144Ce诱发大鼠肿瘤的实验研究

本文报道了¹⁴⁴Ce一次皮下注入诱发大鼠肺癌的实验结果。Wistar大鼠随机分为三组,注入后一年I组注八量14.8×10⁵Bq)肿瘤的发生率为40%(20/50); Ⅱ组(注人量7.4×10⁵Bq)为34%(17/50),而对照组仅为2%(1/50).     

黑龙江省食品和水中天然放射性水平及对居民所致内剂量估算

本文介绍了黑龙江省食品和水中的天然放射性比活度及其对居民所致内照射剂量。测定了23种食品、自来水井水和松花江水中的放射性核素的比活度,²³⁸U、²³⁴U、²³²Th、²²⁶Pa及⁴⁰K、的平均比活度分别是:植物性食品为3.6×10^-2Bq/kg、3.6×10^-2Bq/kg、1.5×10^-2Bq/kg、9.6×10^-2Bq/kg和86Bq/kg;动物性食品为2.6×10^-2Bq/kg、2.6×10^-2Bq/kg、1.0×10^-2Bq/kg、4.6×10^-2Bq/kg、65Bq/kg;饮用水为2.4×10^-2Bq/L、2.4×10^-2Bq/L、2.0×10^-4Bq/L、1.2×10^-2Bq/L、4.6×10^-2Bq/L;松花江水为6.2×10^-3Bq/L、6.2×10^-3Bq/L、3.0×10^-4Bq/L、1.1×10^-2Bq/L、2.7×10^-2Bq/L。我省成年男子对²³⁸U、²³⁴U、²³²Th和²²⁶Ra的人口加权年摄入量分别我:36Bq、36Bq、5.2Bq、65Bq。由这四种核素所致人口加权年有效待积剂量当量是28μSv。     

放射性核素内照射诱发大鼠外周血淋巴细胞HPRT基因位点突变与染色体畸变的研究

目的 阐明放射性核素内照射诱发外周血淋巴细胞HPRT基因位点突变的剂量效应关系, 并与染色体畸变剂量效应关系进行比较。方法 给动物尾静脉注射放射性核素, 注射量为0.5ml/100g体重。剂量效应关系组动物注射活度为3.64×10⁵Bq/ml, 于注射后1、3、6和9d心脏穿刺取血。剂量率效应关系组动物注射活度分别为3.64×10⁵、1.82×10⁵、0.91×10⁵和0.445×10⁵Bq/ml, 于注射后3、6.7、17和42d心脏穿刺取血。应用多核细胞法及胞质分裂阻断法(CBMN)和常规染色体畸变分析法检测HPRT基因位点突变率和染色体畸变率。用计算机拟合剂量效应关系和剂量率效应关系函数。结果 淋巴细胞HPRT基因位点突变率不仅随内照射剂量和剂量率增加而增加, 呈现出良好的正相关, 而且与染色体畸变亦呈现出较好的相关性。结论 辐射诱发HPRT基因位点突变有可能成为有效的辐射生物剂量计。     

天津市食品和饮水中天然放射性核素水平及所致居民内剂量

本文总结了天津市食品和改水中天然放射性核索U、²³²Th、²²⁶Ra、⁴⁰K的水平,及通过 食品和饮水摄入这些该素所致居民年待积有效剂量当量。调查结果表明:食品中U含量为(0.6～11.2)×10^-2Bq/kg;²³²Th为(0.1～5.7)×10^-2Bq/kg ²²⁶Ra为(0.5～6.6)×10^-2Bq/kg;⁴⁰K为25～96.8Bq/kg饮水中U含量为(1.7～2.6)×10^-2Bq/L;²³²Th为(0.04～0.1)×10^-2Bq/L;²²⁶Ra为(0.1～0.3)×10^-2Bq/L。我市居民由饮食摄入天然放射性核素U、²³²Th、²³⁶Ra所致年待积有效剂量当量分别为:1.8μSv/a、4.1μSv/a、2.6μSv/a。     

低剂量率60Coγ线长期慢性照射和一次急性照射雄性小鼠诱发显性致死突变的研究

每天以2.02、3.84、7.68和13.03拉德γ线慢性照射雄性小白鼠,诱发的显性致死突变率均高于对照组。其中7.68和13.03拉德组的诱发率与累积剂量线性相关,分别为2.19×10^-4/拉德和2.63×10^-4/拉德。以114拉德/分剂量率一次照射小白鼠精子和精细胞的诱发率均与照射剂量呈线性相关,分别为0.75×10^-3/拉德和1.49×10^-3/拉德。慢性照射和急性照射精原细胞诱发的显性致死突变与累积剂量均无相关性。     

大气中铅-210和钋-210浓度及影响因素

使用²⁰⁰Po示踪α谱法测定了济南,泰安等地大气中²¹⁰Pb和²¹⁰Po的放射性浓度,研究了它们随降雨等影响因素而变化的规律。济南大气中²¹⁰Pb浓度范围为0.20～4.58×10^-8Bq?m^-8,几何平均值为1.35×10^-8Bq?m^-8;²¹⁰Po浓度范围为0.013～2.82×10^-8Bq?m^-8,几何平均值为0.42×10^-8Bq?m^-8,该测值高于现已报道的多数国家和地区。     

氚水所致LACA小鼠脾脏溶血空斑的变化

本文选用对辐射较为敏感的抗体生成细胞检测了氚水(HTO)内照射5天后LACA小鼠脾脏溶血空斑(PFC)数量的变化。当初始注入HTO的量分别为5.673×10⁴,1.134×10⁵,2.274×10⁵和4.538×10⁵Bq/g体重时,5天内脾脏累积吸收剂量分别为1.0、2.0、4.0,8.0Gy。结果表明:(1)1.0GyHTO内照射即可使PFC数量发生明显减少。(2)随着HTO剂量的增加,PFC数量呈幂函数降低,可拟合为如下关系式:Y=exp(5.34829-0.234899X-0.02176513X²)。(8)PFC数量的降低似与前列腺素E的合成无关。(4)小鼠脾重在几个剂量组间无显著性差异。     

浙江省食品和饮水中U、Th、226Ra和40K的水平及对居民所致内照射剂量的评价

本文报道了浙江省19种主要食品和饮水中天然放射性核素U、Th、²²⁶Ra和⁴⁰K的调查结果,并估算了由此所致居民的内照射剂量。通过本次调查基本上摸清了全省13个地区的主要食品和8大水系中天然放射性核素的水平和分布。结果表明,食品中U、Th、²²⁶Ra和⁴⁰K的比活度分别为:(0.05～113)×10^-2,(0.05～10.8)×10^-2、(1.9～290)×10^-2和19.3～533Bq·Kg^-1;在水中的放射性活度分别是(1.40～24.9)×10^-3、(0.14～0.41)×10^-3、(3.7～13.0)×10^-3和(19.3～525)×10^-3Bq·L^-1,U、Th、²²⁶Ra的人均年摄入量分别为:17.0、3.9、44.4Bq。²³⁸U、²³⁴U、²³²Th、²²⁶Ra的年有效剂量当量分别为:0.47、0.65、2.9、13.8(×10^-6Sv·a^-1),合计为17.8×10^-6Sv·a^-1。同时,我们还估算了上述核素致本省居民靶器官的年吸收剂量。     

碘-131治疗患者污染的、监测

本工作测定了服碘-131治疗的甲癌患者在呼出气、唾液,汗中的碘-131的最大排出率,并监测了患者的内衣、筷子、牙刷等物品的表面污染。患者呼出气中碘-13l的最大排出牢为1.0×10^-6/小时,服用剂量;汗为3.O×10^-5/小时,服用少量唾液为2.3×10^-4毫升,服用剂量。本文对碘-131治疗甲癌和甲亢患者的医学防护和管理问题进行了讨论。     

贵州省部分矿山放射性水平的评价

目的 调查和评价贵州省铝、锰、锑、磷、汞等部分矿山放射性水平。方法 对矿区氡气、钍气浓度进行累积1年的现场检测;采集矿石、矿山周围土壤进行放射性核素分析;对矿区γ辐射水平进行测量;对矿山渗透水进行总α、总β测量。结果 某铝矿山春、夏两季井下氡浓度水平为626.0～3866 Bq m³,秋、冬两季为38.9～655.0 Bq m³,全年平均值为1374 Bq m³;春、夏两季井下钍浓度水平为626.0～4834 Bq m³,秋、冬两季为40.9～344.0 Bq m³,全年平均值为1221 Bq m³。其余矿山均低于此水平。矿石放射性核素²²⁶Ra为6.9～511.9 Bq/kg、²³²Th为1.4～536.7 Bq/kg、⁴⁰K为<17.5～433.7 Bq/kg。γ外照射最高的为铝矿,平均值(87.0±8.1)×10^-8 Gy/h,最低的为锑矿,平均值(6.0±1.9)×10^-8 Gy/h。矿山井下水总α为小于探测下限～17.5(×10^-2Bq/L),总β为小于探测下限～37.4(×10^-2Bq/L)。结论 此次调查的部分矿山,大多采用机械和自然相结合的通风方式,通风情况较好。但铝矿井下的氡、钍浓度水平明显高于井外,全年平均值分别是井外的78倍和15倍;铝矿的γ外照射平均值(87.0±8.1)×10^-8 Gy/h,也明显高于贵州省γ天然辐射平均值(13.3×10^-8 Gy/h)。这将对该矿的矿工增加一定的附加剂量。     

131I大鼠甲状腺致癌作用的病理学研究

本文报道用雄性Wistar大鼠409只,腹腔分别注射¹³¹I 52.4、40.0、26.2; 12.5和2.5μCI／只,两年的观察结果。五个剂量组甲状腺吸收剂量分别为164、125、82、39和7.8Gy.12个月发生甲状腺良性瘤,观察到24个月时,39Gy以上各剂量组主要表现为耳状腺退行性变和良性癌生成;而7.8Gy剂量组甲状腺恶性瘤发生率达45.8%。¹³¹I诱发大鼠甲状腺良性肿瘤以滤泡性腺癌为主,其次是乳头状腺癌,恶性瘤以乳头状腺癌和混合癌为主,甲状腺肿瘤的发生与¹³¹I对甲状腺滤泡上皮细胞损伤、修复;在甲状腺轴内分泌紊乱(T₄降低、TSH升高)情况下,TSH反复刺激损伤的甲状腺上皮细胞有关。     

Myocardial sympathetic innervation in the athlete's sinus bradycardia: Is there selective inferior myocardial wall denervation?

BACKGROUND: Sinus bradycardia in trained athletes is predominantly a manifestation of increased vagal tone, but it is not known whether an alteration in the cardiac sympathetic system can contribute to blunted chronotropic response. This study assessed the integrity of the sympathetic system in trained athletes with sinus bradycardia by means of the iodine-123-metaiodobenzylguanidine (123I-MIBG) procedure. METHODS AND RESULTS: Fourteen athletes with sinus bradycardia and 8 athletes with a normal heart rate were explored by means of planar and single photon emission computed tomography MIBG studies. The heart/mediastinum ratio, regional myocardial distribution, and percent of regional myocardial MIBG uptake were evaluated. The heart/mediastinum ratio in athletes with sinus bradycardia was 1.87+/-0.10, and in athletes with a normal heart rate, the heart/mediastinum ratio was 1.86+/-0.16 (P = not significant). In athletes with sinus bradycardia, the regional distribution of MIBG showed an inferior and apical uptake defect in 8 athletes, an inferior, apical, and septal defect in 3 athletes, an inferior defect in 1 athlete, and normal distribution in 2 athletes (14%). In athletes with a normal heart rate, the regional distribution of MIBG showed an apical uptake defect in 3 athletes and normal distribution in 5 athletes (63%). The percent of regional MIBG uptake in the inferior region was significantly reduced in athletes with sinus bradycardia (44%+/-13% vs. 72%+/-11%, P<.01). CONCLUSION: These results show severely reduced myocardial MIBG distribution in the inferior region in athletes with sinus bradycardia, suggesting selective inferior myocardial wall sympathetic denervation, which may be related to increased vagal tone.     

Effects of Irradiation on the Mediterranean Meal Moth,Ephestia Kuehniella Zeller,Cultured on 89Sr-spiked Food

Summary

Ephestia kuehniella Zeller was cultured on corn-meal spiked with ⁸⁹Sr at concentrations of 0, 0·1, 0·3, 1·0, 3·0 and 5·0 µc/g of food.

As the environmental radiation was increased, the adults which were subjected throughout their life-cycle produced progressively fewer progeny.

5·0 µc ⁸⁹Sr/g food approaches the critical level which will inhibit population development.

Life-span of the adults was not influenced by the experimental conditions.

Delayed development occurred at all isotopic concentrations employed.

The radiostrontium-content of females at the end of their life-cycle was half that of males. Twenty-four hours after eclosion, the radioactivity of the female moth was equal to, or greater than, that of corresponding males. Reproductive metabolism is offered in explanation.

At the two highest culture levels (3 and 5 µc ⁸⁹Sr/g), the increased number of males (homogametic sex) over females (heterogametic sex) is consistent with the radiation genetic effect of induced recessive lethals. No selective radiation effect upon the sexual capacity of gametes of the F₁ was indicated, since the subsequent F₂ sex ratio was 1 : 1.     

Detection of coronary artery disease by iodine-123-labeled iodophenyl-9-methyl pentadecanoic acid SPECT: Comparison with thallium-201 and iodine-123 BMIPP SPECT

To evaluate the ability to detect coronary artery disease (CAD) with a new iodine-123 labeled branched fatty acid analog, iodophenyl-9-methyl pentadecanoic acid (9MPA), we performed 9MPA, iodine-123 BMIPP and thallium-201 SPECT in patients with CAD. Twenty-four patients (11 with effort angina and 13 with myocardial infarction) were studied. In all patients, 9MPA SPECT was obtained at 15 min after injection. Twenty-three patients underwent stress-redistribution 201Tl SPECT and 9 patients also underwent BMIPP myocardial fatty acid imaging. The regional uptakes of 9MPA, BMIPP and 201Tl were scored semiquantitatively and the segmental agreements were compared among them. In the segment-to-segment comparison, 9MPA showed reduced activity in comparison to stress-redistribution 201Tl imaging. The defect score of 9MPA was significantly greater than that of redistribution 201Tl images (p < 0.001). In addition, segmental 9MPA uptake was lower than BMIPP and its defect score was significantly greater than that of BMIPP (p < 0.05). When coronary angiography was used as the criterion, 9MPA showed higher sensitivity and lower specificity than stress-redistribution 201Tl (p < 0.01). In conclusion, fatty acid metabolic imaging with 9MPA is a sensitive but nonspecific detector of CAD.     

Clinical usefulness of iodine-123-MIBG scintigraphy for patients with neuroblastoma detected by a mass screening survey

The purpose of this study was to evaluate the usefulness in a clinical setting of iodine-123-metaiodobenzylguanidine (123I-MIBG) scintigraphy, planar and single photon emission computed tomography (SPECT) images, in patients with neuroblastoma as detected by a mass screening survey. METHODS: 123I-MIBG planar whole body images, and regional SPECT images of patients with neuroblastoma in 51 studies were reviewed. They were all detected by a mass screening survey performed in the 6th month after birth using vanil mandelic acid (VMA), and homovanillic acid (HVA) and the neuroblastoma had been confirmed by surgery. Scintigraphy was performed 24 hours after injection of 111 MBq of 123I-MIBG. We assessed the accuracy of the planar whole body images in order to demonstrate the extent of the lesion and the correlation between the degree and extent of the lesions of 123I-MIBG accumulation and clinical staging with tumor markers, such as urinary VMA, urinary HVA, serum neuron specific enolase (NSE) and serum lactate dehydrogenase (LDH). Additionally, we evaluated SPECT how useful supplemental SPECT might be in a clinical setting as compared with planar whole body images. RESULTS: 123I-MIBG planar whole body images revealed all 33 (100%) primary lesions, 4 of the 5 cases (80%) with liver metastasis, 3 of the 13 (23%) with lymph nodes metastasis and 1 of 3 (33%) with bone marrow infiltration. The extent and degree of accumulation correlated with the values of urinary VMA, urinary HVA and serum NSE. SPECT images helped to understand the positional relation in all cases and provided useful additional information for clinical staging in 7 cases. CONCLUSION: 123I-MIBG scintigraphy with planar and SPECT images is useful for evaluating patients with neuroblastoma, following detection by a mass screening survey.     

131I治疗甲状腺功能亢进症的影响因素

甲状腺功能亢进症131I治疗剂量的确定受甲状腺吸碘率、有效半衰期、甲状腺质量、抗甲状腺药物等众多因素影响,131I治疗的预后情况是这些因素共同作用的结果.     

125I放射性粒子组织间植入治疗腮腺癌专家共识(2023年版)

¹²⁵I放射性粒子组织间植入治疗是腮腺癌主要治疗方法之一,具有局部剂量高和周围组织损伤小的特点。放射性粒子治疗效果与剂量、精度密切相关。然而,¹²⁵I放射性粒子在腮腺癌中的应用尚无明确规范,各治疗中心对于放射性粒子治疗的标准不尽相同。为进一步规范腮腺癌近距离放射治疗流程,经国内多位专家反复讨论后达成一致意见,制定本共识。本共识对¹²⁵I放射性粒子组织间植入治疗腮腺癌的适应证与禁忌证、治疗参数、操作流程、技术规范、放射防护、不良反应、随访等给出了规范化建议,可供临床实践参考。     

甲状腺功能状态对131I在人体的内照射剂量估算的影响

我们对服用¹³¹I(Nal¹³¹I)人员进行了15天24小时尿碘分析以及外部放射性计数测量,推算出几种甲状腺功能状态下¹³¹I在人体的分布、滞留和内辐射剂量。结果表明;摄入¹³¹I后甲状腺受到的内辐射剂量与甲状腺摄碘率间呈一元线性函数关系。在此基础上进一步推算了苏州市及其近郊因进 行甲状腺摄碘检查所致的年集体有效剂量当量等指标。     

A new method to estimate rCBF using IMP and SPECT without any blood sampling

We developed and evaluated a method to measure rCBF without any blood sampling by using iodine- 123 IMP and SPECT. An integral of arterial input function, the integral taken from the value 0 to T of the variable Ca(t)dt, can be expressed as TC(T)/CO, where TC(T) is radioactivity delivered to the body in T minutes and CO is cardiac output. If T is acceptably small, rCBF can be determined by means of a microsphere model analysis with IMP as Cb(T)/(TC(T)/CO), where Cb(T) is cerebral radioactivity at T minutes. We derived TC(T) and CO from a chest dynamic scan. The method was applied to 45 patients who underwent rCBF studies (58 studies) with arterial blood sampling (ABS). Data from the chest scan were analyzed in comparison with ABS data in the first 28 studies, and equations for correction yielding an accurate TC(T)/CO were derived. The validity of the proposed method was evaluated in the subsequent 30 studies. The method yielded rCBF (rCBF-test) which agreed well with rCBF obtained by a two-compartment model analysis of dynamic SPECT and ABS data (rCBF-ref) with the mean and SD of differences between rCBF-test and rCBF-ref being 1.0 and 2.7 ml/100 g/min, respectively. In eleven subjects who underwent more than two studies, a percentage change in rCBF-test between the studies also closely approximated that of rCBF-ref (y = 1.11 x + 2.63, r = 0.92). The method can be used with acceptable reliability to measure rCBF without any blood sampling.     

Radioprobing the conformation of DNA in a p53-DNA complex

Abstract

Purpose: The frequency of DNA strand breaks produced by the decay of Auger electron-emitting radionuclides is inversely proportional to the distance of DNA nucleotides from the decay site; and thus is very sensitive to changes in the local conformation of the DNA. Analysis of the frequency of DNA breaks, or radioprobing, gives valuable information about the local DNA structure. More than 10 years ago, we demonstrated the feasibility of radioprobing using a DNA-repressor complex with a known structure. Herein, we used radioprobing to study the conformation of DNA in complex with the tumor suppressor protein 53 (p53). Several structures of p53-DNA complexes have been solved by X-ray crystallography. These structures, obtained with the p53 DNA binding domain, a truncated form, laid the groundwork for understanding p53-DNA interactions and their relation to p53 functions. However, whether all observed stereochemical details are relevant to the native p53-DNA complex remains unclear. A common theme of the crystallographic structures is the lack of significant bending in the central part of the DNA response element. In contrast, gel electrophoresis and electron microscopy data showed strong DNA bending and overtwisting upon binding to the native p53 tetramer.

Methods: To analyze DNA in complex with p53, we incorporated ¹²⁵I-dCTP in two different positions of synthetic duplexes containing the consensus p53-binding site.

Results: The most significant changes in the break frequency distributions were detected close to the center of the binding site, which is consistent with an increase in DNA twisting in this region and local DNA bending and sliding.

Conclusions: Our data confirm the main results of the studies made in solution and lay a foundation for systematic examination of interactions between DNA and native p53 using ¹²⁵I radioprobing.