山东省环境中氡及其子体浓度与所致剂量的研究

本文采用闪烁法和Thomas三段法测量了山东省室外148个测量点的氧浓度、92个测量点的氧子体浓度, 其几何均值分别为4.76Bq·m^-3、1.54×10^-3J·m^-3 F值为0.60；室内46个测量点的氡及其子体浓度, 几何均值分别为18.0Bq·m^-3、4.50×10^-8·Jm^-3 F值为0.45。室内、外氡及其子体浓度均遵从对数正态分布。垒省每个居民吸八氧及其子体所致年有效剂量当量为0.58mSv。     

福建地区空气中氡及其子体浓度与剂量评价

采用双滤膜法和快速潜能测定法测定了福建省住宅室内、室外以及地下人防洞内空气中氧及其子体浓度.调查结果分析表明,氡及其子体浓度分布,近似服从于对数正态.福建省室内、室外空气中氡浓度几何均值分别为51.8Bq·M^-3与始48.7Bq·M^-3,氡子体a潜能浓度几何均值分刖为13.5×10^-8J·M^-3与11.0×10^-3·M^-3;平衡因子均值分别为0.49与0.53.全省90%住宅内平衡当量氡浓度在75Bq·M^-3以下,在100Bq·M^-3.以上的占3.0‰人防洞内氡子体.潜能浓度变化范周在6.74～840×10^-8J·m.福州地区大部分人防洞内平衡当量氡浓度在200Bq·m^-3以上.全省室内外氡水平地理分布可划为五个区.内地高于沿海,最高水平区域在西南部(即第五区),氡子体a潜能浓度几何均值达54.1×10^-8J·M^-3.全省居民受到室内外氡子体年均暴露量为0.36WLM,所致公众年均有效剂量当量为2.30mSv.     

湖南A铀矿氡和氡子体及矿工肺癌

本文分析了湖南A铀矿井下氡子体对矿工的危害。早年井下氡和氡子体浓度超过限值20多倍.自建矿至1985年底, 主要工种的氡子体累积暴露量平均200WLM。观察2149名1971年前下井老工人, 1970～1985(15年)肺癌死亡11例, 肺癌粗死亡率35.14×10^-5, 特异死亡率24.07×10^-5, SMR=3.17。肺癌平均井下工龄18.5年。肺癌绝对危险系数5.58×lO^-6人年·wLM^-3, 特异相对危险系数5.03×l0^-2WLM^-1。剂量效应分析表明, 肺癌危硷随氡子体累积暴露量增加而增高。     

青海省环境中氡及其子体浓度所致居民内照射剂量

本文对青藏高嫌北部的青海省室内外氡-222及其子体进行了测量。采用闪烁法测氡浓度, 托马斯三段法测氡子体α潜能浓度。测量了162个居室和161个室外的氡及其子体浓度。全省室内外氡的平均浓度分别为：20.94Bq·m^-3和8.01mq·m^-3。     

我国阳江高本底地区居民吸入氡、氧及其子体的年有效剂量当量

我国阳江高本底地区由于地丧中含有弛居石矿物而茛辐射本底有所增高。测定表明: 室内、外空气出平均²²²Rn浓度分别为31.8和16.4Bqm^-3, 为对照地区的2.9和1.5倍, 平均²²²Rn浓度分别为167.5和18.1Bqm^-3, 为对照地区的9.6和1.8倍; 室内、外空气中平均²²²Rn子体α潜能浓度分别为0.1积0.907μJm^-3, 为对照地区的2.6和2.2倍, 平均²¹²Pb÷²¹²Biα潜能浓度分别为0.255和0.053μJm^-3, 为对照地区的3.7和2.7倍。阳江高率底地区居民吸入²²²Rn、²²²Rn及其子体年平均有效剂量当量为2.8mSv, 约为对黑地区和全球正常本底地区的3倍, 其中10.5%来自²²⁰Rn及其子体。     

矿工体内210Po和210Pb含量及其与氡子体累积暴露量的关系

调查云南某公司所属矿山矿工肺癌病因时发现,矿工体内²¹⁰Po、²¹⁰Pb含量.明显地高于地面和其他地区人群.本文测定了矿工和对照组尿、头发、肺组织和患肺癌矿工手术时切除的肋骨中²¹⁰Po、²¹⁰Pb含量.发现矿工骨中²¹⁰Pb含量与根据空气氡子体浓度求得的矿工累积暴露量呈幂函数关系.其相关系数为0.75(P<0.001).     

江苏省环境氡及其子体浓度与所致居民内照射剂量估算

本文报道了江苏省室内、外空气中氡及其子体旅度水平与所致居民内照射剂量的估算结果。全省室内外氡及其子体α潜能浓度近似服从对数正态分布。室内外样品氡浓度的几何均值分别为13Bq·m^-3和9.9Bq·m^-3, 氧子体α潜能浓度的几何均值分别是3.4×10^-8J·m^-3和2.4×10^-8J·M^-3, 平衡因子F为0.42和0.49。因吸入氡子体所致居民人均年有效剂量当量为0.64mSv。     

辽宁省地下建筑物内氡及其子体水平调查

本文描述辽宁地下建筑物内氡及其子体浓度的调查结果,估算了地下建筑物内氡及其子体所致工作人员的剂量.用双滤膜法测氡,Thomas法法测氡子体.共测量42个单位的地下建筑物,计187个样点.氡浓度符合对数正态分布.62%的样点平衡当量浓度(EEC)小于50Bq·m^-3,11%的样点大于200Bq·m^-3(EEC).其浓度的几何均值为74.1Bq·m^-3,几何标准差为3.2.算术均值为168.0 Bq·m^-3,标准差为435.0.氡子体印的几何和算术均值分别为10.0和24.6mWL,几何和算术标准差分别为3.9和43.3.平衡因子为0.53±0.25.剂量估算结果表明,有三分之一的地下建筑物所致年有效剂量当量超过5mSv.讨论了有关限制与防护问题.     

宁夏回族自治区环境氡水平及其所致公众肺部剂量

本文用闪烁法和Thomas三最法测量了宁夏全区房屋178间,其室内氡浓度算术均值为21.3Bq·m^-3(几何均值为16.8Bq·m^-3,下同)氡子体α潜能浓度为2.8(2.3)mWI, F值为0.48(0.43).全区室外测点83个,氡浓度均值为13.7(11.0)Bq·^-3,氡子体a潜能浓度为2.4(1.9)mWL; F值为0.64(0.61).室内、外氡及其子体浓度遵从对数正态分布规律。用人口加权值估算出宁夏居民人均年有效剂量当量算术均值为1.06mSv, 几何均值为0.90mSv.     

湖北省不同类型地下建筑物空气中的氡水平

本文报道了湖北地区不同类型地下建筑物内²²²Rn及其子体的测量结果,估算了工作人员受照剂量,对通风、季节等影响浓度变化的因素进行了初步探讨。据33得132个测点的结果表明.氡及氡子体浓度呈对数正态分布,两者的几何均值分别为77.6Bq·m^-3和3.08×10^-7J·m^-3(14.8mWL),平衡因子为0.58±0.20。工作人员由于吸人氡子体造成的年有效剂量当量为1.91mSv,高出地面居民158%。     

人体中的镭-226、镭-228、钋-210、铅-210

本文报道了广东阳江高本底地区6名、对照地区8名人尸体的骨²²⁶Ra、²²⁶Ra的浓度以及部分居民内脏器官中。²¹⁰Po、²¹⁰Pb的浓度。结果轰明阳江高本底地区和对照地区居民骨镭-226、镭-228的浓度分别为29.9pCi/kg, 26.9pCi/kgl 8.7pCi/kg, 8.2pCi/kg.由此估算出阳江高本底地区屠民骨中²²⁶Ra、²²⁸Ra的负薄璧及对骨衬、骨髓所产生的剂量当量分别为对照地区民民的3.4倍, 3.3倍。两地区居民内脏器官中^{210Po、210Pb的测定分析铡数较少但仍看出, 高本底地区均明显高于对照地区.}     

Rapid synthesis and in vitro and in vivo evaluation of folic acid derivatives labeled with fluorine-18 for PET imaging of folate receptor-positive tumors

In an attempt to visualize folate receptors that overexpress on many cancers, [¹⁸F]-fluorobenzene and pyridinecarbohydrazide-folate/methotrexate conjugates ([¹⁸F]-1, [¹⁸F]-2-folates and [¹⁸F]-8, [¹⁸F]-9-MTXs) were synthesized by the nucleophilic displacement reactions using ethyl-trimethylammonium-benzoate and pyridinecarboxylate precursors. The intermediates ethyl [¹⁸F]-fluorinated benzene and pyridine esters were reacted with hydrazine to produce the [¹⁸F]-fluorobenzene and pyridinecarbohydrazides, followed by coupling with N-hydroxysuccinimide-folate/MTX. Radiochemical yields were greater than 80% (decay corrected), with total synthesis time of less than 45 min. Radiochemical purities were always greater than 97% without high-performance liquid chromatography purification. These synthetic approaches hold considerable promise as rapid and simple method for the radiofluorination of folate derivatives with high radiochemical yield in short synthesis time. In vitro tests on KB cell line showed that significant amount of the radioconjugates were associated with cell fractions, and in vivo characterization in normal Balb/c mice revealed rapid blood clearance of these radioconjugates with excretion predominantly by the urinary and partially by the hepatobiliary systems. Biodistribution studies in nude mice bearing human KB cell line xenografts demonstrated significant tumor uptake and favorable biodistribution profile for [¹⁸F]-2-folate over the other conjugates. The uptake in the tumors was blocked by excess coinjection of folic acid, suggesting a receptor-mediated process. Micro-positron emission tomography images of nude mice bearing human KB cell line xenografts confirmed these observations. These results demonstrate that [¹⁸F]-2-folate may be useful as molecular probe for detecting and staging of folate receptor-positive cancers, such as ovarian cancer and their metastasis as well as monitoring tumor response to treatment.     

Rapid determination of Sr impurities in freshly “generator eluted” Y for radiopharmaceutical preparation

⁹⁰Y is one of the most useful radionuclides for radioimmunotherapeutic applications and has a half-life (t_1/2=64.14 h) suitable for most therapeutic applications, beta particles of high energy and decays to a stable daughter. It is significant that ⁹⁰Y is available conveniently and inexpensively from a radionuclide “generator” by decay of its parent, ⁹⁰Sr. Nevertheless, current and planned clinical applications with [⁹⁰Y] labelled compounds employ activity levels that cannot be readily obtained from an in-house generator, but from commercial sources. We have evaluated Eichrom's Sr-resin, either as an “in-house” generator or as a fast QC method for analysis of ⁹⁰Y solutions.In particular, for the development as a generator, we investigated the percentage of the radio-Sr in the first 8 M HNO₃ eluate: in this fraction the concentration of ⁹⁰Sr must be smaller than 10⁻⁵% (recommendations of the International Commission on Radiological Protection). For evaluation as a rapid QC method, we analyzed the concentration of ⁹⁰Y in all the fractions containing “only” radio-Sr: ⁹⁰Y should not be present in these eluates. After the collection of β⁻ and γ spectra and analysis of them, we concluded that commercial Sr-resin minicolumn cannot give us the results expected; we developed an in-house system loaded with 4 mL of Sr-resin which gave better results as a generator and a rapid QC method.     

226Ra 228Ra 210Pb和210Po在水生生物及食物链中转移规律的探讨

目的 为了解天然放射性核素²²⁶Ra、²²⁸Ra、²¹⁰Pb与²¹⁰Po在水生物及食物链中转移和蓄积情况。方法 定点采集养殖水产品及栖息环境中水与底质沉积物, 按不同的实验需要, 每个鲜样分别剥取肉, 骨(壳),鳞片和胃肠。烹饪样品, 洗净、称重、清炖, 熟后分离出骨(壳),余为食物。样品分别测定²²⁶Ra、²²⁸Ra、²¹⁰Pb和²¹⁰Po含量。数据按统计学要求处理, 配对数据, 作了配对显着性检验。结果 ²²⁶Ra、²²⁸Ra和²¹⁰Pb主要沉积于骨(壳)中, 浓集系数为10²～10³,肉中为10⁰～10².²¹⁰Po主要蓄积在水生物胃肠中, 浓集系数在10²～10⁴,鱼类胃肠与贝类肉中可达10⁴.水产食品烹饪加工过程²²⁶Ra、²²⁸Ra和²¹⁰Pb在食物链中转移不明显, 经配对显着性检验, 差异无显着性(P0.05);然而210Po在淡水鱼类和虾类中转移是明显的, 肉配对检验有非常显着性差别(P<0.01).结论水生物对²²⁶Ra、²²⁸Ra、²¹⁰Pb和²¹⁰Po有很强浓集能力。     

Molecular structures involved in 67Ga and 59Fe binding by placenta and tumors

The binding of ⁶⁷Ga and ⁵⁹Fe by placenta and tumors was compared. After sonification, about 50% of the total radioactivity was present in the insoluble fraction consisting of heavy subcellular particles (mitochondria, fragments of membranes, nuclei, etc.) and known to be rich in lipo- and glycoproteins. Heat denaturation and gel filtration were used to study transferrin and ferritin distribution in the supernatant. The differences between ⁵⁹Fe and ⁶⁷Ga uptake in this supernatant seemed to indicate that the transferrin-ferritin system plays a less important role in ⁶⁷Ga binding than in ⁵⁹Fe binding.     

Radiobiological Issues in the Anomalous Enhanced Effect of Low-dose-rate Fission-spectrum Neutrons: Reply to Letter to the Editor by G. W. Barendsen

Summary

The influence of diet or its ingredients on ¹⁴¹Ce absorption and retention was investigated in six-day-old rats. Animals were fed over 8 h with cow's milk, rat diet or a mixture of rat diet ingredients (fish meal, sunfiower meal, alfalfa, cane molasses and premix) labelled with ¹⁴¹Ce. Whole-body radioactivity was determined in a double crystal scintillation counter every 24 h over a six-day period. Gut, liver, kidney and femur retention and cerium distribution in the gut was determined at the end of the experiment. Compared to milk diet, administration of rat diet or ingredients caused respectively 3 and 7·5 times lower whole body retention. Carcass retention was reduced by rat diet or ingredients 2–3 times and intestinal retention 3 and 8 times respectively. Irrespective of the dietary treatment the main site of cerium intestinal retention was the ileum. Our present results indicate that some compounds of rat diet might be considered as a means of reducing cerium absorption and intestinal retention in the very young.     

Pre-therapeutic dosimetry and biodistribution of 86Y-DOTA-Phe1-Tyr3-octreotide versus 111In-pentetreotide in patients with advanced neuroendocrine tumours

Purpose For the internal radiotherapy of neuroendocrine tumours, the somatostatin analogue DOTATOC labelled with ⁹⁰Y is frequently used [⁹⁰Y-DOTA-Phe¹-Tyr³-octreotide (SMT487-OctreoTher)]. Radiation exposure to the kidneys is critical in this therapy as it may result in renal failure. The aim of this study was to compare cumulative organ and tumour doses based upon dosimetric data acquired with the chemically identical ⁸⁶Y-DOTA-Phe¹-Tyr³-octreotide (considered as the gold standard) and the commercially available ¹¹¹In-pentetreotide.Methods The cumulative organ and tumour doses for the therapeutic administration of 13.32 GBq ⁹⁰Y-DOTA-Phe¹-Tyr³-octreotide (three cycles, each of 4.44 GBq) were estimated based on the MIRD concept (MIRDOSE 3.1 and IMEDOSE). Patients with a cumulative kidney dose exceeding 27 Gy had to be excluded from subsequent therapy with ⁹⁰Y-DOTA-Phe¹-Tyr³-octreotide, in accordance with the directives of the German radiation protection authorities.Results The range of doses (mGy/MBq ⁹⁰Y-DOTA-Phe¹-Tyr³-octreotide) for kidneys, spleen, liver and tumour masses was 0.6–2.8, 1.5–4.2, 0.3–1.3 and 2.1–29.5 (⁸⁶Y-DOTA-Phe¹-Tyr³-octreotide), respectively, versus 1.3–3.0, 1.8–4.4, 0.2–0.8 and 1.4–19.7 (¹¹¹In-pentetreotide), with wide inter-subject variability. Despite renal protection with amino acid infusions, estimated cumulative kidney doses in two patients exceeded 27 Gy.Conclusion Compared with ⁸⁶Y-DOTA-Phe¹-Tyr³-octreotide, dosimetry with ¹¹¹In-pentetreotide overestimated doses to kidneys and spleen, whereas the radiation dose to the tumour-free liver was underestimated. However, both dosimetric approaches detected the two patients with an exceptionally high radiation burden to the kidneys that carried a potential risk of renal failure following radionuclide therapy.     

Value of 111In-DOTA-lanreotide and 111In-DOTA-DPhe1-Tyr3-octreotide in differentiated thyroid cancer: results of in vitro binding studies and in vivo comparison with 18F-FDG PET

Purpose Radioiodine-negative thyroid cancer presents diagnostic and therapeutic difficulties, warranting the implementation of new imaging and treatment strategies. The purpose of this study was twofold. First, we investigated in vitro the binding characteristics of ¹¹¹In-DOTA-lanreotide (¹¹¹In-DOTA-LAN) and ¹¹¹In-DOTA-DPhe¹-Tyr³-octreotide (¹¹¹In-DOTA-TOC) to cells derived from differentiated thyroid cancer (DTC). Second, we evaluated the value of somatostatin receptor (SSTR) scintigraphy with these radioligands, as compared with ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET), for the detection of tumour lesions in DTC patients.Methods Binding of ¹¹¹In-DOTA-LAN and ¹¹¹In-DOTA-TOC to cells isolated from surgically removed thyroid tissue was evaluated in vitro by performing saturation and displacement studies. Eighteen DTC patients with elevated thyroglobulin (12 radioiodine-negative, six radioiodine-positive) were investigated with ¹¹¹In-DOTA-LAN, ¹¹¹In-DOTA-TOC and ¹⁸F-FDG PET scans.Results Large numbers of SSTR binding sites for ¹¹¹In-DOTA-LAN and ¹¹¹In-DOTA-TOC were found on the cells investigated. Both SSTR radioligands exhibited a high binding affinity for these SSTR binding sites. ¹¹¹In-DOTA-LAN and ¹¹¹In-DOTA-TOC scintigraphy detected 37 and 33 lesions, respectively, in 17 (94%) patients each, whereas ¹⁸F-FDG PET revealed 30 lesions in 15 (83%) patients. Uptake of both SSTR radioligands was found in several radioiodine-negative sites. No striking differences in lesion imaging by ¹¹¹In-DOTA-LAN and ¹¹¹In-DOTA-TOC were found. In both radioiodine-negative and radioiodine-positive patients, more lesions were SSTR-positive/¹⁸F-FDG-negative than were ¹⁸F-FDG-positive/SSTR-negative.Conclusion Adding a SSTR scan with these radioligands to the diagnostic work-up increases the diagnostic capacity in DTC, and should be considered particularly in radioiodine-negative patients with elevated thyroglobulin levels.These studies were supported in part by the Austrian National Bank (Anniversary Foundation, Projects No. 7487 and 8185) and by a Foundation of the Mayor of the City of Vienna.     

<Superscript>99m</Superscript>Tc-HYNIC octreotide in neuroblastoma

Disease status assessment of neuroblastoma patients requires computed tomography (or magnetic resonance imaging), bone scan, metaiodobenzylguanidine (MIBG) scan, bone marrow tests, and urine catecholamine measurements. There is no clinical experience concerning the evaluation of these patients by means of technetium-99m (^99mTc)-somatostatin analog scintigraphy. Furthermore, these radiopharmaceuticals are promising imaging agents owing to their lower cost, availability, dosimetry, and ease of preparation. An 8-year-old boy already diagnosed with stage-IV neuroblastoma received chemotherapy. In the follow-up, after obtaining the parents’ informed consent, iodin 131 (¹³¹I)-MIBG and ^99mTc-6-hydrazinopyridine-3-carboxylic acid (HYNIC)-octreotide scans were done on separate days to evaluate tumor extension. Even as the ¹³¹I-IBG scan showed mild diffuse uptake in the projection of both lung hili, the ^99mTc-HYNIC-octreotide scan showed multiple axial and appendicular bone uptakes and paravertebral, abdominal, mediastinal, and supraclavicular ganglionar uptakes. The ^99mTc-HYNIC-octreotide showed much more lesion extension than the ¹³¹I-MIBG. Therefore, ^99mTc-HYNIC-octreotide may be a promising radiopharmaceutical for the evaluation of neuroblastoma patients. This finding justifies the pre liminary evaluation of this tracer in the context of a clinical trial.     

Comparison of [18F]FDG-PET and L-3[123I]-iodo-alpha-methyl tyrosine (I-123 IMT)-SPECT in primary lung cancer

OBJECTIVE: The aim of this study was to evaluate L-3[123I]-iodo-alpha-methyl tyrosine (IMT)-SPECT and FDG-PET in pulmonary lesions suspected to be lung cancer. METHODS: Whole body PET (measured transmission corrected emission scans) was performed 45 minutes after i.v. injection of 222-370 MBq (6-10 mCi) 18F-FDG on a Siemens PET scanner (ECAT EXACT 47) including 5-6 bed positions. 123I-IMT-SPECT (chest) was performed after injection of 370 MBq (10 mCi) with a dual head camera (Picker Prism 2000) and commercially available reconstruction algorithms. Ten patients (6 male and 4 female) with suspected lung cancer were investigated. The results were compared to histological findings after surgery or bronchoscopic biopsies and CT. RESULTS: 123I-IMT-SPECT and FDG-PET were able to detect all 9 cases of lung cancer (1-8 cm in diameter). One case was true negative. Both imaging methods were true positive with respect to mediastinal lymph node metastases in one patient. The tumor/background ratio was higher with PET (8.20 vs. 2.84). CONCLUSION: Despite the limited number of patients it may be concluded that IMT-SPECT as well as FDG-PET are suited to correctly diagnose lung cancer. Nevertheless, FDG-PET, if available, seems to be better suited because of the higher tumor/background ratio and better resolution.