DTI and pathological changes in a rabbit model of radiation injury to the spinal cord after ^(125)I 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.

Dosimetry for ^(125) I radioactive seed implantation therapy for hepatocellular carcinoma

Hepatocellular carcinoma （HCC） is an aggressive malignancy. Early lesions respond well to hepatic resection or liver transplantation. However, only a few of HCC patients are suitable for surgical intervention. External beam radiation and chemotherapy is poorly efficacious. In the last 20 years, HCCs belonging to the radiosensitive tumor group has been confirmed. Along with the development of new radiotherapy technology and facilities, the research about brachytherapy（especially ^125I seed implantation therapy） has provoked more interests in the world. Radioactive seed implantation therapy is a form of interstitial brachytherapy, with the property of local ＂conformal radiotherapy＂ and the advantages of minimal invasion, convenience, high performance, and minimal adverse effects. It is a promising therapy for HCC, however the dosimetry hasn＇ t yet been identified and lacks verification in prospective research. This report aims to further explore the best prescription dose and radioactivity for ^125I interstitial implantation brachytherapy for HCC.

Relationship between miR-7-5p expression and ^(125)I seed implantation efficacy in pancreatic cancer and functional analysis of target genes

Objective The aim of this study was to investigate the relationship between miR-7-5p expression and intertissue-^(125)I irradiation sensitivity in pancreatic cancer tissues and to analyze the function of target genes.Methods Thirty-seven patients with unresectable pancreatic ductal adenocarcinoma(PDAC)treated with radioactive ^(125)I seed implantation were enrolled.RT-PCR was used to detect the expression level of miR-7-5p in cancer tissues and analyze the relationship between miR-7-5p expression and ^(125)I radiation sensitivity.Bioinformatic software and online tools were used to predict the miR-7-5p target genes and analyze their functional annotation and pathway enrichment.Results Radioactive ^(125)I seed implantation was followed up for 2 months.The objective response rate of the miR-7-5p high expression group was 65.0%(13/20),whereas the objective response rate of the miR-7-5p low expression group was 5.88%(1/17),and the difference between the two groups was statistically significant(χ^(2)=13.654,P<0.001).A total of 187 target genes were predicted using three databases.GO functional annotation showed that target genes were mainly involved in cellular response to insulin stimulus,regulation of gene expression by genetic imprinting,cytosol,peptidyl-serine phosphorylation,bHLH transcription factor binding,cargo loading into vesicles,cellular response to epinephrine stimulus,and nucleoplasm.KEGG pathway enrichment analysis showed that target genes were mainly involved in the ErbB signaling pathway,HIF-1 signaling pathway,axon guidance,longevity regulatory pathway,endocrine resistance,glioma,choline metabolism in cancer,and EGFR tyrosine kinase inhibitor drug resistance.Molecular complex detection analysis by Cytoscape revealed that PIGH,RAF1,EGFR,NXT2,PIK3CD,PIK3R3,ERBB4,TRMT13,and C5orf22 were the key modules of miR-7-5p target gene clustering.Conclusion The expression of miR-7-5p in pancreatic cancer tissues positively correlated with the radiosensitivity of ^(125)I seeds.Via targeted gene regulation,miR-7-5p acts on the network of multiple signaling pathways in PDAC and participates in its occurrence and development.Thus,miR-7-5p may become a predictive index of ^(125)I seed implantation therapy sensitivity in PDAC patients.

3D打印共面坐标模板辅助125^Ⅰ放射性粒子植入治疗盆壁复发宫颈癌的剂量学研究

目的 探讨放疗后盆壁复发宫颈癌患者采用3D打印共面坐标模板（3D-PCT）辅助125I放射性粒子植入治疗剂量精确性实施的可行性。方法 本研究为单中心的回顾性研究，选取2016年4月至2017年12月北京大学第三医院应用3D-PCT辅助125I放射性粒子植入治疗的放疗后盆壁复发宫颈癌患者资料10例。患者年龄37~71岁，中位年龄53.5岁，KPS评分≥ 70分。所有患者均接受过盆腔放疗。病灶体积为3.5~58.0 cm3（中位31.9 cm3），处方剂量120~180 Gy，粒子活度0.55~0.67 mCi（1 Ci=3.7×1010Bq），术前计划植入粒子数目为50（12~81）颗。根据术前计划在3D-PCT引导下行放射性粒子植入术。术后实际植入粒子数目为53（10~82）颗。评估剂量学参数包括D90、D100、V100、V150、V200、靶区外体积指数（EI）、适形指数（CI）和均匀性指数（HI），以及危及器官剂量D2 cm3、D1 cm3和D0.1 cm3。术前计划与术后计划参数的比较采用相关样本非参数检验。结果 术后实际植入粒子数目多于术前计划设计，差异有统计学意义（Z=-2.255，P〈0.05）。术后计划与术前计划的靶区剂量学参数D90、D100、V100、V150、V200、EI、CI和HI比较，差异均无统计学意义（P〉0.05）。膀胱、肠道的D2 cm3、D1 cm3和D0.1 cm3、直肠D0.1 cm3的术后计划与术前计划剂量差异均无统计学意义（P〉0.05）。直肠D2 cm3和D1 cm3术后计划剂量低于术前计划，差异均有统计学意义（Z=-2.100、-2.240，P〈0.05）。结论 3D-PCT辅助125I放射性粒子植入治疗盆壁复发宫颈癌，通过术中剂量优化，术后实际剂量达到术前计划设计，可以保证125I放射性粒子植入盆壁复发宫颈癌的剂量精确实施。

腮腺粘液表皮样癌术后行组织内^(125)Ⅰ放射性粒子治疗临床观察

目的:探讨^(125)Ⅰ放射性粒子在腮腺粘液表皮样癌术后行组织间植入的治疗效果。方法:腮腺粘液表皮样癌病例36例随机分为两组,A组16例腮腺粘液表皮样癌作常规腮腺恶性肿瘤根治手术。B组20例行保留面神经腮腺并肿瘤切除术,尽量将肿瘤切除干净,然后在怀疑有肿瘤残留或安全边界不足处放置125I放射性粒子作为术后辅助治疗。两组病例在性别、年龄、UICC分期、病理分级之间均无显著性差异。术后随访,观察两组病例治疗效果。结果:A组13例有面瘫症状,4例复发;B组无一例出现面瘫症状,无一例复发。结论:腮腺粘液表皮样癌术后辅以放射性粒子植入组织内放疗疗效可靠且方法安全、操作简便,可有效降低腮腺粘液表皮样癌术后并发症和复发率。

Personalized radioprotection in tumor patients after^(125)I seed brachytherapy

Objective:To investigate patient-specific radioprotection mathods for people in close contact with cancer patientstreated by 12I-seed implantation.Methods:The initial dose rates(D_(0))at distances of 30 and 100 cm from 80 patients who had undergone ^(125)I-seed implantation were measured within 24 h of the procedure.The dose rate at t(D_(t))and effective dose(E)were calculated according to the measurad vales of D.The appropriate precaution times for general adult family members,spouses,coworkers,and children or pregnant women were determined,and the relationships between and precaution time for different close-contact groups were derived by curve-fitting the corresponding data.Results:The mean D vahes of 80 patients at distanes of 30 and 100cm were(15.24±11.25)μSv/h and(1.96±2.63)μSv/h,respectively(P<0.05).The mean values and range of precaution time for general adult familymembers,spouses,coworkers,and children or pregnant women were(4.17±16.55),(102.93±49.22),(51.00±61.29),and(34.27±56.90)d(0-90.61),(0-234.01),(0-247.81),and(0-224.69)d,respectively.Furthemore,a logarithmic relationship betwen D and precaution time(Y)was observed for the different groujps.The equations of these relationships were detemined to be Y=-131.569+83.256 lnD_(0) for general adult family mambers,Y=—108.532+83.318 lnD_(0) for spouses,Y=25.470+83.318 lnD,for coworkers,and Y=2.585+83.229 lnD_(0) for children or pregnant women.Conchusions:Some cancer patients treated by ^(125)I-seed brachytherapy emitover-dose levels of γ-rays,necessitatingradiation protection for their close contacts.However,appropriate patient-specific radiation protection fordifferent close contacts can be determined based on the precaution time calculated using the D_(0) value.