~(228)镭-铍(a n)源的中子能谱

~(228)Ra从钍工业放射性废料中作为一种付产品而获得。在印度的钍工厂生产中每日最多可回收250毫居里。~(228)Ra是钍放射系(A=4n)的第一个子     

硼中子俘获治疗的加速器中子源7Li(p,n)7Be的中子特性研究

目的 通过研究质子加速器 ⁷Li(p,n)⁷Be 反应的中子特性,为研究和制作适用于硼中子俘获治疗(BNCT)的加速器中子源提供基础数据。方法 加速质子使其轰击Li靶后产生中子;通过金属箔活化法,测量中子与In箔发生阈值反应后放出的γ射线;然后计算出In箔的放射性活度、加速器反应后放出中子的注量和反应的微分截面。结果 质子加速轰击Li靶后,在不同方向产生不同能量和注量的中子。加速器电压分别为3.0、2.8和2.6 MV,出射中子与入射质子束的方向一致时, ⁷Li(p,n)⁷Be 反应的微分截面约为50 mb/mr;夹角为60°时,反应的微分截面减小到30 mb/mr左右。由于部分中子与其他金属原子等发生弹性散射而射向后方,提高了这一范围内In箔的比放射性活度,影响了其微分截面的准确性。结论 用金属箔活化法测定中子简便易行,可同时测得多个方向的中子分布,但需对中子与其他金属弹性散射产生的影响进行进一步的研究; ⁷Li(p,n)⁷Be 反应后发射出的中子经慢化后,能得到适于BNCT治疗的热中子和超热中子;若作为BNCT的中子源,加速器的质子束流需达到10 mA。     

γ谱测定天然水中的~(228)Ra和~(226)Ra

美国环保局(EPA)规定,如果公共饮水中~(228)Ra活性超过3pCi/1,则必须测量~(228)Ra活性。EPA公布的~(228)Ra标准分析方法是萃取和计数~(228)Ra的短寿命子体~(228)Ac,或连续计数纯化后的Ra样中~(228)Ac的增长。~(226)Ra是用射气法,海水中~(228)Ra的测定用~(228)Th增长法。大体积海水中Ra的浓集早先。用Ba(Ra)SO_4共沉淀法,现用镀MnO_2的丙烯酸纤维(锰纤维)浓集。本文用锰纤维筒浓集100～1000升水样中的Ra,再用Ge(Li)γ谱测量天然水中~(228)Ra     

硼中子俘获治疗(BNCT)设备中子束流质量控制检测项分析

目的通过对医院中子照射器(IHNI)的超热中子束流辐射特性参数和剂量学特性参数的检测, 为建立硼中子俘获治疗(BNCT)设备中子束流的质量控制检测方法提供参考。方法通过对比各项检测结果的不确定度与欧洲联合研究中心(EC-JRC)推荐的偏差值, 分析评估相应检测方法的可行性。结果超热中子注量率的不确定度为2.7%;热中子与超热中子注量率比值的不确定度为3.1%;快中子空气比释动能率与超热中子注量率比值的不确定度为9.3%;γ空气比释动能率与超热中子注量率比值的不确定度为8.7%;中子注量率空间分布的不确定度为2.7%;模体内热中子注量率的不确定度为1.8%;模体内中子和γ射线剂量率的不确定度分别为17.1%和4.0%。结论模体内中子剂量率测量结果不确定度高, 需要进一步研究该项检测方法来提高检测结果的准确度;其余检测项测量结果不确定度低, 检测结果准确度预期能满足欧洲联合研究中心的推荐允许偏差值, 检测方法可行。     

(n,p), (n,α) and (n,2n) reaction cross-sections for some isotopes of Zr,Pd, and Cd at 14.8 MeV

The cross-sections for the ⁹⁰Zr(n,p), (n,α) and (n,2n), ⁹¹Zr(n,p), ⁹⁴Zr(n,p), ¹⁰²Pd(n,2n), ¹⁰⁶Pd(n,p), ¹⁰⁸Pd(n,2n), ¹¹⁰Pd(n,2n), ¹⁰⁸Cd(n,2n), ¹¹²Cd(n,2n) and ¹¹⁶Cd(n,2n) reactions at 14.8 MeV were measured by the activation technique. Full experimental details are included. The results are compared with other published values.     

宝石能谱CT(GSI)诊断骨质疏松的应用价值初探

目的探讨宝石能谱CT物质分离技术诊断腰椎骨质疏松的临床应用价值。方法选取2015年9月~2017年10月于青岛市市立医院接受腹部宝石CT能谱检查和DXA检查的患者22例,以L1~L4椎体(88个)作为研究对象,测量L1~L4椎体的HAP(脂)密度值和DXA的骨密度值,以双能X线吸收法(dual-energy X-ray absorptiometry,DXA)作为金标准,参考WHO的诊断标准分组,即T值≤-2.5 SD为骨质疏松组,-1.0~-2.5 SD为骨量减少组,≥-1.0 SD为骨量正常组。应用单因素方差分析对DXA证实的骨质疏松组、骨量减少组和骨量正常组的HAP(脂)密度值进行比较;对HAP(脂)密度与DXA骨密度的相关性行Pearson分析;根据HAP(脂)密度值绘制ROC曲线,探讨宝石能谱CT诊断骨质疏松的最佳阈值。结果骨质疏松组、骨量减少组和骨量正常组之间腰椎HAP(脂)密度均具有统计学差异(P0.001);腰椎HAP(脂)密度与DXA骨密度呈高度正相关(r=0.864,P0.001);当腰椎HAP(脂)密度取116.160mg/cm3为诊断骨质疏松的阈值时,其灵敏度为81%,特异度为88%。结论宝石能谱CT物质分离技术能够反映腰椎骨密度的变化,对骨质疏松诊断具有较高价值。     

中子及γ线辐射对药物的影响(摘要)

用中子(积分通量1×1013)及γ射线(1×104R)照射以注射药为主的72种常用药物,在辐照后48小时测定其感生放射性,并按中华人民共和国药典及生物制品检定规程进行检定。还测定了36种药物的LD50及观察40种药物的主要药理作用,在辐照后3个月时重复检定1次。实验结果表明;在辐照后48小时仅葡萄糖氯化钠注射液及氯化钾注射液感生放射性在10-1μ水平。3个月时全部药物均在本底外水平。 有59种药物在辐照以后其外观、理化性质、含量、毒性、效价(包括类毒素等的免疫力)均与对照药物相似。有明显变化者3种。其中以维生素B12为最。在本实验的辐射剂量范围内,其含量下降与辐照剂量呈明显的负相关及线性关系。麻醉乙醚在辐照后产生了过氧化物;0.1％枸橼酸注射液含量下降均不符合规定的标准。此外尚有硫     

中子活化分析法测量土壤中的~(237)Np

由于~(237)Np含量非常低以及分析的技术困难,有关环境~(237)NP的资料在文献中几乎没有报道。本文讨论了中子活化分析土壤样品中低水平~(237)Np的方法。将2～300克制备好的土壤灰样在迥流烧瓶中用50～80ml浓HCl+浓HNO_3(1:1)浸取两次。样品中加入~(239)Np示踪剂。抽滤浸取液,合并滤液和洗液,滤液中加入盐酸羟胺(0.smol八)和硫酸联胺(0.01mol/L)加热,使Np(Ⅴ)还原为Np(Ⅳ)。用100ml异丙醚震荡萃取两次。水相在电热板上加     

广东高本底地区居民呼出气中(气土)浓度及体内钍-228沉积量的测定

为了估算高本底地区居民和对照地区居民体内钍系核素的沉积量,我们于1980年9月1日至20日列高本底地区的阳江县田畔公社和对照地区的台山县深井公社各20名男性社员进行了呼出气中(气土)浓度的测定,并依此推算出惟内钍-8的沉积量.测定结果是高本底呼出气中平均(气土)浓度为0.56±0.13pCi/升,体内的钍-228的沉积量为100pCi:对照地区呼出气中平均(气土)浓度为0.18+0.04pCi/升,体内的钍-228的沉积量为32pCi。这一结果表明,高本底地区居民体内钍系核素量确实高于对照地区,与以往用其他方法所得出的结论是一致的。     

Measurement of the fission neutron spectrum averaged cross sections for the 95Mo(n,p)95Nb, 92Mo(n, α)89Zr, 90Zr(n, 2n)89Zr and 60Ni(n,p)60Co reactions

The average cross-sections in a fission-type reactor neutron spectrum are determined experimentally for the reactions: ⁹²Mo (n, a) ⁸⁹Zr, ⁹⁰Zr (n, 2n) ⁸⁹Zr and ⁶⁰Ni (n, p) ⁶⁰Co. The determined cross sections are in the ranges of the reported values in literature. A method for determining the cross sections in relative way is introduced. It replaces the cross sections and the nuclear data by a composite nuclear data constant which can be calculated and determined experimentally. It is shown that the uncertainties of determining these constants experimentally are mainly lower than the calculated ones. The consequences of using this constant in neutron activation analysis are briefly discussed.     

α能谱法测定环境水样品中的~(226)Ra

取150mg含镭的钡溶液,蒸干,残渣溶于15～20mL0.05mol CyDTA(pH5.0)中,溶液流过阳离子交换树脂柱(Dowex 50W×8,φ15×100mm),再用20mL 0.05mol CyDTA溶液(pH 5.0)、20mL饱和硼酸溶液(pH8.5)洗柱,最后用100mL 0.05mol的     

Excitation functions of 93Nb(n, 2n) 92mNb, 93Nb(n, α)90m,gY, 139La(n, α)136Cs and 181Ta(n,p)181Hf reactions in the energy range of 12.5–19.6 MeV

Cross sections were measured for the ⁹³Nb(n, 2n) ^92mNb, ⁹³Nb(n, α) ^90m,gY, ¹³⁹La(n, α)¹³⁶Cs and ¹⁸¹Ta(n, p)¹⁸¹Hf reactions in the energy range of 12.5–19.6 MeV. Use was made of the activation technique in combination with high-resolution γ-ray spectroscopy, except for the product ^90gY where radiochemical separation and β⁻ counting were applied. The neutron fluence rates were determined using two independent methods, viz. proton recoil telescope and ²⁷Al(n, α)²⁴Na monitor reaction. An appraisal of the available cross section data for the five investigated processes was carried out. Due to its relatively high importance as a dosimetry reaction an evaluation of the ⁹³Nb(n, 2n) ^92mNb excitation function based on the most recent data is recommended. For the other reactions our measurements furnish an extended data base. A comparison of the experimental data with values calculated from the semi-empirical code THRESH is presented. The code predicts unknown activation cross sections only with partial success.     

探讨腹部CT增强能谱成像碘对HAP(Iodine)HAP(Water)HAP(Fat)密度测量值影响

【摘要】目的：探究碘对比剂对能谱CT基物质成像HAP（Iodine）、HAP（Water）、HAP（Fat）密度测量值的影响,寻找增强扫描中可用于骨密度测量参考的基物质对。方法：回顾性搜集基于BMI行个体化全腹部能谱（GSI）增强扫描患者214例,男135例、女79例,年龄16～85岁,记录每位患者的碘摄入量。临床采用4期（平扫期、动脉期、静脉期、延迟期）GSI扫描,获得图像数据传输到AW4.7工作站,应用GSI后处理软件重组各期的HAP（Iodine）、HAP（Water）、HAP（Fat）基物质图像,测量并记录4期图像中第三腰椎椎体骨松质的HAP（Iodine）、HAP（Water）、HAP（Fat）密度值。采用配对样本t检验分别对HAP（Iodine）、HAP（Water）、HAP（Fat）各期密度测量值进行两两比较;对患者碘摄入量与增强3期HAP（Iodine）密度测量值行Pearson相关分析。结果：4期HAP（Water）、HAP（Fat）值差异均有统计学意义（P＜0.05）,而4期HAP（Iodine）值差异无统计学意义（P＞0.05）,4期HAP（Iodine）值分别为693.49±20.29、693.39±20.30、693.18±20.14、693.19±20.44,单位为2mg/cm3;碘摄入量与增强3期HAP（Iodine）密度测量值均无相关性（P＞0.05）。结论：HAP（Water）、HAP（Fat）测量值受碘对比剂影响较大,而HAP（Iodine）测量值不受碘对比剂影响,4期中HAP（Iodine）测量值趋于稳定。HAP（Iodine）测量值可用作平扫与增强扫描评估骨密度的参考。     

高能中子P(66Mev)Be(49Mev)治疗后病人的晚发反应和并发症

文章收集可供评价的71例按中子治疗方案分组的病人。所有的病人均接受超过20 Gy 的中子根治剂量或生物学相当的混合束。第一组22例,为单纯中子根治放疗。其中19例为头颈部癌,存活的病人中有2例为胰腺癌,1例直肠腺癌。剂量为20～23Gy(除1例27Gy 外),分割次数为8～28次/6周(40～45天)。第二组29例,为光子加中子合并治疗。其中20例先给相对大野的标准疗程的光子治     

能谱CT对COPD胸椎钙(水)密度变化趋势的初步研究

目的探讨能谱CT对慢性阻塞性肺疾病患者胸椎钙(水)密度变化规律的应用价值。方法选取COPD患者61例,按照肺气肿指数分为肺气肿组和非肺气肿组,并设置对照组35例,进行对比研究。结果胸椎钙(水)密度随肺通气功能受损加重而减少;肺气肿组胸椎钙(水)密度均低于非肺气肿组和对照组(P0.05),胸椎钙(水)密度随LAV%升高而减少。结论利用能谱CT图像可初步评估COPD患者胸椎钙(水)密度与肺通气功能及LAV%变化关系;肺气肿是加重COPD胸椎钙(水)密度减低的重要因素。     

三位X线摄影在肋骨骨折诊断中的应用(附228例分析)

胸部在直接或间接的暴力下,均可发生肋骨骨折。在很多病例中,首次检查采用常规胸部正位X线摄影可未发现确切骨折征象。约2~21 d患者第2次复查发现肋骨骨折,或者原认为是单发性肋骨骨折,实际为多发性肋骨骨折,由此引起的医疗纠纷时有发生,因骨折的数量、对位情况在伤害的程度及伤残等级鉴定上起着决定性作用[1],为此我院采用三位摄影法,即胸部正位、肋骨切线位及胸部卧位,对胸部外伤性肋骨骨折的诊断水平有较大的提高,现介绍如下。1材料与方法1.1材料收集我院2000~2003年期间228例临床资料完整的肋骨外伤采取三位X线摄影病例。其中男173例,…     

Interleukin-1α (IL-1α) and N-formyl-methionyl-leucyl-phenylalanine (FMLP) as potential inducers of supravital chemotaxis

The phenomenon of artificially induced local leucocyte reactions during the supravital period could be of practical importance, but has not yet been comprehensively investigated. For a more detailed evaluation, experiments with the chemotactic agents interleukin-1 (IL-1) and N-formyl-methionyl-leucyl-phenylalanine (FMLP) were performed by subcutaneous injection into various anatomical regions (back, abdomen, limbs) of NMRI-mice (National Medical Research Institute) and pigs 0–5 min after circulatory arrest. Phosphate buffered saline (PBS) without effective components was administered to equivalent areas of the animals as a control. Tissue specimens were collected at 6 h postmortem (mice) and 12–14 h postmortem (pigs), cut into serial sections, stained with H & E and examined under the microscope. A leucocyte reaction did not develop in pigs (n = 10, 30 tissue samples) following injection of FMLP, however, dermal, subcutaneous and perivascular infiltration of leucocytes (in particular mononuclear cells and a few granulocytes) was found in 3 out of 30 tissue specimens in murine experiments. In addition intravascular cell accumulations were detected in 2 out of 30 samples. The injection of IL-l to mice gave similar results, i.e. aggregations of leucocytes and intravascular cell accumulations in 4 out of 30 and 3 out of 30 tissue samples, respectively. In negative controls no leucocyte reaction was detectable. This shows that potent chemotactic factors such as IL-1 and FMLP administered in the early supravital period can induce moderate local leucocyte reactions in animal models in at least some cases. A clear morphological differentiation between vital and supravital chemotaxis does not seem to be possible. The supravitally stimulated accumulations of leucocytes are interpreted as an aggregation of resident macrophages in combination with a slight migration of blood leucocytes. Presumably, these alterations are restricted to the very early supravital period as long as sufficient energy reserves are available. It must be stated that the observed changes are reactions, not spontaneous actions, so that the general validity of the phenomenon of leucocyte infiltration as a vital parameter is not affected.     

测定土壤和沉积物中低水平~(237)Np的α能谱法

本文介绍一种准确、可靠测定土壤和沉积物中低水平~(237)Np的α能谱法.取空气干燥的土壤或沉积物样品50～100g,45℃焙烧后转入1～2L的烧杯内,加入300～500ml王水和约500Bq~(239)Np.加热微沸几小时后,趁热用玻璃纤维滤器滤出不溶物,不溶物再用王水处理并过滤,合并两次滤液并蒸干.此残渣用含几毫升H_2O_2的10mol HCl 200～300ml微热溶解,若溶液中仍有可见残渣,过滤除去.用异丁醚萃取法除去溶液中大最的Fe(Ⅲ)后加入HI,使其浓度达0.05～1mol,在70～80℃加热30分钟.溶液冷却后,三次萃取四价Np至50ml