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1、Nuclear medicine is a subject of diagnosing, treating and researching the disease using the emission of the radionuclide, including basic nuclear medicine, experimental nuclear medicine and clinical nuclear medicine. 运用放射性核素发射的核射线对疾病进行诊断、治疗和研究的学科。根据与否将放射性核素引入受检者、接受治疗者或研究志愿者体内，分为体外in vitro措施和体内in viv
2、o措施；体内措施根据检查成果与否产生医学影像又分显像检查法imaging exploration(18FDG脑代谢显像)和非显像检查法functional exploration(甲状腺摄131I率实验)。SPECT显像第1年全身辐射吸取剂量大概为 0.4-1.2 mSvSingle-photon emission computed tomography(SPECT, ECT) Positron emission tomography(PET)CT扫描第1年全身辐射吸取剂量大概为 3.5-3.7 mSv显像检查法：以脏器内、外或脏器与病变间的放射性浓度差别为基本的脏器或病变显像措施显像剂ima
3、ging agents：用于脏器或病变显像的放射性核素或放射性标记物 原理：细胞选择性摄取selective uptake of cell特殊需要物质 131I代谢产物和异物 131IOIH特殊价态物质 201Tl化学吸附chemical absorption 99Tcm-MDP微血管栓塞micro-vascular embolism 99Tcm-MAA特异性结合specific combination McAb GSA通道、灌注和生物辨别布path, perfusion, biological distribution 99TcmO- 99Tcm-PYP-RBC 显像的方式和种类 静态显像s
4、tatic imaging、动态显像dynamic imaging、局部显像regional imaging、全身显像whole-body imaging平面显像planar imaging、断层显像tomog初期显像early imaging显像剂引入体内后2h内所进行的显像 延迟显像delayed imaging 2h后来 阳性显像positive imaging显像剂在病变组织内的摄取明显高于周边正常组织 阴性显像negative imaging引入体内的显像剂在病变组织中的浓聚明显低于正常组织静息显像rest imaging、负荷显像loaded imaging、融合显像fusion
5、imagingNuclide is characterized by its atomic number Z, and mass number A, and a certain energy state凡具有特定的质子数、中子数及核能态的一类原子Isotope同位素 may be defined as one of two or more forms of the same element having the same atomic number (Z), differing mass numbers (A), and the same chemical properties. These
6、different forms of an element may be stable or unstable. For example, 1H, 2H, 3H are three isotopes of hydrogen凡具有相似的原子序数，但质量数不同的核素Isomer同质异能素 is one of two or more nuclides that have the same mass number and atomic number as the others but different energy state凡具有相似的质量数和原子序数，但核能态不同的一类核素Some nuclid
7、es are unstable and gain stability by emitting particles or photons or both. These unstable nuclides are called radionuclides放射性核素（不稳定，能自发的发生核内构造或能级的变化，同步能自发的放出某种射线而转变为另一种核素）, and the process of emitting particles or photons or both is called radioactive disintegration, or decay. （这种有放射性核素自发的放出一种或一种
8、以上的射线并转变为另一种核素的过程称为核衰变）radioactivity放射性活度is the number of disintegrations per unit of time, and decreases with time一定量的放射性核素在一种极短的时间间隔内的核衰变率A=dN/dT=N放射性活度单位 贝可Becquerel 1Bq1次核衰变/秒1mCi=3.7107Bq=37MBq半衰期half life物理半衰期Tp the time required for one-half of the atoms in a group of radioactive atoms to dec
9、ay.生物半衰期Tb the time required for a radionuclide in biological body to one half of the original activity by excretion . 有效半衰期Te=(Tp Tb)/(Tp+Tb) the time required for a radionuclide to one half of the original activity due to the common effect of physical decay and biological excretion 放射性药物radiopharm
10、aceuticals是指药物的自身具有放射性核素，用于人体疾病的诊断与治疗的特殊药物。临床常用放射性核素 : 99mTc、131I、201Tl、18F放射性化合物 : 99mTc-ECD、99mTc-DTPA、99mTc-MIBI、99mTc-EHIDA局部脑血流灌注断层显像Regional cerebral blood flow (rCBF) tomography1原理Imaging Principle The tracers显像剂 used for rCBF imaging must be able to cross the normal blood-brain barrier (BBB)
11、. Only the radiopharmaceuticals放射性药物 with basic properties: lipophilia脂溶性, electrically neutral电中性，small molecule小分子 can cross the normal BBB following intravenous injection and distribute within the brain in proportion to rCBF. They can remain fixed in the brain long enough to be imaged by loss the
12、 lipophilicity. Thus, we can obtain the imaging of rCBF by collecting radioactivities that are emitted by radiopharmaceuticals with single-photon emission computed tomography (SPECT). 脑血流灌注显像剂为脂溶性、电中性和小分子的物质，静脉注射后可通过正常血脑屏障。初次通过脑循环时，进入正常脑组织，局部入脑量与局部脑血流量成正比。并且一旦进入脑后即失去脂溶性，转变成带有电荷的亲水性化合物，不能再反向通过血脑屏障，因而
13、较长时间滞留在脑内。这样，运用这些显像剂具有发射射线的特性，在体外应用SPECT显像装置，进行数据采集、解决及图像重建，可获得rCBF三维图像，并可计算半定量和定量参数。2显像剂RadiopharmaceuticalThe tracers that are commonly used in rCBF imaging clinically are 123I-IMP异丙基安非它明, 99mTc-HMPAO六甲基丙烯胺肟and 99mTc-ECD双半胱乙酯. The third is the most common used in clinic. 3显像前准备123I-IMP检查前口服复方碘iodi
14、ne liquid 以封闭甲状腺，99mTc-HMPAO和99mTc-ECD检查前口服过氯酸钾potassium perchlorate 以封闭甲状腺、脉络丛和鼻粘膜4适应症Indication 1.Diagnosis of the ischemia cerebrovascular diseases. 缺血性脑血管病的诊断2.Locaton diagnosis of epilepsia. 癫痫病灶的定位3.Diagnosis of migraine. 偏头痛的诊断4.Classification of dementia. 痴呆的分型5.Judgment of the recurrence of
15、 head tumor脑肿瘤复发的鉴定6.Evaluation of neuropsychiatric disorders. 精神活动异常的研究7.Diagnosis of the parapyramid system diseases. 锥体外系疾病的诊断8. Researchment of cerebral physiological function脑生理功能的研究9. View of the efficiency of medicines. 药物疗效的观测5图像分析：正常图像-皮质明显高于白质、左右基本对称6临床应用Clinical applications 1短暂性脑缺血发作 Transient ischemic attacks，TIA：脑局部放射性分布减低区，显像距末次发作时间越短相对阳性率越高；持续低灌注：发生脑卒中2.脑梗死Cerebral infarction，CI：局部脑放射性分布减低decreased distribution或缺损defect，病变范畴不小于X-CT或MRI，较初期发现病变 过度灌注luxury perfusion：梗塞血管
