国产6711型^(125)I粒子源剂量学参数模拟研究

采用MCNP软件对国产6711型^(125)I粒子源剂量率常数、径向剂量函数、一维各向异性函数和二维各向异性函数等四个剂量学参数进行模拟计算研究。结果表明,剂量率常数与TG 43-U1报告推荐值误差为-0.83%;获得了(0.05~10)cm范围内的径向剂量函数,并对(0.25~10)cm范围数据进行五阶多项式拟合,提高了拟合函数的精度;得到(0.25~7)cm范围内的一维各项异性函数和二维各向异性函数,通过与文献比较,发现国产6711型粒子源源芯结构的差异会引起一维各向异性函数和二维各向异性函数的偏大现象。

A pilot study on combination of cryosurgery and ^(125)iodine seed implantation for treatment of locally advanced pancreatic cancer

AIM: To study the therapeutic value of combination o cryosurgery and 125iodine seed implantation for locally advanced pancreatic cancer. METHODS: Forty-nine patients with locally advanced pancreatic cancer (males 36, females 13), with a median age of 59 years, were enrolled in the study. Twelve patients had liver metastases. In all cases the tumors were considered unresectable after a comprehensive evaluation. Patients were treated with cryosurgery, which was performed intraoperatively or percutaneously unde guidance of ultrasound and/or computed tomography (CT), and 125iodine seed implantation, which was performed during cryosurgery or post-cryosurgery under guidance of ultrasound and/or CT. A few patients received regional celiac artery chemotherapy. RESULTS: Thirteen patients received intraoperative cryosurgery and 36 received percutaneous cryosurgery Some patients underwent repeat cryosurgery. 125Iodine seed implantation was performed during freezing procedure in 35 patients and 3-9 d after cryosurgery in 14 cases. Twenty patients, 10 of whom had hepaticmetastases received regional chemotherapy. At 3 mo after therapy, CT was repeated to estimate tumor response to therapy. Most patients showed varying degrees of tumor necrosis. Complete response (CR) of tumor was seen in 20.4% patients, partial response (PR), in 38.8%, stable disease (SD), in 30.6%, and progressive disease (PD), in 10.2%. Adverse effects associated with cryosurgery included upper abdomen pain and increased serum amylase. Acute pancreatitis was seen in 6 patients one of whom developed severe pancreatitis. All adverse effects were controlled by medical management with no poor outcome. There was no therapy-related mortality. During a median follow-up of 18 mo (range of 5-40), the median survival was 16.2 mo, with 26 patients (53.1%) surviving for 12 mo or more. Overall, the 6-, 12-, 24- and 36-mo survival rates were 94.9%, 63.1%, 22.8% and 9.5%, respectively. Eight patients had survival of 24 mo or more. The patient with the longest survival (40 mo) is still living without evidence of tumor recurrence. CONCLUSION: Cryosurgery, which is far less invasive than conventional pancreatic resection, and is associated with a low rate of adverse effects, should be the treatment of choice for patients with locally advanced pancreatic cancer. 125Iodine seed implantation can destroy the residual surviving cancer cells after cryosurgery. Hence, a combination of both modalities has a complementary effect.

Similar therapeutic effects of ^(125I) seed radiotherapy andγ-ray radiotherapy on lacrimal gland adenoid cystic carcinoma

AIM:To evaluate the survival outcomes of patients with lacrimal gland adenoid cystic carcinoma who underwent eye-sparing surgery combined with ^(125I)seed implantation radiotherapy or local externalγ-ray radiotherapy.METHODS:In this retrospective comparative case series,the clinical records of 27 primary and 8 recurrent patients were reviewed.Univariate and multivariate analyses were used to identify risk factors associated with distant metastasis(DM),and the overall survival(OS)after the initial surgery was analyzed.RESULTS:The median follow-up after radiotherapy was 36 mo(range 6-120 mo).At the last follow-up after radiotherapy,26(74.3%)patients had no evidence of disease,7(20%)patients had DM,2(5.9%)patients died of DM,and 1 patient with DM was lost to follow-up.Univariate analyses showed that duration of symptoms,bone destruction,T stage classification,and wide excision surgery were risk factors influencing DM(P<0.05).The 5-year and 10-year OS rates after the initial surgery were 95.8%and 79.9%,respectively.The 5-year DM-free survival and disease-free survival rates after radiotherapy were 66.4%and 52.7%,respectively.CONCLUSION:^(125I)seed radiotherapy and local externalγ-ray radiotherapy may have similar therapeutic effects in preventing DM.Patients with T1/T2 stage disease have a better prognosis than those with T3/T4 stage disease.

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.

Symbiotic nitrogen fixation in black locust (Robinia pseudoacacia L.) seedlings from four seed sources

We conducted a greenhouse experiment to investigate the role of seed source in growth and symbiotic nitrogen fixation of black locust （Robinia pseudoacacia L）. Seeds from different sources were planted in the same environmental conditions and inoculated with a suspension of mixed Rhizobium. We used the modified ^15N isotope dilution method to estimate biological nitrogen fixation of Robinia trees. Different Robinia seed sources differed significantly in terms of tissue dry weight （50.6-80.1 g）, total N （1.31-2.16 g） and proportion of nitrogen derived from the atmosphere （ 0-51%）. A higher nitrogen fixation rate of Robinia trees was associated with higher dry weight. Moreover, the leaves of Robinia proved to adequately represent the nitrogen fixation capacity of entire plants. Our results confirmed that assessment of seed sources is a useful way to improve the nitrogen fixation capacity and therefore the growth rate of Robinia.

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.

^(125)I种子源组织间植入近距离治疗恶性肿瘤的疗效观察

目的:探讨125I种子源组织间植入近距离治疗恶性肿瘤的疗效。方法:采用125I种子源对71例各类恶性肿瘤患者进行组织间植入治疗,其中51例患者于术中将125I种子源植入肿瘤切除后可能残留区域或不能切除的肿瘤组织内;20例患者在B超、CT引导下经皮穿刺将125I种子源植入到肿瘤内,所有患者均获随访。结果:所有患者治疗后均恢复良好,主观症状明显改善,未发现与125I种子源植入相关的并发症。71患者血象虽较治疗前有所升高(P<0．05),但仍在正常范围内,而免疫球蛋白水平变化不大(P>0．05),各类患者相应肿瘤标志物水平在治疗后亦显著下降(P<0．01)。71例患者治疗总有效率为87．3％,其中完全缓解12例(占16．9％);部分缓解50例(占70．4％);稳定7例(占9．8％);进展2例(占2 8％)。结论:125I种子源组织间植入近距离治疗恶性肿瘤方法简便、安全,近期疗效确切,为恶性肿瘤的综合治疗提供了新的手段。

一种大尺寸^(125)I籽源水中剂量分布的模拟与实验研究

本文利用蒙特卡罗程序MCNP模拟计算了一种新型大尺寸的^(125)I籽源在水中的剂量率的轴向与径向分布,并且采用热释光剂量计(TLD)法对该籽源水中的剂量分布进行了实验测量。实验与模拟结果趋势相符,剂量率均随离源距离与距籽源中心平面高度的增加而迅速降低。本文的研究对该大尺寸^(125)I籽源后续的临床试验与应用具有重要的参考价值。

医用^(125)I种子源表观活度的电离室测量

研究了125I种子源的自屏蔽、不同容器和容器的形状、源的几何位置等对125I种子源表观活度测量的影响。结果表明,低能125I种子源表观活度的测量只有在严格规定的条件下才能进行较准确的测量。因此为用户测量125I种子源的表观活度提供几点建议:选用材质为聚丙烯的标准尖底放免管作为测量容器;逐个测量;测量时,源必须放在托盘中心。

A case report of iodine-125 seed placement during operation for the treatment of advanced gallbladder carcinoma with septic shock

This case report describes a patient with advanced gallbladder cancer who developed septic shock associated with iodine-125(^(125)I)seed implantation.The treatment process is described to provide a clinical reference for similar cases.A 52-year-old woman with recurrence of advanced gallbladder cancer underwent ^(125)I seed implantation and developed postoperative sepsis with septic shock.The blood culture suggested infection with Aeromonas caviae and Enterococcus faecalis.Vancomycin and imipenem were immediately administered according to the drug sensitivity results,along with immunoglobulin therapy and vasoactive drugs.The patient’s condition gradually stabilized after comprehensive treatment.Sepsis with septic shock is a rare but potentially fatal complication of ^(125)I seed implantation.Timely administration of broad-spectrum antibiotics,immunoglobulin therapy,and vasoactive drugs is very important to stabilize the patient’s condition.Our treatment of this patient can serve as a reference for clinicians to manage this complication in similar cases.

^(125)I种籽源植入手术中工作人员的电离辐射防护

为探讨操作125I种籽源应采取适当防护措施的必要性,阐述了125I种籽源植入手术各阶段的电离辐射监测结果,并对无防护条件下手术医生可能受到的辐射剂量做出估算:对于总活度为925 MBq的40粒种籽源,在开源、核对及装源入植源器操作时,操作距离30 cm,操作时间10 min,则操作者受照剂量为70μSv;对于手术医生,从辐射防护角度进行估计,一例手术,包括插植和带源缝合操作,医生在其操作位置的受照剂量可达184μSv。并对125I种籽源植入手术中工作人员的电离辐射防护提出了建议。

Treatment of Unresectable Advanced Gastric Cancer Using lodine-125 Brachytherapy

OBJECTIVE The purpose of the study was to examine the efficacy of treating patients with advanced gastric cancer using iodine-125 （^125Ⅰ） brachytherapy. METHODS Ten patients with unresectable advanced gastric cancer were selected based on their pattern of CT scans. We utilized a brachytherapy planning system to determine the distribution of the ^125Ⅰ seeds, their activity and quantity. The matched peripheral dose （MPD） was 110-135 Gy.^125Ⅰ seeds were implanted in a single plane or biplane by an intraoperative small incision or percutaneous puncture. The postoperative hemogram, CT, KPS, pain-relieving period and survival period were recorded. RESULTS One patient developed a complete response （CR）, 4 patients a partial response （PR）, 3 patients showed no change （NC） and 2 patients developed progressive disease （PD）. The overall response rate （CR＋PR） was 50% （5/10）. The pain-relieving rate was 89% （8/9）. The patients＇ appetite and KPS were improved. The longest survival period was 10 months and median life span was 4 months. There were 8 patients whose seeds fell off resulting in an expulsion rate of 3.8% （26/692）. The patients showed 0-1 degree acute radio-therapeutic side-effects without other symptoms such as abdominal pain, vomitus cruentes or intestinal obstruction etc.CONCLUSION Applying ^125Ⅰ implantation to treat advanced gastric cancer with a reasonable seed distribution can significantly improve clinical symptoms and their quality of life. The radioactive damage is mild. This method can be used as an important supplementary treatment for unresectable advanced gastric cancer.

CT guided ^125iodine seed implantation for portal vein tumor thrombus in primary hepatocellular carcinoma

Background This study evaluated the clinical application of CT guided ^125iodine implantation in patients with portal vein tumor thrombus in primary hepatocellular carcinoma. Methods The ten patients （9 males and 1 female, aged from 36 to 72 years） with portal vein tumor thrombus accompanying hepatocellular carcinoma had been treated with comprehensive therapy including surgery, transcatheter arterial chemoembolization, radiotherapy ablation, microwave ablation or percutaneous ethanol injection. The average diameter of each tumor thrombus was 21.5 mm × 30.5 mm. Seeds of 30 MBq ^125I were implanted 5 mm apart within the portal vein tumor thrombus. The follow-up after 4 months included enhanced spiral CT. Results CT screening of the tumours indicated that 4 out of 10 patients showed complete response to the therapy, 5 partial response and 1 stable disease. Adverse effects included aggravated abdominal dropsy and temporarily increased transaminase, which were controlled by medical management. Severe complications such as haemorrhage, biliary fistula hepatic abscess, pancreatic fistula and hepatic function failure were not observed. Implanted seeds migrated to lung and left hepatic lobe in 1 case. Conclusion CT guided implantation of ^125iodine seeds, can effectively treat portal vein tumor thrombus accompanying hepatocellular carcinoma with minimal damage and few complications.

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.

^125I粒子源近距离治疗前列腺癌模型的剂量学研究

目的研究放射性^125I粒子源在治疗前列腺癌中的剂量分布，探寻治疗计划系统（TPS）优化效果的有效方法。方法选定1个治疗计划系统，应用热释光剂量计，基于前列腺癌等效模体，模拟测量前列腺癌中的剂量分布。模拟植入共89颗^125I粒子，每个粒子的活度为1．37×10^7Bq（±5％）。结果各层的最大剂量为151—241Gy，与处方剂量145Gy的偏差在4．1％～66．O％。各层的最小剂量在101—128Gy，与处方剂量的偏差在12％-30％。离模体边缘10mm处正常组织的最大剂量为46—91Gy，偏差为44％～63％。结论该系统对实际的粒子植入治疗，评估TPS提供了实用的方法。

热释光剂量仪测量体模植入125I粒子源的剂量学参数可行性

目的 探讨应用热释光剂量仪在体模中测量植入125I粒子源（型号Sinko BT-125-1）的剂量学参数可行性.方法 将测量体模进行改进使其可适用于剂量学测量.根据AAPM TG43建议测量的参数包括剂量率常数Λ、径向剂量函数gL（r）和各向异性函数F（r,θ）等,所测数据与文献中其他构造相似的125I粒子源数据进行比较.结果 125I粒子源的Λ为0.928 cGyh-1 U-1.所测得的gL（r）范围为径向距离在1.0～10.0cm内所对应的值.F（r,θ）范围为角度在0.～90.内所对应的值.与型号Amersham 6711 125I粒子源相比,二者gL（r）值的最大差异为9.6％.二者F（r=2 cm,θ=0）值的差异为10.2％.应用此体模进行测量总的不确定度＜6.0％.结论 测量结果具备较小的不确定性和良好自洽性,故应用热释光剂量仪体模测量永久植入粒子源的剂量学参数是可行的.

Particle implantation combined with chemotherapy for rhabdomyosarcoma of the head and neck:A 8-year long-term follow-up case report

Rhabdomyosarcomas(RMSs)are highly malignant soft-tissue sarcomas.Head and neck RMSs often pose unique challenges to treatment because of their closeness to important structures.We here report a rare case of a 1-year-old boy with a 1-month history of right eye swelling and an eye mass.Biopsy of deep tumors in the maxillofacial region supports embryonal RMS.Postoperative positron emission computed tomography showed a 5.0 cm×4.8 cm×4.2 cm malignant tumor in the right maxillary region.In accordance with the international RMS study group guideline,the child was diagnosed with IIIa and TNM stage T2bN1M1 embryonal RMS.The child was treated with a combination of chemotherapy and ^(125)I seed implantation radiotherapy and eventually achieved partial remission.This case report shows that ^(125)I seed implantation is a safe and effective means of delivering radiotherapy to young children with head and neck RMSs.It may be an option for children with RMSs for whom surgery or external radiotherapy is unsuitable.

粒子植入术后肿瘤缩小时不同布源方式对剂量的影响

目的 假定125I粒子植入术后肿瘤每月以20%速度退缩时，研究等间距与周边密集、中间稀疏2种布源方式对剂量的影响。方法 利用计算机三维治疗计划系统（TPS）勾画4 cm×5 cm的圆柱形肿瘤，根据布源方式不同分为等间距组和周边密集、中间稀疏组，以处方剂量125 Gy载入放射性活度1.85×107Bq 125I粒子行术前计划。假设125I粒子植入肿瘤后肿瘤高不变，直径每月以20%的速度缩小，粒子随肿瘤均匀向心性集中，分别计算125I粒子植入术后0、1、2、3个月时90%靶体积吸收剂量（D90）、90%处方剂量覆盖体积占靶体积的百分比（V90）、150%处方剂量覆盖体积占靶体积的百分比（V150）。结果 等间距组载入粒子85颗，植入0、1、2、3个月后的D90分别为126.20、130.41、133.82和139.48 Gy，V90分别为97.0%、98.1%、99.3%和100%，V150分别为70.2%、69.9%、71.1%和71.5%；周边密集、中间稀疏组植入粒子75颗，植入0、1、2、3个月后的D90分别为126.46、125.41、123.50和128.83 Gy，V90分别为95.2%、95.7%、94.9%和97.6%，V150分别为52.8%、60.4%、62.7%和59.3%。结论 当肿瘤直径每个月以20%速度退缩时，粒子等间距分布时肿瘤预期吸收剂量逐渐增加；周边密集、中间稀疏的布源方式肿瘤预期吸收剂量不变，且高剂量区范围明显小于等间距布源。

某医院粒籽源永久性植入治疗病房的剂量监测结果分析

目的研究某医院粒籽源永久性植入治疗病房内的外照射剂量水平和分布情况,对其辐射风险进行评估,为加强粒籽源永久性植入治疗放射工作人员的放射防护与监督提供科学依据,同时提出合理化的辐射防护建议。方法采用热释光剂量测量方法对粒籽源永久性植入治疗病房内10类区域的剂量水平进行为期1年的监测,并结合病人植入粒籽源数目和住院天数进行剂量分析。结果该病区一年内共收住病人1232人次,其中行粒籽源永久性植入治疗病人432人次(190人),共植入粒籽源2.746843×10^(11) Bq(7423.9 mCi),人均6.3566×10^(8) Bq(17.18 mCi),粒籽源永久性植入治疗病人年度住院天数2478天,平均住院6天。热释光剂量监测结果表明,各监测点处的剂量范围为0.23~13.94 mSv,均值为3.37 mSv,中值为1.90 mSv。其中病床两侧和输液架处的剂量范围明显高于其他点位处,经剂量/活度和剂量/(活度·天)分析,其差异依旧存在,均存在统计学差异。结论该粒籽源永久性植入病房内存在外照射剂量偏高的点位,医护人员和陪护人员应减少在此点位居留的时间或远离此点位。医护人员年度个人剂量监测结果远低于国家标准要求,亦低于本次实验点位剂量监测结果,与医护人员的实际工作和居留情况有关。工作人员在穿戴防护用品的情况下,在剂量安全范围内,可适当增加粒籽植入活度和住院天数。患者在术后穿戴防护,可明显降低其对医护人员的外照射剂量。