Three-Dimensional-Printed Template-Guided Radioactive Seed Brachytherapy via a Submental Approach for Recurrent Base of Tongue and Floor of Mouth Cancer.

Background: This study assessed clinical outcomes of three-dimensional-printed template (3DPT)-guided radioactive seed brachytherapy (RSBT) via a submental approach for recurrent base of tongue and floor of mouth cancer. Methods: Thirty-one patients with recurrent lingual and floor of mouth squamous cell carcinoma after surgery and radiotherapy were treated with 3DPT-guided RSBT from 2015 to 2022. Seeds were implanted through a submental approach guided by 3DPTs. Local control (LC), overall survival (OS), disease control (DC) and quality of life (QOL) were evaluated. Results: The median follow-up was 13.7 months. The 1-, 3- and 5-year LC rates were 66.1%, 66.1%, and 55.1% respectively. The 1-, 3- and 5-year OS rates were 63.4%, 33.4%, and 8.3%. The 1-, 3- and 5-year DC rates were 37.8%, 26.5%, and 21.2%. Univariate analysis showed tumor size significantly affected LC (P = 0.031). The presence of extraterritorial lesions affected DC and OS on multivariate analysis (P < 0.01). QOL improved significantly in domains of pain, swallowing, chewing, taste, and emotion after treatment compared to baseline. Four patients (13%) developed necrosis and osteoradionecrosis. Conclusions: 3DPT-guided submental RSBT provided favorable LC and QOL for recurrent tongue/floor of mouth cancer with minimal toxicity; moreover, severe toxicity should be noted.

Utility of spectral CT with orthopedic metal artifact reduction algorithms for 125I seeds implantation in mediastinal and hepatic tumors.

Background: Virtual monochromatic image (VMI) combined with orthopedic metal artifact reduction algorithms (VMI + O-MAR) can effectively reduce artifacts caused by metal implants of different types. Nevertheless, so far, no study has systematically evaluated the efficacy of VMI + O-MAR in reducing various types of metal artifacts induced by 125I seeds. The aim of this study was to assess the effectiveness of combining spectral computed tomography (CT) images with O-MAR in reducing metal artifacts and improving the image quality affected by artifacts in patients after 125I radioactive seeds implantation (RSI). Methods: A total of 45 patients who underwent dual-layer detector spectral CT (DLCT; IQon, Philips Healthcare) scanning of mediastinal and hepatic tumors after 125I RSI were retrospectively included. Spectral data were reconstructed into conventional image (CI), VMI, CI combined with O-MAR (CI + O-MAR), and VMI + O-MAR to evaluate the de-artifact effect and image quality improvement. Objective indicators included signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and artifact index (AI) of lesions affected by artifacts. Subjective indicators included assessment of overcorrected artifacts and new artifacts, different morphology of artifacts, and overall image quality. Results: In artifact-affected lesion areas, SNR and CNR in the CI/VMI + O-MAR groups were better than those in CI groups (all P values <0.05). The AI showed a downward trend as VMI keV increased (all P values <0.001). The AI values of the CI/VMI (50-150 keV) group were all higher than the groups of CI/VMI + O-MAR (50-150 keV) (P<0.001). Overcorrection artifacts and new artifacts were concentrated in the VMI50/70 keV groups. In the evaluation of artifact morphology, as the VMI keV increased, the number of near-field banding artifacts in hyperdense artifacts gradually decreased, whereas the number of minimal or no artifacts increased, and the total number of hyperdense artifacts were decreased. The diagnostic and image quality scores of hyperdense artifacts were higher than those of hypodense artifacts as VMI keV increased. Conclusions: High VMI level combined with O-MAR substantially improve objective and subjective image quality, lesion display ability, and diagnostic confidence of CT follow-up after 125I RSI, especially at the VMI + O-MAR 150 keV level.

Interstitial implantation of radioactive seeds for pancreatic cancer pain management / 中华内分泌外科杂志

Objective:To assess the effectiveness and characteristics of intratumoral radioactive seed implantation in pancreatic cancer pain management.Methods:Clinical data of 160 patients with pancreatic cancer receiving radioactive seed implantation were retrospectively analyzed. Both pre- and postoperative pain intensities were evaluated using the visual analog scale (VAS) .Results:About 71.88% (115) of 160 patients experienced abdominal or low back pain. Postoperative pain in 104 patients was relieved at various degrees after radioactive seed implantation with an analgesic efficacy of 90.43% (the efficacy for abdominal and low back pain relief was 86.52% and 96.34%, respectively). The between-group difference was statistically significant. Pain relief was observed 1-7 days postoperatively, and the maximal degree of pain relief was achieved 2-14 days after treatment initiation.Conclusion:Intratumoral implantation of radioactive seeds was microinvasive, quick-acting, and effective in pancreatic cancer pain management.

Spinal brachytherapy.

Brachytherapy remains an underrecognized and underutilized radiation therapy modality for the treatment of spinal tumors. This article summarizes the existing body of medical literature on the usage, indications, techniques, and outcomes of brachytherapy for the treatment of spine tumors. The disease pathology most commonly treated with brachytherapy is metastatic spine cancer, rather than primary bone tumors of the spine. Brachytherapy can be used alone, as percutaneous needle injections; however, it is more often used in conjunction with open surgery or cement vertebral body augmentation. Although the data are still relatively sparse, studies show consistent benefit from brachytherapy in terms of improvements in pain, function, local recurrence rate, and overall survival. Brachytherapy is also associated with a favorable complication profile.

A machine-learning approach based on 409 treatments to predict optimal number of iodine-125 seeds in low-dose-rate prostate brachytherapy.

PURPOSE: Low-dose-rate brachytherapy is a key treatment for low-risk or favorable intermediate-risk prostate cancer. The number of radioactive seeds inserted during the procedure depends on prostate volume, and is not easy to predict without pre-planning. Consequently, a large number of unused seeds may be left after treatment. The objective of the present study was to predict the exact number of seeds for future patients using machine learning and a database of 409 treatments. MATERIAL AND METHODS: Database consisted of 18 dosimetric and efficiency parameters for each of 409 cases. Nine predictive algorithms based on machine-learning were compared in this database, which was divided into training group (80%) and test group (20%). Ten-fold cross-validation was applied to obtain robust statistics. The best algorithm was then used to build an abacus able to predict number of implanted seeds from expected prostate volume only. As an evaluation, the abacus was also applied on an independent series of 38 consecutive patients. RESULTS: The best coefficients of determination R 2 were given by support vector regression, with values attaining 0.928, 0.948, and 0.968 for training set, test set, and whole set, respectively. In terms of predicted seeds in test group, mean square error, median absolute error, mean absolute error, and maximum error were 2.55, 0.92, 1.21, and 7.29, respectively. The use of obtained abacus in 38 additional patients resulted in saving of 493 seeds (393 vs. 886 remaining seeds). CONCLUSIONS: Machine-learning-based abacus proposed in this study aims at estimating the necessary number of seeds for future patients according to past experience. This new abacus, based on 409 treatments and successfully tested in 38 new patients, is a good alternative to non-specific recommendations.

Advantages of interstitial radioactive seed implantation for the treatment of Stage III pancreatic cancer.

OBJECTIVE: The objective of the study was to identify the advantages of interstitial radioactive seed implantation for the treatment of Stage III pancreatic cancer. MATERIALS AND METHODS: Clinical data of 160 patients with pancreatic cancer implanted with radioactive seeds were retrospectively analyzed. Patients were grouped according to tumor size, lymph node metastasis, and tumor invasion to important blood vessels, and survival time statistics were obtained. RESULTS: The mean postoperative survival time (months) was 24.80 for Stage I, 12.89 for Stage II, 13.51 for Stage III, and 7.49 for Stage IV patients, and the difference between Stage II and Stage III patients was not statistically significant. The efficacy of radioactive seed implantation therapy for pancreatic cancer was strongly associated with tumor size and number of lymph node metastases but not significantly associated with tumor invasion to blood vessels. CONCLUSIONS: Radioactive seed implantation obviously advantageous for the treatment of Stage III pancreatic cancer.

Stent with radioactive seeds strand insertion for malignant hilar biliary obstruction.

PURPOSE: This study aimed to assess clinical efficacy and long-term patient outcomes in individuals with malignant hilar biliary obstruction (MHBO) that had been treated via insertion of a stent with a radioactive seed strand (RSS). MATERIAL AND METHODS: A total of 84 MHBO patients were treated via either normal stent insertion (n = 48) or stent with RSS insertion (n = 36) from January 2015 to December 2018. RESULTS: The technical success rates of normal stent insertion and stent with RSS insertion were 93.8% (45/48) and 97.2% (35/36), respectively (p = .632), with clinical success rates of 93.3% (42/45) and 100% (35/35), respectively (p = .252). In these two patient groups, 11 and seven patients, respectively, suffered from stent dysfunction (p = .637). In the normal and RSS groups, median stent patency was 165 and 225 days, respectively (p < .001). All patients in the present study died due to tumor progression, with median survival times of 188 and 250 days in the normal and RSS stent groups, respectively (p < .001). CONCLUSION: Relative to normal stent insertion, combined stent with RSS insertion can effectively prolong both stent patency and patient survival in patients with MHBO.

Radioactive I-125 seed implantation in treatment of TACE-refractory hepatocellular carcinoma / 中华肝胆外科杂志

Objective:To study the use of radioactive I-125 seed implantation in the treatment of transarterial chemoembolization (TACE)-refractory hepatocellular carcinoma (HCC).Methods:A retrospective study was conducted on 70 patients with HCC who were initially treated with TACE between July 1, 2016 and August 31, 2019 at the Second Affiliated Hospital of Guangzhou Medical University. After these patients were found to be refractory to TACE, 29 patients were converted to radioactive I-125 seed implantation (the 125I seed group), and 41 patients were continued with TACE (the TACE group). The objective response rate, progression-free survival (PFS), overall survival (OS), total overall survival (TOS) of the two groups were compared. Results:There were 59 males and 11 females, aged (60.5±11.9 ) years in this study. At 1, 3, 6 months after treatment, the objective response rates of the 125I seed group were 20.7%, 40.7%, 34.6%, respectively, which were significantly higher than that of the TACE group of 2.6%, 3.3%, 5.0%, respectively. The PFS, OS, TOS in the 125I seed group were 7.6, 21.1, 32.1 months, respectively, which were significantly better when compared with the TACE group (3.5, 8.5, 14.8 months, respectively, all P<0.05). There was no significant difference in the embolization syndrome between the two groups [93.1%(27/29) vs 100.0%(41/41), P>0.05]. Child-Pugh B grading ( HR=0.311, 95% CI: 0.160-0.603, P=0.005) and TACE ( HR=0.308, 95% CI: 0.159-0.597, P=0.002) were independent risk prognostic factors for survival. Conclusion:This study showed better treatment efficacy and safety using radioactive I-125 seed implantation in TACE-refractory HCC and this treatment significantly improved survival of patients when compared with TACE alone.

Target delineation and dosimetry analysis of 125I interstitial brachytherapy for recurrent adenoid cystic carcinoma in the parotid gland / 中华放射医学与防护杂志

Objective:To analyze the target design and dosimetric parameters of patients with recurrent adenoid cystic carcinoma (ACC) in the parotid gland who were treated with 125I interstitial brachytherapy alone. Methods:A retrospective analysis was conducted for 25 patients with recurrent adenoid cystic carcinoma in parotid gland who were histopathologically diagnosed between January 2015 and October 2019. These patients were treated with 125I interstitial brachytherapy alone, with prescribed doses of 100-120 Gy. The target volume was designed according to the pathological characteristics of ACC and recurrence sites. The pre- and post-operation dosimetric parameters (i.e., local control rates) were calculated using the treatment planning system. Results:In this study, the local recurrence sites included the superficial lobe (10/25) and deep lobe (7/25) of the parotid gland primarily and the skull base region (four patients) and mastoid posterior region (four patients) secondarily. The number of 125I seeds ranged from 16 to 111, with a median number of 59. The activity of radioactive particles was 18.5-25.9 MBq. The 3- and 5-year local control rates were 81.5% and 61.5%, respectively. No significant differences were found between pre- and post-operative dosimetric parameters such as D90, V100, and V150. There was no significant difference in local control rates among the four different recurrence sites. Conclusions:125I interstitial brachytherapy is proven to be an effective approach in the treatment of recurrent adenoid cystic carcinoma in the parotid gland. Satisfying local control rates can be achieved through target delineation performed according to recurrence sites and perineural invasion characteristics of ACC.

Significance of 125I radioactive seed implantation on growth differentiation factor and programmed death receptor-1 during treatment of oral cancer.

BACKGROUND: Oral cancer (OC) is the most common malignant tumor in the oral cavity, and is mainly seen in middle-aged and elderly men. At present, OC is mainly treated clinically by surgery or combined with radiotherapy and chemotherapy; but recently, more and more studies have shown that the stress trauma caused by surgery and the side effects of radiotherapy and chemotherapy seriously affect the prognosis of patients. AIM: To determine the significance of 125I radioactive seed implantation on growth differentiation factor 11 (GDF11) and programmed death receptor-1 (PD-1) during treatment of OC. METHODS: A total of 184 OC patients admitted to The Second Affiliated Hospital of Jiamusi University from May 2015 to May 2017 were selected as the research subjects for prospective analysis. Of these patients, 89 who received 125I radioactive seed implantation therapy were regarded as the research group (RG) and 95 patients who received surgical treatment were regarded as the control group (CG). The clinical efficacy, incidence of adverse reactions and changes in GDF11 and PD-1 before treatment (T0), 2 wk after treatment (T1), 4 wk after treatment (T2) and 6 wk after treatment (T3) were compared between the two groups. RESULTS: The efficacy and recurrence rate in the RG were better than those in the CG (P < 0.05), while the incidence of adverse reactions and survival rate were not different. There was no difference in GDF11 and PD-1 between the two groups at T0 and T1, but these factors were lower in the RG than in the CG at T2 and T3 (P < 0.05). Using receiver operating characteristic (ROC) curve analysis, GDF11 and PD-1 had good predictive value for efficacy and recurrence (P < 0.001). CONCLUSION: 125I radioactive seed implantation has clinical efficacy and can reduce the recurrence rate in patients with OC. This therapy has marked potential in clinical application. The detection of GDF11 and PD-1 in patients during treatment showed good predictive value for treatment efficacy and recurrence in OC patients, and may be potential targets for future OC treatment.

Clinical effectiveness of combined interventional therapy as a salvage modality for unresectable pancreatic carcinoma.

Although different treatment methods have been introduced to treat advanced pancreatic carcinoma, the median overall survival rate remains unsatisfactory. Theoretically, combining different treatment methods should work in synergy to enhance locoregional disease control and improve survival. Therefore, the aim of the present retrospective study was to analyze the effectiveness of combined interventional therapy compared with trans-arterial chemoembolization (TACE) or chemotherapy alone for the treatment of unresectable pancreatic carcinoma. A total of 266 patients who were undergoing treatment for unresectable pancreatic carcinoma between July 2012 and November 2015 were included in the current study. The tumor responses and 3-year overall survival rates of patients treated with combined interventional therapy (TACE combined with iodine-125 seed implantation and/or radiofrequency ablation; CIT group; n=84) were compared with those of patients treated with TACE alone (TACE group; n=59), as well as patients treated with systemic chemotherapy alone (control group; n=123). Patients in the CIT group exhibited significantly improved tumor responses compared with patients in the TACE group (51.89 vs. 30.61%; P=0.028) or control group (51.89 vs. 17.20%; P<0.001). The 3-year overall survival rate of the CIT group was also significantly higher compared with that of the TACE and control groups (P=0.0116 and P=0.0001, respectively). Furthermore, the CIT group exhibited a significantly higher overall survival rate for patients with unresectable metastatic pancreatic cancer compared with the TACE and control groups (P=0.0088 and P<0.0001, respectively), which suggests that a combination of different interventional techniques increases the survival of patients with unresectable pancreatic cancer. No life-threatening complications were observed in any treatment group. In conclusion, combined interventional therapy exhibits a good efficacy and an improved survival rate for unresectable pancreatic cancer compared with TACE alone.

DTI and pathological changes in a rabbit model of radiation injury to the spinal cord after 125I radioactive seed implantation.

Excessive radiation exposure may lead to edema of the spinal cord and deterioration of the nervous system. Magnetic resonance imaging can be used to judge and assess the extent of edema and to evaluate pathological changes and thus may be used for the evaluation of spinal cord injuries caused by radiation therapy. Radioactive 125I seeds to irradiate 90% of the spinal cord tissue at doses of 40-100 Gy (D90) were implanted in rabbits at T10 to induce radiation injury, and we evaluated their safety for use in the spinal cord. Diffusion tensor imaging showed that with increased D90, the apparent diffusion coefficient and fractional anisotropy values were increased. Moreover, pathological damage of neurons and microvessels in the gray matter and white matter was aggravated. At 2 months after implantation, obvious pathological injury was visible in the spinal cords of each group. Magnetic resonance diffusion tensor imaging revealed the radiation injury to the spinal cord, and we quantified the degree of spinal cord injury through apparent diffusion coefficient and fractional anisotropy.

Efficacy of 125I Versus Non-125I Combined with Transcatheter Arterial Chemoembolization for the Treatment of Unresectable Hepatocellular Carcinoma with Obstructive Jaundice.

PURPOSE: To compare the therapeutic effects of 125I versus non-125I combined with transcatheter arterial chemoembolization (TACE) for the treatment of unresectable hepatocellular carcinoma (HCC) with obstructive jaundice. METHODS: A retrospective analysis was conducted using the records of 54 consecutive patients who were initially diagnosed with HCC with obstructive jaundice between May 2009 and July 2016. Twenty-one cases (group A) were treated with percutaneous transhepatic biliary drainage (PTBD) followed by 125I radioactive seed strip implantation through the PTBD tube. After the total serum bilirubin level was reduced to normal and the liver function recovered to Child-Pugh class A or early B, TACE was conducted. In 33 cases (group B) PTBD was performed in combination with TACE without applying the 125I radioactive seeds. The duration of biliary patency and survival were analyzed. RESULTS: The technical success rate in both groups was 100%. The median biliary patency time was 6.000 ± 0.315 months (95% CI 5.382-6.618 months) in group A and 4.000 ± 0.572 months (95% CI 2.879-5.121 months) in group B; the two groups were significantly different (P = 0.001). The median survival was 11.000 ± 0.864 months (95% CI 9.306-12.694 months) in group A and 9.000 ± 0.528 months (95% CI 7.965-10.035 months) in group B; the two groups were significantly different (P = 0.022). CONCLUSIONS: The combination of 125I with TACE was more effective than TACE without the radioactive seeds for treating patients with unresectable HCC with obstructive jaundice. Future prospective trials with larger samples will be required to validate these results.

Operation procedure for 125I seed brachytherapy in malignant solid tumor of the abdomen / 中华内分泌外科杂志

The apphcation of radioactive seeds implantation in treatment of malignant solid tumor of the abdomen has been 18 years in China.The teatment is applied by more and more hospitals,however,the operation procedure is not the same in each hospital,which affected the therapeutic effect of radioactive seeds implantation,and means more safety risks.This paper summarizes the operation procedures of radioactive seeds implantation in treatment of malignant solid tumor of the abdomen,and minimizes the loopholes in clinical operation,in order to improve the therapeutic effect and reduce the safety risks.

Study on the influence of 125I seed implantation brachytherapy on QOL of patients with salivary gland malignant tumor / 中华放射医学与防护杂志

Objective To evaluate the influence of 125I seed implantation brachytherapy on QOL of patients with salivary gland malignant tumor which couldn't be treated by conventional surgery and its influence factors. Methods 23 patients with malignant salivary gland cancer which couldn't be treated by conventional surgery were selected from Peking University School of Stomatology from 2013 to 2017. The patients were treated by 125I seed implantation brachytherapy. EORTC QLQ-C30 ( V3. 0 ) as well as QLQ-H&N35 QOL scale ( Chinese version) were used for the assessment of post-treatment QOL. Results The survival rate of one year and three years after treatment in 23 patients was 100％ and 67％, respectively. The score of the quality of life before and after treatment was 201. 48 and 199. 48, respectively. The difference was not significant after the test ( P>0. 05 ) . The level of total QOL and function score were relatively high. Among the influence factors, location of tumor significantly influenced QOL( F=9. 127,P<0. 05). Other factors still needed research based on larger sample. Conclusions 125I seed implantaion brachytherapy can better protect the head and neck function and maintain the quality of life of patients with salivary gland malignant tumor.

An endoscopic ultrasonography-guided interstitial brachytherapy based special treatment-planning system for unresectable pancreatic cancer.

EUS-guided interstitial brachytherapy is promising in the treatment of unresectable malignant carcinoma adjacent to the digestive tract. The feasible treatment plan is not established. Thus, our study aimed to develop a novel treatment plan and evaluate the feasibility in patients with unresectable pancreatic cancer. A total of 42 patients with unresectable pancreatic cancer (stage III: n = 18; stage IV: n = 24) were retrospectively included. A special treatment-planning system (TPS) for EUS was designed and evaluated by comparing with the traditional TPS. The patients underwent EUS-guided interstitial brachytherapy based on the new software. In the test model, there was no obvious difference of irradiation doses calculated by the two softwares (EUS TPS vs. traditional TPS) (P > 0.05). Under the support of EUS TPS, a novel treatment plan for EUS-guided interstitial brachytherapy was successfully established, which contained seven principles. All patients tolerated the treatment well without any serious complications. In 15 patients (stage III) whose minimal peripheral dose was larger than 90 Gy, partial remission rate was 80% (12/15). Twelve patients (12/18) in stage III were alive for over 12 months with a median peripheral dose of 107.5 Gy. The expected median survival time of the 42 patients was 9.0 months (95%CI 7.6-10.4 months). The results demonstrated that the new EUS TPS will play an important role in EUS-guided interstitial brachytherapy in patients with unresectable pancreatic malignant cancer.

Dosimetry verification of radioactive seed implantation for malignant tumors assisted by 3D printing individual templates and CT guidance.

OBJECTIVE: We compared the dose distributions of postoperative plans with preoperative plans for 3D printing template-assisted radioactive seed implantations. METHODS: A total of 14 patients with malignant tumors enrolled in the study. The dose parameters included D90, minimum peripheral dose, V100, V150, and V200. The statistical method was the paired t-test. RESULTS: There was no significant difference in P values between the two groups for all parameters except for V100. CONCLUSIONS: The 3D printing guide template can provide good accuracy for radioactive seed implantation.

Pulse sequence considerations for simulation and postimplant dosimetry of prostate brachytherapy.

PURPOSE: The purpose of this work is to present a brief review of MRI physics principles pertinent to prostate brachytherapy, and a summary of our experience in optimizing protocols for prostate brachytherapy applications. METHODS AND MATERIALS: We summarized essential MR imaging characteristics and their interplays that need to be considered for prostate brachytherapy applications. These include spatial resolution, signal-to-noise ratio, image contrast, artifacts, geometric distortion, specific absorption rate, and total scan time. We further described the optimization of the protocols for three pulse sequences: three-dimensional (3D) fast-spoiled gradient echo sequence for T1-weighted imaging, 3D fast-spin echo sequence for T2-weighted imaging, and 3D fast imaging in steady-state precession sequence for combined T1 and T2-weighed imaging. The utilization of an endorectal coil was also described. RESULTS: Using the optimized protocols, we acquired high-quality images of the entire prostate within 3-5 minutes for each sequence. These images display the desired image contrasts and a spatial resolution that is equal to or better than 0.59 mm × 0.73 mm × 1.2 mm. While 3D fast-spoiled gradient echo sequence and 3D fast-spin echo sequence depict radioactive seed markers and anatomic structures separately, 3D fast imaging in steady-state precession sequence demonstrates great promise for imaging both seed markers and prostate anatomy simultaneously in a single acquisition. CONCLUSIONS: We have optimized current MRI protocols and demonstrated that the anatomic structures and positive contrast radioactive seed markers for prostate post-implant dosimetry can be adequately imaged either separately or simultaneously using different pulse sequences within a total scan time of 3-5 minutes each.

Application of 3D-printing in accurate seed implantation therapy / 中华放射医学与防护杂志

Brachytherapy is an important modality for cancer treatment,with advantages of local high doses and little damages to surrounding normal tissues,including high and low dose rate.In the low dose rate brachytherapy,the seeds are implanted into the locations of tumor by way of puncture to kill the tumor cells.The low dose rate brachytherapy for prostate cancer has received the same outcome with surgery and external radiation therapy.3D-printing template was produced by computer program based on image scan information and the needle tract,based on definition of the target prescription dose and 3D-printing template assisted CT guidance for needles puncture and seed implantation.Seed implantation has become the standard procedure in treatment for head and neck,thoracic,abdomen and pelvic cancers according to pre-plan,real-time optimization and post-dese evaluation,which is a symbol of new era for seed implantation.

Dosimetry analysis of radioactive seed implantation supported by coplanar template for lung cancer patients with mediastinal lymph node metastases 4R / 中华放射医学与防护杂志

Objective To compare the planned radiation dose and the actual dose received after 125I radioactive seeds implantation supported by coplanar template (CPT) in lung cancer patients with mediastinal node metastases 4R,and to evaluate the clinical efficacy.Methods Totally 32 patients with lung cancer with mediastinal lymph node metastases 4R who had been diagnosed via cellular pathology studies were selected from January 2008 to December 2014.The mediastinal lymph node metastases were treated by CPT-assisted 125I radioactive seed implantation.Digital imaging and communications in medicine (DICOM) data were acquired by chest CT scan before implantation,brachytherapy radiation treatment planning system (BTPS) was introduced to carry out the plan,and the prescribed dose(PD) was 120 Gy.CPT was used to control the precision of needle penetration and implantation of radioactive seeds.Computer tomography (CT) was used to ensure the correct position of needles and radioactive seeds.Dose evaluation was performed immediately after implantation and was compared with planned dose using paired t-test.The 6-months postoperative chest CT was conducted to evaluate treatment efficacy according to response evaluation criteria in solid tumors(RECIST Version 1.1).Results All patients went through implantation procedure successfully.Dose evaluation after implantation was as followed.The average dose received (231.9 ±29.6)Gy,the dose received by 90％ of the target(D90) (150.8 ± 16.6) Gy,the dose received by 100％ of the target(D100) (100.4 ± 12.6)Gy,the volume of 100％PD covering the target(V100)(94.1 ± 2.6) ％,the volume of 200％ PD covering the target(V200) (33.0 ± 5.7) ％,the conformal index (CI) 0.75 ±0.06,the external index(EI) (22.7 ± 5.8)％,the average dose received by the superior vena cava (19.3 ± 7.2)Gy,and the average dose received by aorta (12.1 ± 5.1)Gy.Efficacy was followed for 6 months after implantation and the effective rate was 84.37％.There was no serious complications (such as radioactive lung injury,major vascular injury,bleeding,and et al.) occurred in follow-up period.Conclusions CPT assisted CT guided 125I radioactive seed imnplantation in treating mediastinal node metastases 4R can achieve preoperative BTPS,minimize major vascular or organ injury.It is an accurate,effective and safe treatment approach and may be of great value to standardize the procedure of radioactive seed implantation in mediastinal metastases.