Radiation doses of yttrium-90 citrate and yttrium-90 EDTMP as determined via analogous yttrium-86 complexes and positron emission tomography

Yttrium-90 is used for palliative therapy for the treatment of skeletal metastases, but because it is a pure - emitter, data on the pharmacokinetics and radiation doses to metastases and unaffected organs are lacking. To obtain such data, the present study employed yttrium-86 as a substitute for⁹⁰Y, with detection by positron emission tomography (PET). The study compared the properties of two different⁸⁶Y complexes —⁸⁶y-citrate and⁸⁶Y -ethylene diamine tetramethylene phosphonate (EDTMP) — in ten patients with prostatic cancer who had developed multiple bone metastases (the ten patients being divided into two groups of five). Early dynamics were measured up to 1 h post injection (p.i.) over the liver region, followed by subsequent whole-body PET scans up to 3 days p.i. Absolute uptake data were determined for normal bone, bone metastases, liver and kidney. Radiation doses were calculated according to the MIRD recommendations. Based on the pharmacokinetic measurements of the distribution of the⁸⁶Y complexes, it was possible to calculate radiation doses for the bone metastases and the red bone marrow delivered by complexes containing⁹⁰Y. In 1 cm³ of bone metastasis, doses of 26±11 mGy/MBq and 18±2 mGy/MBq were determined per MBq of injected⁹⁰Y- citrate and⁹⁰Y- EDTMP, respectively. The doses to the bone marrow were 2.5±0.4 mGy/MBq for⁹⁰Y- citrate and 1.8±0.6 mGy/MBq for⁹⁰Y-EDTMP.⁸⁶Y and PET provide quantitative information applicable to the clinical use of⁹⁰Y. This method may also be useful for the design of other⁹⁰Y radiopharmaceuticals and for planning radiotherapy dosages.     

Multidetector single-photon emission tomography: are two (or three or four) heads really better than one?

Today, almost every camera sold, with the exception of mobile systems, is single-photon emission tomography-capable. The atest technical development is the so-called multidetector systems. This article reviews the development and current and potential clinical role of these multidetector systems, with particular emphasis on multicamera systems. The utility of multidetector systems is considered in the context of an image's signal-to-noise ratio, including its effect on diagnostic or quantitative accuracy. The potential for multidetector systems to increase the signal-to-noise ratio is discussed, as are other potential benefits. Finally, advice on an approach to equipment selection is provided.     

Reproducibility of quantitative hexakis-2-methoxyisobutylisonitrile single photon emission tomography in stable coronary artery disease

The quantification of myocardial perfusion abnormalities is necessary to allow comparison of repeated studies, especially in the evaluation of the success of medical, interventional or combined treatment in stable coronary artery disease or in evolving myocardial infarction. The purpose of this study was to assess inter-observer reproducibility of tomographic study processing using a semi-automatic quantitative programme. Technetium 99m hexakis-2-methoxyisobutylisonitrile (^99mTc-Sestamibi) was chosen for tomographic imaging of repeated rest-stress studies in patients with stable coronary artery disease. The quantification was performed using a modification of the Cedars polar coding and comparison with the normal data base. The perfusion defects were quantified separately for each standard perfusion area [left anterior descending (LAD), right coronary (RCA) and left circumflex (LCX) arteries] and total area of hypoperfused myocardium. The inter-observer variability for 40 tomographic studies was accomplished. The defects were the largest in the LAD perfusion area (average 19.7% of the normalized LAD supply area) with an inter-observer correlation of 0.84 for this region. The greatest variability was found for the LCX region (r=0.55) and is attributed to a small average perfusion defect (7.1%), only 18 studies having abnormal perfusion in this area. In total, an average 14.3% of the left ventricular myocardium was significantly hypoperfused, and the inter-observer correlation was 0.87. These results show good inter-observer reproducibility using semi-automatic quantitation of perfusion defects. Careful interpretation of smaller defects in the evaluation of treatment results is advised when repeated ^99mTc-Sestamibi single photon emission tomography studies are processed by more than one observer.The work was performed at Nuclear Medicine Department in Ulm. Offprint requests to: M. Milinski     

Spontaneous improvement in reduced vasodilatory capacity in major cerebral arterial occlusive disease

Reduced vasodilatory capacity resulting from occlusive lesions of the major cerebral arteries may return to normal without surgical revascularisation. We aimed to determine prospectively the frequency and predictors of recovery of impaired haemodynamics as demonstrated by acetazolamide (ACZ) reactivity on single-photon emission computed tomography (SPECT). Vasoreactivity was measured by ¹²³I-IMP SPECT with an ACZ challenge, in 37 medically treated patients with unilateral occlusive disease of the internal carotid or middle cerebral artery at an interval of 1–2 years. Each ACZ challenge test was analysed semiquantitatively by calculating the degree of increase in cerebral blood flow (CBF) asymmetry after ACZ administration (ΔAI). Vasodilatory capacity was abnormal initially in 20 patients (65 %); eight of whom (40 %) exhibited spontaneous normalisation on follow-up. Although the baseline characteristics did not differ significantly between patients with or without increase in reactivity, logistic regression analysis revealed that the initial ΔAI (P < 0.05) and the type of vascular lesion (stenosis or occlusion) (P < 0.05) correlated significantly with a return towards normal of reduced ACZ reactivity. Spontaneous improvement of impaired vasodilatory capacity may not be a rare phenomenon. We found that mild reduction in the initial ACZ reactivity and a stenosis, but not complete occlusion, were independent factors contributing to normalisation of impaired cerebral haemodynamics. Received: 12 October 1998/Accepted: 27 April 1999     

中华大蟾蜍皮无机元素初步分析

目的：对中华大蟾蜍皮中的无机元素进行分析研究并对其中6种元素进行含量测量。方法：采用原子发射光谱法进行定性，并用等离子体发射光谱法对其中6种金属元素进行定量。结果：钙是中华大蟾蜍皮中含量最高的无机元素。     

215例正常新生儿瞬态诱发耳声发射测试分析及随访研究

目的：进一步了解正常新生儿瞬态诱发耳声发射（TEOAE）的特征，为新生儿听力筛查提供帮助。方法：采用ILO96型耳声发射仪，对出生后0（出生当天）-8d的215例（425耳）正常新生儿进行TEOAE测试，并跟踪随访结果：TEOAE总检出率为89%，检出率与检测时的天龄有一定的关系。新生儿出生后0-3d检出率平均为72%，4-8d为97%，分娩方式，左右耳，孕龄36至41周间的差异对检出率无明显影响；女性的检出率显著高于男性，快速扫描较TEOAE测试敏感，经随访确诊有1耳听力损害。结论：新生儿听力筛查应在出生后≥4d出院前进行；分娩方式对耳蜗功能无明显影响；人耳蜗毛细胞的成熟是在怀孕36周以前；快速扫描不能代替TEOAE测试；对于1耳或双耳未检出TEOAE的受测者必须跟踪随访和复检，并结合ABR测试尽早确诊。     

畸变产物耳声发射用于新生儿听力筛查的影响因素分析

目的 探讨畸变产物耳声发射(DPOAE)用于新生儿听力筛查的影响因素。方法 采用GSI-70全自动便携式耳声发射仪进行新生儿听力筛查，在筛查同时，自制问卷表，对新生儿的出生史，母亲妊娠史，家族史，父母社会阶层等35个因素进行调查，调查结果运用SPSS统计软件进行统计分析。结果 住院期间82．8％的(3242／3944)新生儿通过筛查，通过率右耳高于左耳，女婴高于男婴，单胎高于多胎，足月儿高于早产儿，正常及高出生体重儿高于低出生体重儿，阴道助产高于自然产、剖宫产，P值均小于0．05。多因素logistic回归分析，出生体重、性别、胎数与初筛结果相关。42天复筛，96．4％(3167／3284)通过筛查，影响初筛结果的因素对复筛无影响。结论 新生儿的性别、分娩方式、胎数、孕周、出生体重对应用DPOAE进行的新生儿听力筛查的初筛结果有显著影响。     

PET在肺癌诊断和分期中的应用

本文介绍正电子发射断层显像(PET)在肺癌诊断和分期中的应用概况，肯定了其临床应用价值。并简要叙述我国PET目前现状及今后展望。PET系大型医疗设备，我国未纳入医疗保险，其发展要根据社会经济发展和病人承受能力，合理布局，有限量地增加。作者指出，加强核医学科人员培训与临床各科医师(包括放射科，肿瘤科，胸外科，放射治疗等)的合作是提高PET临床应用和研究水平的关键因素。     

Subependymoma of the septum pellucidum: Characterization by PET

We report the evaluation of a subependymoma of the septum pellucidum by positron emission tomography (PET) with analysis of ₁₈F-fluorodeoxyglucose (FDG)kinetics. The tumor showed exceedingly low rates of glucose metabolism (rCMRG1) and kinetic constants (K1, K2, and K3). This hypometabolism indicates low cellular density and slow growth.     

听力正常人畸变产物耳声发射的基本特性

利用动态分析仪ＩＬＰＯ－９２，对４８例听力正常人在４组不同原始刺激强度下进行畸变产物耳声发射检查，结果发现平均ＤＰＯＡＥｓ图呈双叶型轮廓：在１．５ｋＨｚ和５ｋＨｚ附近。