I-125

  • 文章类型: Multicenter Study
    目的:Pd-103和I-125通常用于前列腺癌的低剂量率(LDR)近距离放射治疗。同位素类型的结果比较有限,但是Pd-103比I-125具有明显的放射生物学优势,尽管其在美国以外的可用性较低.我们评估了Pd-103与I-125LDR单药治疗前列腺癌后的肿瘤学结果。
    方法:我们回顾性分析了8个机构中接受Pd-103(n=1,597)或I-125(n=7,504)治疗前列腺癌的确定性LDR单药治疗的男性的数据库。通过Kaplan-Meier单变量和Cox多变量分析,分析了通过同位素分层的无临床衰竭(FFCF)和无生化衰竭(FFBF)。对随访至少3.5年的男性,按同种型计算生化治愈率(3.5至4.5年随访期间前列腺特异性抗原水平≤0.2ng/mL),并通过单变量和多变量逻辑回归进行比较。
    结果:与I-125相比,Pd-103导致较高的7年FFBF率(96.2%vs87.6%,P<0.001)和FFCF(96.5%vs94.3%,P<0.001)。在对基线因素进行多变量校正后,这种差异仍然存在(FFBF风险比[HR]=0.31,FFCFHR=0.49,均P<0.001)。Pd-103在单变量分析(比值比[OR]=5.9,P<0.001)和多变量分析(OR=6.0,P<0.001)中也与较高的治愈率相关。结果在使用两种同位素的4个机构的数据的敏感性分析中保留了显著性(n=2,971)。
    结论:Pd-103单药治疗与较高的FFBF相关,FFCF,和生化治愈率,提示与I-125相比,Pd-103LDR可改善肿瘤学结局.
    Pd-103 and I-125 are commonly used in low dose rate (LDR) brachytherapy for prostate cancer. Comparisons of outcomes by isotope type are limited, but Pd-103 has distinct radiobiologic advantages over I-125 despite its lesser availability outside the United States. We evaluated oncologic outcomes after Pd-103 vs I-125 LDR monotherapy for prostate cancer.
    We retrospectively analyzed databases at 8 institutions for men who received definitive LDR monotherapy with Pd-103 (n = 1,597) or I-125 (n = 7,504) for prostate cancer. Freedom from clinical failure (FFCF) and freedom from biochemical failure (FFBF) stratified by isotope were analyzed by Kaplan-Meier univariate and Cox multivariate analyses. Biochemical cure rates (prostate-specific antigen level ≤ 0.2 ng/mL between 3.5 and 4.5 years of follow-up) by isotype were calculated for men with at least 3.5 years of follow-up and compared by univariate and multivariate logistic regression.
    Compared with I-125, Pd-103 led to higher 7-year rates of FFBF (96.2% vs 87.6%, P < 0.001) and FFCF (96.5% vs 94.3%, P < 0.001). This difference held after multivariate adjustment for baseline factors (FFBF hazard ratio [HR] = 0.31, FFCF HR = 0.49, both P < 0.001). Pd-103 was also associated with higher cure rates on univariate (odds ratio [OR] = 5.9, P < 0.001) and multivariate (OR = 6.0, P < 0.001) analyses. Results retained significance in sensitivity analyses of data from the 4 institutions that used both isotopes (n = 2,971).
    Pd-103 monotherapy was associated with higher FFBF, FFCF, and biochemical cure rates, and suggests that Pd-103 LDR may lead to improved oncologic outcomes compared with I-125.
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  • 文章类型: Journal Article
    背景:这项研究测量并计算了全眼放射治疗(治疗视网膜母细胞瘤)的独特金斑周围的剂量分布。涂药器由连接在四个眼外肌和四条腿上的角膜环组成,每个都装有I-125种子。它们插入在每对肌肉之间的结膜下方,并附着在环的前部。涂药器以这样的方式设计,使得剂量指向眼睛的中部,同时避开周围组织。
    目的:(I)为了比较通过固体-水体模中的热释光剂量计(TLD)获得的测量和计算数据,固体水幻影中的Gafchrome薄膜,治疗计划系统,和蒙特卡罗模拟;(II)通过考虑金屏蔽和各向异性,使用蒙特卡罗模拟来确定对处于危险中的器官的剂量。
    方法:在眼形固体-水体模中使用TLD和GafchromyEBT2膜测量涂药器周围的剂量。使用TheraPlanPlus和BrachyVision计划系统以及使用egs_brachy代码的蒙特卡罗模拟进行剂量计算。创建了施加器的计算机辅助设计图,并将其用于创建MonteCarlo模拟的输入文件。
    结果:蒙特卡洛计算的视神经剂量是眼睛中心剂量的64.8%,而计划剂量为93.7%。蒙特卡罗透镜剂量从72.0%到86.1%不等,而计划剂量从73.0%到84.3%不等。蒙特卡罗计算的骨轨道剂量为11.3%,而与眼睛中心区域的剂量相比,计划剂量高达54.7%。
    结论:测量和蒙特卡罗模拟的剂量分布匹配良好,而计划的剂量分布在眼睛的某些区域和眼外显示出差异,因为他们对斑块的屏蔽作用一无所知。
    BACKGROUND: This study measured and calculated dose distributions around a unique gold plaque for whole-eye radiotherapy (to treat retinoblastoma). The applicator consists of a pericorneal ring attached to the four extraocular muscles and four legs, each loaded with I-125 seeds. They are inserted beneath the conjunctiva in-between each pair of muscles and attached anteriorly to the ring. The applicator was designed in such a way that the dose is directed toward the middle of the eye while sparing surrounding tissues.
    OBJECTIVE: (I) To compare the measured and calculated data obtained by thermoluminescent dosimeters (TLDs) in a solid-water phantom, a Gafchromic film in a solid-water phantom, the treatment planning systems, and Monte Carlo simulations; (II) to use Monte Carlo simulations for the determination of the dose to the organs at risk by taking the gold shielding and the anisotropy into account.
    METHODS: The dose around the applicator was measured using TLDs and Gafchromic EBT2 film in eye-shaped solid-water phantoms. Dose calculations were performed with the TheraPlan Plus and BrachyVision planning system and Monte Carlo simulations with egs_brachy code. A computer-aided design drawing of the applicator was created and used to create the input file for the Monte Carlo simulations.
    RESULTS: Monte Carlo calculated dose to the optic nerve is 64.8% of the central dose in the eye, whereas the planned dose is 93.7%. The Monte Carlo lens dose varies from 72.0% to 86.1%, whereas the planned dose varies from 73.0% to 84.3%. Monte Carlo-calculated dose to the bony orbit is 11.3%, whereas the planned dose is as high as 54.7% compared to the dose in the center region of the eye.
    CONCLUSIONS: The measured and Monte Carlo-simulated dose distributions matched well, whereas planned dose distributions showed discrepancies in some areas of the eye and outside of the eye due to their ignorance of the shielding effects of the plaque.
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  • 文章类型: Journal Article
    BACKGROUND: Stent insertion is the most frequently used option to treat malignant biliary obstruction (MBO) patients. Hilar cholangiocarcinoma (HCCA) is the most common disease that causes hilar MBO.
    OBJECTIVE: To assess the clinical efficacy and long-term outcomes of I-125 seed-loaded stent (ISS) insertion for HCCA patients.
    METHODS: Consecutive patients with HCCA underwent either normal stent (NS) or ISS insertion between January 2017 and December 2019. The baseline and treatment data of these two groups were compared.
    RESULTS: During the period, a total of 93 patients with inoperable HCCA were divided into either NS (n = 48) or ISS (n = 45) insertion groups at our centre. Technical success rates of the NS and ISS insertion were 91.7% and 95.6%, respectively (p = 0.733). Clinical success rates were 93.2% and 100% in the NS and ISS groups, respectively (p = 0.24). Stent dysfunction was observed in 11 and 8 patients in the NS and ISS groups, respectively (p = 0.47). The median stent patency was 143 days and 208 days in the NS and ISS groups, respectively (p < 0.001). All patients died in the follow-up period, with median survival duration of 178 days and 220 days in the NS and ISS groups, respectively (p < 0.001). ISS insertion was the only predictor of longer patency (p = 0.002) and survival (p = 0.01).
    CONCLUSIONS: ISS insertion might achieve longer patency and overall survival in patients with inoperable HCCA as compared with NS insertion.
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  • 文章类型: Journal Article
    BACKGROUND: Malignant esophageal obstruction is usually caused by esophageal and other chest cancers. More than 80% of cases of obstructive esophageal cancer (OEC) have lost the chance of curative resection. Stent insertion is a first-line palliative approach used to treat incurable OEC.
    OBJECTIVE: To gauge the relative clinical efficacy of I-125 seed-loaded stent (ISS) versus normal stent (NS) insertion as a treatment for OEC.
    METHODS: Querying of the PubMed, Embase, and Cochrane Library databases was conducted to find all relevant studies published up to November 2020. The meta-analysis was undertaken using RevMan v5.3.
    RESULTS: We identified 158 studies initially, eight (4 randomized controlled trials and 4 retrospective studies) of which were used in this meta-analysis. We found that the two groups exhibited the comparable pooled Δdysphagia scores (MD = 0.02; p = 0.80), stent restenosis rates (OR = 0.97; p = 0.89), stent migration rates (OR = 0.81; p = 0.63), severe chest pain rates (OR = 1.05; p = 0.81), hemorrhage rates (OR = 1.53; p = 0.16), aspiration pneumonia rates (OR = 0.72; p = 0.38), and fistula formation rates (OR = 1.47; p = 0.44). The pooled time-to-restenosis and survival were both significantly longer in the ISS group (p = 0.04 and < 0.0001, respectively). Significant heterogeneity was detected in the endpoints of Δdysphagia scores and survival (I2 = 73% and 86%, respectively). Funnel plot analysis indicated an absence of publication bias related to the selected study endpoints.
    CONCLUSIONS: For patients with OEC, our meta-analysis indicated that ISS insertion could provide longer stent patency and survival than NS insertion.
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  • 文章类型: Journal Article
    Interstitial intracranial radiotherapy implants, or brachytherapy, is an adjuvant option for treatment of recurrent high-grade meningiomas after resection. The implants are placed in the resection cavity following tumor resection. The most commonly used isotope is Iodine-125 (I-125). While there are no controlled studies comparing treatment of meningiomas with or without brachytherapy, several case series report good long-term survival, suggesting that this may be a useful adjuvant for recurrent high-grade tumors. Complications can occur including radiation necrosis, impaired wound healing, hydrocephalus and infection. In the future, new isotopes are being explored that may have fewer complications and better safety profiles.
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  • 文章类型: Journal Article
    The purpose of this study was to investigate the rate of compliance of air kerma strength (AKS) measurements of iodine-125 (I-125) seeds with international recommendations by departments in Australia and determine the potential impact of noncompliance.
    To achieve this aim, we present an intercomparison of AKS measurements for a single I-125 seed performed by 11 radiotherapy departments in Australia. Measurements were performed at two sites, with each participating department traveling to one of the two host sites and measuring the AKS using their own equipment and local protocols. Each of the AKS measurements was compared with each other and the manufacturer-certified AKS.
    Nine of the 11 participating departments measured AKS fell within ±3% of the manufacturer\'s calibration certificate value, whereas all participating departments measured AKS within ±5% of the manufacturer\'s calibration certificate value. The total spread of the measured AKS among the 11 departments was 7.7%. Only two of the 11 participating departments complied with international recommendations and had their well chamber calibrated within the last 2 years. In addition, 2 of the 11 departments used a well chamber calibrated that was calibrated with a different seed model used during the intercomparison, whereas 4 of the 11 departments calibrated their well chamber \"in-house\" using a factory-calibrated seed provided by the seed manufacturer.
    A significant variation in the methods used and frequency of calibration of well chambers were observed among the participating departments. The results of this study support the international recommendations on frequency and methodology of well chamber calibration. Failure to follow these recommendations significantly increases the uncertainty in AKS measurement of I-125 seeds.
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  • 文章类型: Comparative Study
    Designed ankyrin repeat proteins (DARPins) are small engineered scaffold proteins that can be selected for binding to desirable molecular targets. High affinity and small size of DARPins render them promising probes for radionuclide molecular imaging. However, detailed knowledge on many factors influencing their imaging properties is still lacking. We have evaluated two human epidermal growth factor 2 (HER2)-specific DARPins with different size and binding properties. DARPins 9_29-H6 and G3-H6 were radiolabeled with iodine-125 and tricarbonyl technetium-99m and evaluated in vitro. A side-by-side comparison of biodistribution and tumor targeting was performed. HER2-specific tumor accumulation of G3-H6 was demonstrated. A combination of smaller size and higher affinity resulted in a higher tumor uptake of G3-H6 in comparison to 9_29-H6. Technetium-99m labeled G3-H6 demonstrated a better biodistribution profile than 9_29-H6, with several-fold lower uptake in liver. Radioiodinated G3-H6 showed the best tumor-to-organ ratios. The combined effect of affinity, molecular weight, scaffold composition, and nonresidualizing properties of iodine label provided radioiodinated G3-H6 with high clinical potential for imaging of HER2.
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  • 文章类型: Journal Article
    Background and Objectives Intra-parenchymal brain surgical resection cavities usually contract in volume following low dose rate (LDR) brachytherapy implants. In this study, we systematically modeled and assessed dose variability resulting from such changes for I-125 versus Cs-131 radioactive sources. Methods Resection cavity contraction was modeled based on 95 consecutive patient cases, using surveillance magnetic resonance (MR) images. The model was derived for single point source geometry and then fully simulated in 3D where I-125 or Cs-131 seeds were placed on the surface of an ellipsoidal resection cavity. Dose distribution estimated via TG-43 calculations and biological effective dose (BED) calculations were compared for both I-125 and Cs-131, accounting for resection cavity contractions. Results Resection cavity volumes were found to contract with an effective half-life of approximately 3.4 months (time to reach 50% of maximum volume contraction). As a result, significant differences in dose distributions were noted between I-125 and Cs-131 radioactive sources. For example, when comparing with static volume, assuming no contraction effect, I-125 exhibited a 31.8% and 30.5% increase in D90 and D10 values (i.e., the minimal dose to 90% and 10% of the volume respectively) in the peripheral target areas over the follow-up period of 20.5 months. In contrast, Cs-131 seeds only exhibited a 1.44% and 0.64% increase in D90 and D10 values respectively. Such discrepancy is likewise similar for BED calculations. Conclusion Resection cavity contractions affects Cs-131 dose distribution significantly less than that of I-125 for permanent brain implants. Care must be taken to account for cavity contractions when prescribing accumulative doses of a radioactive source in performing the brain implant procedures.
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  • 文章类型: Journal Article
    The aim of this study was to evaluate quality-of-life changes up to 10 years following three different radiotherapy concepts.
    In the years 2000-2003, 295 patients were treated with external beam radiotherapy (EBRT; n = 135; 70.2 Gy in 1.8 Gy fractions), low-dose-rate brachytherapy (LDR-BT with I-125; n = 94; 145 Gy), and high-dose-rate brachytherapy (HDR-BT with Ir-192; n = 66; 18 Gy in two fractions using 4-6 needles) as a boost to EBRT (50.4 Gy in 1.8 Gy fractions). Quality of life was assessed using the Expanded Prostate Cancer Index Composite at median time of 2, 6, and 10 years after treatment.
    The urinary function score 2 years after EBRT (mean 93 points) was significantly higher in comparison to HDR-BT + EBRT (80 points, higher doses to the urethra relevant) and LDR-BT (88 points). After 10 years, only HDR-BT + EBRT (75 points) remained worse (LDR-BT 92 points; EBRT 91 points). Urinary incontinence score decreased from 83 to 76 points in the HDR-BT + EBRT group. No significant differences or changes resulted in the bowel domain. The mean sexual function score (i.e., sexuality score) was significantly higher after LDR-BT versus HDR-BT + EBRT and EBRT (30 vs. 19 and 24 points after 2 years and 25 vs. 13 and 15 points after 10 years, respectively)-a lower patient age and a lower percentage with hormonal treatment need to be considered.
    Apart from decreasing sexual function for all patients, decreasing urinary scores were found in the HDR-BT + EBRT group predominantly as a result of increasing incontinence. This study demonstrates the need for optimum BT treatment planning.
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  • 文章类型: Journal Article
    三链体形成寡核苷酸(TFO)在体外和体内结合对DNA双螺旋特异性的序列,并且是操纵基因或基因调控元件的有希望的工具。TFO作为短程粒子发射器的载体分子,例如俄歇电子发射器(AEE),具有引入辐射诱导的位点特异性复杂DNA损伤的潜力,已知诱导染色体易位。我们研究了基因表达,用AEE碘-125(I-125)标记的TFO-BCL2靶向人BCL2基因转染后,SCL-II细胞中的易位频率和蛋白质表达。TFO-BCL2与BCL2基因结合,紧邻已知的主要断裂区域(mbr)。用I-125标记的TFO转染SCL-II细胞并储存用于衰变积累。用荧光原位杂交(FISH)方法进行BCL2易位的监测。利用的FISH探针设计用于检测BCL2基因的t(14;18)易位,这是导致BCL2蛋白过表达的常见易位。通过定量实时PCR进行BCL2基因表达水平的分析。通过蛋白质印迹分析在蛋白质水平上的基因表达的验证。与对照相比,在I-125-TFO-BCL2转染的细胞中BCL2的相对基因表达显示出显著的上调。对BCL2t(14;18)易位频率的分析显示,当与对照细胞相比时,显著增加1.8至2倍。这种2倍的增加没有反映在蛋白质水平上。我们得出的结论是,BCL2基因内的I-125衰变促进了SCL-II细胞中的t(14;18)染色体易位,并且频率的增加有助于观察到的BCL2基因表达的总体增强。
    Triplex-Forming oligonucleotides (TFO) bind sequence-specific to the DNA double helix in-vitro and in-vivo and are a promising tool to manipulate genes or gene regulatory elements. TFO as a carrier molecule for short-range particle emitter such as Auger-Electron-Emitters (AEE) bear the potential to introduce radiation-induced site-specific complex DNA lesions, which are known to induce chromosomal translocations. We studied gene expression, translocation frequency and protein expression in SCL-II cells after transfection with the AEE Iodine-125 (I-125) labeled TFO-BCL2 targeting the human BCL2 gene. The TFO-BCL2 binds to the BCL2 gene in close proximity to a known major-breakage-region (mbr). SCL-II cells were transfected with I-125 labeled TFO and stored for decay accumulation. Monitoring of BCL2 translocations was done with the Fluorescence-In-Situ-Hybridization (FISH) method. The utilized FISH probes were designed to detect a t(14;18) translocation of the BCL2 gene, which is a common translocation leading to an overexpression of BCL2 protein. Analysis of BCL2 gene expression levels was done via quantitative Real-Time PCR. Verification of gene expression on the protein level was analyzed by Western blotting. The relative gene expression of BCL2 in I-125-TFO-BCL2 transfected cells showed a significant up-regulation when compared to controls. Analysis of the BCL2 t(14;18) translocation frequency revealed a significant 1.8- to 2-fold increase when compared to control cells. This 2-fold increase was not reflected on the protein level. We conclude that I-125 decays within the BCL2 gene facilitate the t(14;18) chromosomal translocation in the SCL-II cells and that the increased frequency contributes to the observed overall enhanced BCL2 gene expression.
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