不断深入和拓展神经核医学临床应用研究

不断深入和拓展神经核医学临床应用研究林祥通我国神经核医学从１９８３年引进ＳＰＥＣＴ以来，开始从平面显像进入断层显像的新阶段。１０年来，本刊致力于发表神经核医学基础及临床应用方面的论著，对推动我国神经核医学的发展和人才建设起了相当大的促进作用．本期刊出...     

视网膜神经受体及其分子显像研究进展

视网膜的合成、代谢等各项生理功能主要是由视网膜内的神经递质（谷氨酸、γ-氨基丁酸、多巴胺、5-羟色胺、σ受体等）协同作用完成。近年来核医学显像仪器及显像剂的蓬勃发展促进了全身各器官系统功能的分子水平研究,视网膜受体分子显像是将核医学、眼科学、分子生物学相结合的新医学技术,是当前核医学研究领域的一个开拓性的新进展。笔者将从视网膜内的各种神经递质的生理病理变化及其在核医学分子显像领域的研究进行综述。     

核医学专业基础知识(一)

核医学是一门多学科交叉的边缘学科 ,其内容涉及医学、核化学、核物理、仪器和卫生防护等领域。为使核医学工作者尤其是年轻的医师和技术人员掌握良好的核医学知识 ,更好地为临床和科研服务 ,本刊从 2 0 0 3年起开辟“继续教育”栏目 ,不定期刊登核医学专业基础知识、相关专业知识、专业知识和专业实践能力的测试题目 ,并在下一期刊出正确答案 ,以供广大读者参考。欢迎读者提出宝贵意见。     

SPECT的质量控制

本文节选自ICRP第52号出版物“核医学病人的防护”中“设备的设计、仪器使用、质量保证与控制”一节,题目略有改变根据器官断层摄影显示的基本原理,虽然SPECT的对比度和灵敏度比平面成像术闪烁明显地提高了,但是     

发展我国核医学的几点建议

发展我国核医学的几点建议叶维新根据国际上核医学发展趋势和我国核医学现状，就如何进一步发展我国核医学从三方面提一些个人看法．一、关于核医学专业人才的培养核医学专业人才的培养是发展我国核医学的关键环节，它包括在校教育和在职教育．１．在校教育：根据我国教育...     

第八届世界联盟核医学与生物学大会概况

介绍了第八届世界联盟核医学与生物学大会概况，主要内容涉及到近年来与基础和临床核医学密切相关的研究成果、新研发的放射性药物及核医学显像仪器的新进展。     

从本期几篇神经核医学论文得到的启示

从本期几篇神经核医学论文得到的启示谭天秩近十年来，我国神经核医学有较大的发展。本期刊出６篇有关论著，反映了近期研究的发展情况，其中２篇在国外完成，部分反映了国外发展的一些趋势。受这些文章的启示，对发展我国神经核医学谈谈个人的看法。１．从广度和深度上发...     

广东地区SPECT仪日常质控状况分析

为了解广东地区ＳＰＥＣＴ仪日常质控的现状与存在的问题，分析了１９９５年度２０台和１９９６年度２５台ＳＰＥＣＴ仪共４５份质控记录表。统计平面固有性能、平面系统性能和断层性能的平均实际测试率，即（实际完成的测试次数／质控网要求的测试次数）×１００％。结果显示：平面固有性能的平均实际测试率最高（１９９５、１９９６年分别为３３％和４６％），其次为平面系统性能（５７％和２２％），断层性能最低（７３％和１６％）。原因是平面固有性能测试方法较为简单，而断层性能测试涉及采集、重建等诸多因素，较为困难。１９９６年的三项平均实际测试率比１９９５年显著提高。进一步统计每一测试项目的实际测试率，结果表明用户往往选择测试较为简单易行的项目，难以对仪器质量作出完整评价。故应建立监督机制。一些质控项目实际测试率低，有必要改进，建立完备可行的日常质控规程和方法。涉及较复杂计算的项目实际测试率较低，表明应加强技术培训，提高技术人员水平。需用专用测试模型的项目实际测试率都较低，有必要在医院配备基本的质控模型，一个地区要有一套较完整的质控模型。     

国外基础核医学的最新进展

基础核医学既是临床核医学的依据,又是进一步发展临床核医学的动力。本文从稳定核素的医学应用、放射性显像剂的创新及内照射治疗的探索和核医学仪器的改进等三个方面扼要介绍国外基础核医学的新进展。     

脑SPECT图像应用解剖

脑ＳＰＥＣＴ图像应用解剖沈宗文，林祥通，刘永昌，滑炎卿应用颅脑断层标本，对照脑ＳＰＥＣＴ图像，能识别更多结构，可为核医学医生阅片提供帮助。现介绍如下。图１系通过脑底三个灰质块横位断层．脑外周约前、中１／３和中、后１／３交界处为蝶嵴和颞骨岩部切迹，分高...     

Virtual pyeloscopy using volumetric depth peeling

RATIONALE AND OBJECTIVES: The aim of the study is to test a new volume-rendering method, volumetric depth peeling (VDP), for use in virtual pyeloscopy. MATERIALS AND METHODS: VDP was applied to axial contrast-enhanced source computed tomographic (CT) images and coronal reformatted maximum intensity projections of three contrast-filled gloves containing objects of varying density. Similar renderings were performed on CT urograms performed to evaluate hematuria (n = 20). Renderings were assessed for anatomic appearance of ureters and specific calyces in comparison with source images. RESULTS: Objects of soft-tissue and calcific density ranging in size from 4 to 20 mm were identified by using VDP within the glove phantoms. Normal and deformed renal calyces were well visualized by using VDP; however, two stones were not identified. The minimal ureteral width that could be visualized was 3 mm. CONCLUSION: VDP may be a useful technique for virtual pyeloscopy providing that a robust and user-friendly computer interface can be developed.     

Differentiation of white,mixed, and red thrombi: value of CT in estimation of the prognosis of thrombolysis phantom study

PURPOSE: To test with serial computed tomographic (CT) scans whether white, mixed, and red thrombi could be differentiated according to their CT attenuation. MATERIALS AND METHODS: Platelet-enriched plasma and whole blood were mixed to produce samples with hematocrit levels of 0, 0.005, 0.03, 0.15, and 0.35. A thrombin solution was added, and after 2 hours the retracted clots were transferred into polyethylene tubes with a length of 4 cm and an inner diameter of 3 mm. Ten probes of each sample were placed into a plastic box filled with a solution of gelatin, gadopentetate dimeglumine, and distilled water. Ten tubes filled with gelatin served as control. With this phantom, the CT numbers of white, mixed, and red thrombi were measured over 144 hours. CT was performed with a multisection scanner and a collimation of 0.5 mm. Statistical analyses were performed for differences between groups and over time. RESULTS: The CT numbers of white, mixed, and red thrombi differed significantly (P <.05) for most time measurements, except for white and mixed thrombi, which had a low hematocrit level at 24 and 144 hours (P >.05). CONCLUSION: With CT it appears feasible to differentiate thrombi according to their hematocrit level and thus estimate the effectiveness of thrombolysis.     

Transtomography: a new tomographic scanning technique

OBJECTIVES: To introduce and test a new tomographic technique, namely transtomography, making it possible to expose tomographic images employing the narrow beam of an advanced panoramic machine. METHODS: The working principle of the new technique is described. It combines a translational movement with a pendular movement of the beam that creates motion unsharpness analogous to that of conventional tomography. In order to verify whether the new technique works and results in tomographic images, test radiographs were exposed on phantoms. RESULTS: The principle of transtomography works and give images with properties essentially equivalent to those of conventional tomography. With the transtomographic technique using a narrow beam, tomographic images may be exposed with an advanced panoramic machine. CONCLUSION: Transtomography may be employed to expose tomographic images basically on the same indications as for conventional tomography.     

A tomographic test object.

Testing of the tomographic and photographic system is a prerequisite for successful reproduction of minor details particularly in tomography of the temporal bone. A test phantom has been developed, consisting of a single layer of small metal balls which can be adjusted to varying inclinations to the tomographic plane. It involves a simple procedure for examining the homogeneity and stability of the tomographic layer at wide movement angles and may also be used for calculating the layer thickness.     

Comparison of In-111 granulocytes and Tc-99m albumin colloid for bone marrow scintigraphy by the use of quantitative SPECT imaging

A comparison of In-111 oxinate labeled autologous granulocytes and Tc-99m albumin colloid for bone marrow scintigraphy is reported. The aim of this report was to determine if the intense uptake in the liver and spleen with nano-sized colloids, which hampers the evaluation of the skeletal parts surrounding the liver, is reduced by the use of radiolabeled granulocytes. This study is based on a retrospective analysis of 19 abdominal tomographic examinations with In-111 granulocytes performed to detect septic foci. After correction for attenuation and scattering of photons was performed, the uptake in the bone marrow of the lumbar spine was seen to be related to the liver, spleen, and tissue background activity. The results in this study were compared with corresponding data from 20 normal liver/spleen tomographic examinations performed with Tc-99m nanocolloid, which is routinely used for bone marrow scintigraphy. The bone marrow/liver activity ratio for granulocytes varied, but it exceeded the corresponding mean ratio for colloid in all examinations. The mean values for granulocyte uptake 3 and 20 hours after injection was, respectively, about 6 and almost 10 times higher than were those for colloid. The activity ratios between bone marrow and spleen as well as between bone marrow and tissue background was not improved and or may even have been reduced by the use of granulocytes. It is suggested that granulocytes labeled in vitro by Tc-99m hexamethylpropylene amineoxime (HMPAO) or in vivo by monoclonal antigranulocyte antibodies may provide techniques for improved bone marrow imaging.     

Unilateral proptosis with thyrotoxicosis resulting from solitary retroorbital soft tissue metastasis from follicular carcinoma thyroid

Unilateral proptosis can be of neoplastic origin, even if the results of thyroid function tests suggest hyperthyroid disease, and it needs proper investigation with a computed tomographic scan of the orbit. The authors present a case of left-sided proptosis resulting from a metastasis in the retroorbital soft tissue from follicular carcinoma of the thyroid. A nodular goiter involving the left lobe and isthmus was found. The initial thyroid function test values suggested hyperthyroid disease and the patient had clinical signs of toxicity. A computed tomographic scan of the orbit revealed a left-sided retroorbital soft tissue mass, part of which was resected and found be to a metastasis from follicular carcinoma of thyroid. Total thyroidectomy was performed and the patient was treated with I-131 after operation. The proptosis resolved with I-131 treatment.     

18F-fluorodeoxyglucose positron emission tomography features of idiopathic retroperitoneal fibrosis

OBJECTIVE: To evaluate the 18F-fluorodeoxyglucose (FDG) uptake features of idiopathic retroperitoneal fibrosis (IRF). METHODS: 18F-Fluorodeoxyglucose positron emission tomographic (PET) or PET/computed tomographic findings were retrospectively reviewed in 6 patients with IRF. FDG PET or PET/computed tomography was performed 1 and 2 hours after FDG injection. The FDG level was scored using a 4-point scale, and the intensity of FDG uptake was quantified using the maximum standardized uptake value (SUVmax). RESULTS: In the 1-hours images, intense FDG uptake by IRF was observed in 5 patients before steroid treatment, but no abnormal uptake was noted in 1 patient receiving steroid treatment. The SUVmax in IRF increased from a mean +/- SD of 6.0 +/- 1.2 (range, 4.9-7.6) to 7.6 +/- 1.1 (range, 5.9-8.2) for all 4 patients who underwent 1 and 2 hours dual-time point imaging. Abnormal uptake was also noted in the mediastinum and the pancreas in 1 and 2 patients, and the diagnoses of mediastinal fibrosis and autoimmune pancreatitis were made, respectively. The SUVmax was stable or increased in the 3 lesions of mediastinal fibrosis and autoimmune pancreatitis. CONCLUSION: FDG PET may be a reliable means of evaluating disease activity and the extent of IRF, but dual-time point imaging may not be useful to differentiate malignancy from IRF.     

Comparing the image quality of myocardial perfusion agents in the clinical laboratory: small test groups and large reference populations

Myocardial perfusion studies have been performed for 6 years using technetium-99m (99Tcm)-sestamibi (MIBI). In this study we evaluated a newer agent, 99Tcm-tetrofosmin (TF), on a trial basis for 2 weeks, and compared the results from each week to those in an adjacent week of MIBI use. The routine protocol included weight-based dosing, frequent dipyridamole use, and separate-day rest and stress wherever possible. During the first week, TF was used with 'usual' image timing, i.e. stress tomography performed 30-60 min after stress, and ancillary immediate images performed 4 min after injection. For the second week, 'early' tomography was performed 15-30 min after stress. TF scans (n = 53) were compared with MIBI scans for the adjacent weeks (n = 54) and with a historical reference series (n = 1800). Blinded analysis was made of tomographic image quality, peak myocardial counts and background activity (lung and abdomen) on immediate and delayed acquisitions and on tomographic reconstructions. The TF and MIBI test groups were similar with respect to gender, weight, stress protocol, tracer doses, imaging times and scintigraphic findings. Using analysis of variance, the tomographic quality scores were similar for the two observers, with stress>rest (P<0.0001), 'usual'>'early' (P<0.001) and MIBI>TF (P<0.05). Myocardial counts were approximately 20% higher with the MIBI test group than with TF at all times after stress (P=0.001), and were similar to the reference population. MIBI with usual timing gave more favourable stress abdominal background ratios than the other three agent/timing combinations. Satisfactory images could be obtained with TF, but no apparent advantage over MIBI could be attained with earlier post-stress imaging. Subtle advantages for MIBI over TF were suggested by comparison of the small test groups. In our local imaging context, these conclusions were reinforced by a large control series.     

Angiographic ablation of parathyroid adenomas: lessons from a 10-year experience

Angiographic ablation of parathyroid adenomas with ionic contrast material was performed in 24 patients with persistent hyperparathyroidism who had undergone at least one prior unsuccessful surgical resection; 23 had mediastinal adenomas. The success rate was 83% at 1 month after ablation and 71% at both 5 and 9 years. Ablation was successful in 85% of the patients in whom the catheter could be wedged into the artery feeding the adenoma. Long-term success was achieved in 89% of the patients in whom contrast enhancement persisted in the adenoma on computed tomographic scans obtained 24 hours later. Acute complications were seen only in patients with glands supplied by the inferior or superior thyroid arteries. Long-term complications were limited to permanent hypocalcemia, present in 8% of patients. Even if unsuccessful for ablation, the procedure may provide localization and does not preclude surgical resection. It is recommended for most patients with persistent hyperparathyroidism and mediastinal adenomas, especially adenomas supplied by the internal thoracic artery.     

Same day injections of Tc-99m methoxy isobutyl isonitrile (hexamibi) for myocardial tomographic imaging: comparison between rest-stress and stress-rest injection sequences

It has been shown that both rest and stress 99mTc-hexamibi myocardial perfusion imaging can be performed on the same day using two different doses injected within few hours (the first one at rest followed by a second at stress). In order to evaluate and compare 2 sequences (rest-stress and stress-rest) of 99mTc-hexamibi injections performed the same day, 18 patients with either abnormal 201Tl myocardial scan or abnormal coronary angiography were studied with 2 99mTc-hexamibi injections protocols. The rest-stress study was performed as follows: 7 mCi 99mTc-hexamibi was injected at rest. Single photon emission computed tomography (SPECT) was performed 60 min later. Immediately after the rest study, patients were injected at peak stress with 25 mCi 99mTc-hexamibi. Tomographic imaging was repeated 1 h later. Patients were submitted to the stress-rest protocol within 3 days. Tomographic imaging was done 1 h after a 7 mCi injection at stress. This study was followed by an injection of 25 mCi 99mTc-hexamibi at rest, a tomographic study was performed 60 min later. Myocardial sections were reconstructed in horizontal long, vertical long, and short axes. Data analysis also included polar map representation. A total of 324 segments were interpreted blind by 3 observers, there was an agreement in 283/324 (87.3%) segments between the 2 protocols. However, 24 segments (7.4%) judged ischemic on rest-stress were called scars on stress-rest.(ABSTRACT TRUNCATED AT 250 WORDS)