two groups. Results: All lesions were precisely located and completely removed. The tumor-free margin rate and the re-excision rate of RSL was 91.18%(31/34) and 5.88%(2/34), while of WL was 65.79%(25/38) and 28.95%(11/38), respectively. There were significant differences between the two groups (both P<0.01). In WL group, 2 cases occurred wire shifting, 1 case had the vagus nerve response, while no localization-related complication occurred in RLS group. Conclusion: Both RSL and WL can be used for accurate localization and guided-resection of non-palpable breast lesions. Compared with WL, positioning of RSL is not affected by operation time, which has higher tumor-free margin rate and lower re-excision rate.
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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 study the short-term efficacy of computed tomography (CT)-guided iodine-125(125I) radioactive seed implantation in the treatment of hypoxic tumors.Methods Twenty-two patients treated with 125I radioactive seed implantation in our department from 2014 to 2016 were divided into hypovascular tumor group (hypoxic group,n =12) and hypervascular tumor group (non-hypoxic group,n=10) based on the hemodynamics of solid tumor evaluated by color Doppler ultrasound.The enhanced CT images were loaded to the three-dimensional particle implantation planning system for preoperative planning.After 125I radioactive seed implantation,the D90 for target volume was verified to be 106-128 cGy.Treatment outcomes were evaluated according to the World Health Organization criteria at 1-3 months after surgery.Results In all the patients,the overall response rate was 82％ at 3 months after surgery.There were no significant differences in response (complete response + partial response) rates at 1,2,or 3 months after surgery between the hypoxic group and the non-hypoxic group (P=0.840,0.696,0.840).Conclusions In the treatment of solid malignant tumor,125I radioactive seed implantation can overcome the resistance of hypoxic tumor to radiotherapy in vitro and achieve satisfactory short-term efficacy.
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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 investigate the dosimetric effect of same activity and same number of 125I seeds arranged in axial train but with different spacing.Methods A total of 27 film dosimeters were randomly and equally divided into group A,B and C.Each film was irradiated by three 125I seeds (activity of 1.48×107 Bq).The seeds were arranged in line,and their axial spacing was 1 mm,5 mm and 10 mm respectively.Image analysis software was used to draw iso-gray contour curves of 20,25,30 and 40 gray value on the films,and to calculate the areas contained by each curve.Results Multi-sample mean comparison variance analysis showed that the differences in area contained by 20 and 25 iso-gray contour curves were statistically significant between each other among the three groups (P＜0.001).The difference in area contained by 30 iso-gray contour curve between group A and group B was not statistically significant (P＞ 0.05),while the difference in area contained by 30 iso-gray contour curve between group A and group C as well as between group B and group C was statistically significant (P＜0.001).No statistically significant difference in area contained by 40 iso-gray contour curve existed between each other among the three groups (P=0.99).Conclusion Different spacing arrangement of same activity and same number of 125I seeds can directly influence the peripheral dose distribution.In specific dose range,seed-spacing of 1 mm arrangement may obtain better dose distribution than seed-spacing of 5 mm or 10 mm arrangement can do.
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Objective To discuss the necessity and feasibility of intraoperative use of treatment planning system (TPS) to make real-time planning for the treatment of retroperitoneal metastatic carcinoma with CT-guided 125I seed brachytherapy.Methods The clinical data of 20 patients with retroperitoneal lymph node metastases,who received CT-guided 125I seed brachytherapy during the period from January 2013 to December 2015,were retrospectively analyzed.The patients were divided into group A (n=10) and group B (n=10).The intraoperative TPS was employed to formulate the real-time planning for the patients of group A,while real-time planning was not adopted for the patients of group B.The quality verification of preoperative planning and postoperative effect was conducted for the patients of both groups.Comparing the preoperative and postoperative absorbed dose,the minimum absorbed dose (D90) error percentage of 90％ target volume,the error percentage of the covered volume by 90％ prescription dose to the target volume (V90),the error percentage of the covered volume by 100％ prescription dose to the target volume (V100),and the error percentage of the covered volume by 150％ prescription dose to the target volume (V150) were calculated in all patients of both groups,and the results were statistically analyzed.Results The mean error percentage of D90,V90,V100,V150 in group A were (-1.30±6.80) Gy,(-0.60±2.10)％,(-0.47±2.70)％ and (89.60±282.00)％ respectively,which in group B were (-9.33±46) Gy,(11.50±13.7)％,(-13.40±15.90)％ and (10.37±2.00)％ respectively.The differences in the error percentage of D90,V90 and V100 between group A and group B were statistically significant (P＜0.05 in all),while no statistically significant difference in the error percentage of V150 existed between group A and group B (P＞0.05).Conclusion The use of intraoperative TPS real-time planning can significantly improve the consistency of target region dose before and after seed implantation and make the dose distribution more reasonable,which is of great value for the standardization of CT-guided 125I seed brachytherapy of retroperitoneal lymph node metastases.
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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 investigate the feasibility of reducing CT scanning dose in the process of 125I radioactive seed implantation.Methods GEMS phantom and 062 M phantom were scanned using GE Lightspeed RT large hole CT with 120 kV,100 kV and 80 kV separately,and 150-10 mA (20 mA decreased progressively).The scanning dose,CT value and noise of the region of interest were recorded and the image quality was evaluated.Image signal-to-noise ratio (SNR) and contrast to noise ratio (CNR) values were calculated.Results With the decreasing of tube voltage and current,the SNR values were reduced accorgingly.The values had significant difference with those of standard images except the images acquired with 120 kV,150-70 mA and 100 kV,150-90 mA (t =-9.294-3.717,P ＜0.05).With the decreasing of the tube voltage and current,the CNR decreased significantly.The image quality was too low to evaluate while CNR lower than 2.The high contrast resolution of the CT images were not affected obviously with the tube voltage and current lowering.Conclusions In the process of 125I radioactive seed implantation,it is feasible to choose lower tube voltage and tube current(100 kV,70 mA) to scan the same area repeatedly except for the first scan with standard chest scanning parameters.The patient radiation dose has fallen dramatically.
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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 compare the dose distribution of postoperative plans with preoperative plans for 3D printing coplanar template assisted radioactive seed implantation,and to explore the accuracy of the technique in seed implantation.Methods From November 2015 to December 2016 a total of 32 patients were selected and underwent 3D printing coplanar template assisted radioactive seed implantation in Tengzhou Central People's Hospital of Shandong province.There were 36 implanted lesions,including l0 in the lungs,5 in neck lymphs,3 in pelvic cavities,3 in vertebral body,2 in pancreas,2 in abdominal lymph nodes,2 in portal veins,and 9 in the other parts.All patients were given preoperative planning and guided by the coplanar templates.Compared with the preoperative plan,all levels needles inserted at the same time.According to preoperative planning the implantation surgery was completed accurately.The postoperative dosimetry was evaluated.The preoperative and postoperative dosimetry parameters were compared,including Dg0,D100,V90,V100.V150,V200 and conformal index (CI),external index (EI),and homogeneity index(HI).The paired t test was used to perform the statistical analysis.Result There was no significant differences in Dg0,D100,V90,V100,V150,V200,CI,EI and HI between before and after operation(P ＞ 0.05).Conclusions The dose parameters in postplan showed no difference compared with preplan in this study.For fixed and moving organ tumors,3D printing coplanar template assisted radioactive seed implantation has good therapeutic accuracy,and may be a standardized surgicalmethod for seed implantation in the future.
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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 evaluate the efficacy of computed tomography ( CT ) image?guided 125 I radioactive seed implantation for locally recurrent rectal cancer ( LRRC ) , and to analyze the relationship between the dosimetry and prognosis. Methods A retrospective analysis was performed on the clinical data of 36 patients with LRRC who received CT image?guided 125 I seed implantation in our hospital from 2003 to 2011. Dosimetric verification was performed using CT scan immediately after 125 I seed implantation. The D90 , D100 , V100 , and V150 values were evaluated. In all the patients, the median activity of seeds was 0?7 mCi (0?4?0?8 mCi) and the median number of implanted seeds was 74(33?137). The local control (LC) and overall survival ( OS ) rates were calculated using the Kaplan?Meier method. The log?rank test and Cox regression model were used for the univariate and multivariate analyses, respectively. Results The median OS time was 16?2 months ( 95% CI= 13?5?18?9 months ) . The median LC time was 10?0 months (95% CI=6?2?13?8 months). The D90 and V100 values were (118.6±25?1) Gy and (90.0±0?3)%, respectively. The univariate analysis suggested that D90 was correlated with the LC time ( P=0?048) and V100 was correlated with the OS time ( P=0?035) . The multivariate analysis showed that a V100 value higher than 90% was a prognostic factor of OS (P=0?044). Conclusions In the treatment of LRRC using CT image?guided 125 I radioactive seed implantation, a D90 value larger than 140 Gy and a V100 value higher than 90% in the postoperative verification plan help improve the LC and OS rates. The D90 and V100 values in the postoperative verification plan may predict treatment outcomes in patients.
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Objective To compare the dose distribution of postoperative plans with preoperative plans for 3D printing guide template assist radioactive seeds implantations,and explore the accuracy of treatment at dosimetry level.Methods A total of fourteen patients registered from Dec 2015 to Mar 2016 who were applied with 3D printing guide template assisted radioactive seed implantations in the hospital were included in this study.The preoperative planning design and 3D printing template production were performed for all patients.The dose related parameters including D90％,minimum peripheral dose (MPD),V100％,V150％,V200％,conformal index (CI),external index (EI),and homogeneity index (HI) were compared between pre-and post-operation.The paired t-test was used to perform the statistical analysis.Results A total of fourteen 3D printing individual templates were produced which included 16 treatment areas.Compared with preoperative plans,the mean value of V100％,Dg0％ and V150％ decreased while the mean value of V200％ and MPD increased in postoperative plans.However,there was no significant difference between the two groups except for V100％ (t =2.451,P ＜0.05).The differences of CI,EI,HI between two groups were not statistically significant (P ＞ 0.05).Conclusions The validation of actual dose distribution in postoperation assistied by 3D printing template in seed implantation shows that most of parameters could meet the expectation of preoperative plans,which indicates the improvement in accuracy for this new type of treatment.