Ans Of Nuclear Medicine

1A------ Division of Nuclear Medicine Clinical nuclear medicine may be divided into two divisions: the 1st division is In Vivo Study Another division is In Vitro testing (assay) B------many synonyms for radionuclide imaging include nuclear imaging, isotope imaging, nuclear medicine imaging, gamma scintigraphy, nuclear scanning, nuclear medicine scanning, isotope scanning, Radionuclide scanning. C--------- Isotopes Atoms with the same number of protons but differing numbers of neutrons are called isotopes of that element. 131I, 123I 125I 127I Nuclide: A nuclide is a species of atom with a particular combination of atomic number (z), atomic mass number (A) and in certain cases of the nuclear energy state. Isomer: An isomer is a species of atom with the same number of protons and same number of neutrons but differing cases the nuclear energy state. 99mTc, 99Tc m denotes a metastable or prolonged intermediate state in the decay of molybdenum-99 to technetium-99 Radiation: Energy emitted by atoms undergoing internal change, transferred through space or matter, is called radiation. Radioactivity is quantitatively measured as the number of atoms that disintegrate per unit time. Physical half-life (T1/2), which is defined as the time required for one-half of the atoms in a group of radioactive atoms to decay. Energy of radioactivity decay-----The unit used to describe the energy of radioactive decay and of atomic radiation is the electron volt（eV）, usually expressed in multiples of a thousand (kiloelectron volts, keV) or millions (megaelectron volts, MeV). 2-----A-----There are three basic kinds of radiations, which were named for the first three letters of the Greek alphabet: alpha, beta, and gamma radiation. B------SPECT-----gamma rays C------The most widely used radioisotope in nuclear medicine is technetium-99m. D------PET-------positron E------To treat diseases-----beta particle 3-----A-----main difference in pharmaceuticals are : Conventional brain scintigraphy. The radiopharmaceutical can’t cross the intact blood brain barrier. SPECT Functional brain scintigraphy. The radiopharmaceutical can cross the intact blood brain barrier. Brain perfusion scintigraphy SPECT Brain metabolism scintigraphy PET Brain neuroreceptor scintigraphy PET B---------The main radiopharmaceuticals for cerebral perfusion imaging are…… 99mTc-HMPAO, 99mTc-ECD, 123I-IMP C------------hot spot reflect the area of the high perfusion and the cold spot reflect the area of low perfusion

4--A-------Clinical application of cerebral perfusion imaging….. 3.1 Epilepsy: the Detection of a Seizure focus: 3.2 Acute CNS Ischemia / Infarction: 3.3 Transient Ischemic Attacks: 3.4 Brain death 3.5 Cerebral hemorrhage 3.6 Preoperative temporary balloon occlusion of the internal carotid artery 3.7 Dementia: Alzheimer’s Dementia, Parkinson’s disease, Multi-infarct Dementia, HIV, Pick’s Disease 3.8 Psychiatric Disorders: Schizophrenia； Attention Deficit-Hyperactivity Disorder (ADHD), Bipolar Disorders, Unipolar Disorders, Autistic Disorder. B------During ictal phase and inter-ictal phase of epilepsy what are the characteristic of a seizure focus on cerebral perfusion imaging respectively? During the ictal phase of a complex partial seizure, there is typically hyper perfusion of the medial or lateral aspects of the affected temporal lobe. During inter ictal phase it is hypoperfused state which will demonstrate an area at diminished tracer activity at the seizure focus. 5------A---How many radionuclide techniques have gained widely clinical acceptance in cardiac studies? Three radionuclide techniques have gained wide clinical acceptance: Measurements of cardiac function Evaluation of regional myocardial perfusion. Detection of acute myocardial infarction. B---which techniques can be performed with the patient at rest and/ or during exercise? The first two of these techniques, the measurement of cardiac function and the evaluation of regional myocardial perfusion, can be performed with the patient at rest and / or During exercise. C-----why? It is well established that myocardial perfusion may be normal at rest in the Presence of significant coronary obstruction. At rest, blood flow to myocardial regions perfused by stenotic could be similar to that perfusing regions supplied by totally patent vessels. Since radionuclide distribution parallels blood flow, we would expect homogenous radioactivity throughout the cardiac image at rest in patients With normal, as well as in patients with stenotic coronary vessel. D----what are the pharmaceuticals of equilibrium multiple gated blood pool imaging and myocardial perfusion imaging? The radiopharmaceutical used for the exam must be retain within the blood pool, includes: 99mTc-tagged RBC's, 99mTc-human serum albumin. 99mTc-synthetic polymers Pharmaceuticals of myocardial perfusion imaging? 1.1 201Tl (Thallium)

1.2 99mTc-MIBI (2-methoxyisobutylnitrate) 1.3 99mTc-Sestamibi E----visual inspection subjectively grades wall motion as normal 2.9 EDV/s (end-diastolic volumes per second) PFR > 2.7 EDV/s Amplitude image….. The amplitude image shows the magnitude of blood ejected from each pixel within the ventricular chamber. Lower values are displayed for those regions of the heart associated with hypo- or akinesis. Phase image… Phase imaging can be useful in detecting asynchronous ventricular contraction. The timing of regional ejection (contraction) in each cardiac pixel appears on the phase image. The atria and ventricles are 'out of phase'- they contract at different times approximately 180 degrees apart. 7-----A---difference between 201TI and 99m Tc-MIBI in myocardial perfusion imaging? 201Tl Redistribution In general, thallium clears more slowly from regions supplied by stenotic vessels than from normal myocardial regions, may even accumulate thallium. Technique: Exercise---injection 5-15min first imaging (stress) 3-4h second imaging (redistribution) 99mTc-MIBI As the 99mTc-MIBI do not significantly redistribute it was initially thought that a second day injection at rest would be necessary. Technique: First day - Exercise---injection 60-90min first imaging (stress) next day - At rest -----injection 60-90min second imaging (rest similar to 201 Tl- redistribution) B------Clinical Application of myocardial perfusion imaging Detection of coronary artery disease Evaluation of the extent and severity of coronary stenosis In order to assess prognosis Assess myocardial viability Assess outcome and efficacy of therapy

Evaluation of patients who have an uninterpretable ECG stress test C------characteristic of reversible ischemic and irreversible infarction Reversible ischemia –abnormalities on the stress scintigrams which are no longer present at rest are indicative of reversible ischemia. Irreversible infarction –defect in the stress scintigrams as well as rest scintigrams is an indication of irreversible infarction. 8—A---CLINICAL APPLICATIONS of ventilation perfusion imaging…. Pulmonary Embolism Chronic Obstructive Airway Disease On V/Q scanning, a pulmonary embolism is characterized by a ventilation-perfusion mismatch….. On V/Q scanning a COPD is characterized by a ventilation perfusion match…… 9---A----Principle of TRIU Plasma iodine is the form of iodine is trapped in the thyroid cell by an energy requiring active transport mechanism where it is incorporated into t3 and t4 via organification. These active hormones are stored in follicles as thyroglobulin The normal distribution of iodine and its radiotracer isotope is in the thyroid, salivary gland etc B---plz describe the manifestation of the patient of hyperthyroidism and hypothyroidism when were measured by TRIU? Manifestation of patient of hyperthyroidism measured by TRIU Grave’s disease TSH-secreting pituitary adenoma. Manifestation of patient of hypothyroidism measured by TRIU. 1 primary or secondary (insufficiency pituitary TSH secretion) 2 surgical? Radioiodic ablation (separation) of thyroid. C---In thyroid imaging< how many kind of radionuclide can be used? TheRadiophamaceutical in in vivo 131I : 5~10 uCi 123I :200~300 uCi Radiopharmaceuticals in thyroid scintigraphy I-123 I-131 Tc-99m D---how many kind of nodules we can find? We can find three types of nodules hot, cold and intermediate…. Hot nodule :has greater or more radioactivity than the normal surrounding Thyroid tissue, Benign Autonomous (50%) Adenomatous hyperplasia Compensatory hypertrophy Physiologic thyroid hyperplasia Malignant Thyroid carcinoma (less than 4%) “Cold nodule”: has less activity than the normal surrounding thyroid tissue, Benign (80~85%) Simple cyst Adenomatous hyperplasia Focal hemorrhage Inflammatory Parathyroid adenoma Malignant (20%)

Thyroid carcinoma Parathyroid adenoma/ carcinoma Thyroid lymphoma Metastatic disease “Indeterminate nodule”: has activity equal to the adjacent thyroid gland A thyroid suppression test may be performed to determine if the nodule is autonomous or cold. Cold nodules require further evaluation to exclude malignancy. E---principle of the 131I treatment of the hyperthyroidism? I-131 Therapy for Hyperthyroidism Technique I-131 is the treatment of choice for patients over the age of 30, or those with medical complications of their thyroid disease. The dose of I-131 is approximately 80-200 uCi per gram of thyroid. Dose Determination: Dose= (Thyroid mass [gms] x 80-200 uCi/gm)/ Percent uptake 10—A----Principle of cerebral perfusion imaging…. The radiopharmaceuticals can cross the intact blood brain barrier. The distribution of the radiopharmaceuticals in the brain is proportional to regional cerebral blood flow (rCBF). B---Clinical application… 3.1 Epilepsy: the Detection of a Seizure focus: 3.2 Acute CNS Ischemia / Infarction: 3.3 Transient Ischemic Attacks: 3.4 Brain death 3.5 Cerebral hemorrhage 3.6 Preoperative temporary balloon occlusion of the internal carotid artery 3.7 Dementia: Alzheimer’s Dementia, Parkinson’s disease, Multi-infarct Dementia, HIV, Pick’s Disease C---difference between nucler medicine imaging and CT and MRI imaging Cerebral SPECT is more sensitive than CT in the early (first 24 hours) detection of acute ischemia (sensitivity 88-95% vs. 20-63% for CT, MRI has a sensitivity of about 80% for the detection of acute infarction). The defects noted on SPECT are also frequently larger than those noted on CT in about 50% of patients. 11—A----Principle of lung perfusion imaging… The lung examination is performed to determine The distribution of the air space (ventilation) and The distribution of blood flow (perfusion–sometimes abbreviated as Q) in the lungs. The ventilation and perfusion scans (sometime called V/Q scans) are frequently used To diagnose pulmonary emboli. After intravenous injection the particle, which pass through the right atrium and Right ventricle, where they are well mixed with blood, and then into the pulmonary Artery. They pass out into the blood vessels of the lung until they become impacted in the Terminal arterioles and capillaries because they are too large to pass through them. 30 to 40μm Diameter of capillary is about 8~9 μm. B-----Principle of lung ventilation imaging The body maintains a precise regulation of the distribution of perfusion based upon A continuous sampling of the level of oxygen in the alveoli. When the partial pressure of oxygen in a segment of lung is low, pulmonary blood Flow is directed away from that area.

If an imaging of the regional distribution of perfusion is recorded without any Knowledge of the regional distribution of ventilation, it is difficult to determine if The blood flow was directed away from that area because of Decreased local oxygen content or Secondary to a mechanical (embolic) obstruction. C----- Characteristic of Pulmonary Embolism A pulmonary embolus occurs when a thrombus forms the wall of the vein, and Circulates through the heart to enter the lung. These events are more likely to occur in bedridden or sedentary people that in Active, healthy individuals. D----how to diagnose PE with these two nm imagings. No single or combination of, clinical findings is either specific or sensitive enough to diagnose or exclude PE. Symptoms of pulmonary embolism include tachypnea (most common), tachycardia, hypoxia, pleuritic chest pain, hemoptysis, and atrial fibrillation. Massive PE may be associated with cor pulmonale and the ECG may show right axis deviation, P-pulmonale, RBBB, or other evidence of right heart strain. A normal arterial blood gas does not exclude the presence of a PE. Although PE occurs most commonly from deep venous thrombosis in the lower extremity, about 10% arise from clot in the upper extremity primarily associated with an indwelling catheter. 12---A---what are the liver imaging and liver blood flow imaging and liver blood pool imaging? Liver imaging is an accurate noninvasive method to delineate overall organ size, the presence of focal lesions, and/or the degree of hepatocellular dysfunction in diffuse liver disease. Liver scans help diagnose disorders such as cirrhosis, hepatitis, tumors and other Problems in the digestive tract. Principle of liver imaging Kupffer cells （the reticuloendothelial cells in the liver) constitute 15% of the Hepatic mass. They phagocytose foreign particles and they can be imaged with Colloid tracers such as 99m Tc-sulphur colloid or 99m Tc-phytate. Radionuclide Liver scans are performed after intravenous administration of 99mTc labeled to a colloid that is trapped by the reticuloendothelial cells, most of Which are located in the liver, spleen, and bone marrow. The radio colloid liver scan provides an image of the functional behavior of reticuloendothelial cells that depends on cell numbers, distribution, integrity, and blood supply. Clinical application of liver imaging. To assess the configuration (it’s size , shape, location and the relation to other organs)of the liver and see if there is a normal anatomical variation. 2. To detect the presence, number, location and size of space-occupying lesions, Such as cysts, abscesses, and tumors (primary or secondary), and to locate a site for liver biopsy. 3. To assist in the diagnosis of diffuse liver disease, such as cirrhosis, hepatitis etc. Definition and principle of Liver blood flow and blood pool imaging. The liver scan may be profitably extended in certain situations by studying the initial blood flow of the radionuclide to it or by a subsequent scan with a blood-pool marker. The combination of reticuloendothelial(colliod liver scan) and blood-flow scanning is helpful in some cases in differentiating a malignant tumor from an abscess or a cyst . The reason for this is that the malignant tumors are

often vascular at least in part but abscess or a cyst is avascular. And depend on the reason that malignant tumors contain a lot of arterial tube and hemangiomas contain a vast venous blood, we can use liver Blood Flow and Blood Pool Imaging to differentiating them. Clinical application of liver blood flow and blood pool imaging… 1.To differentiate the space-occupying lesion on the colloid liver scan ; 2.Diagnosing the hemangiomas; 3.To detect the blood supplying and it's capacity of malignant tumors in order to provide a better chemical treatment scheme and to predict the relapse of the malignant tumor. 13-- A--- principle of bone imaging….. Bone, like other connective tissues, consists of living cells and a predominant amount of nonliving intercellular substance that is calcified. It is a metabolically active tissue with large amounts of nutrients being exchanged in the blood supplying the bone. Thus the skeleton and body fluids are in equilibrium. The bone salt mineral (inorganic matter) has the crystalline form of an apatite, and the main anion constituent of bone is phosphorus (as phosphate) The accumulation of phosphate compounds is related to the exchange of the phosphorus groups onto the calcium of hydroxyapatite. Indications of bone imaging….. 1.Skeletal pain in patients with a history of cancer and negative x-rays ; 2.In patients with x-rays suspicious but not confirmatory of metastases ; 3.In excluding bony metastases in a patient with cancer but no bone pain and a negative x-ray skeletal survey; 4.In patients with a known metastasis, since the scan may reveal more widespread lesions than were first suspected ; 5.For finding suitable sites for the biopsy of a bony lesion; 6.For planning radiotherapy of bony tumors ; 7.For the evaluation of treatment of bony tumors; 8. In patients with lymphoma and apparent solitary myelomas where bony involvement may be suspected ; 9. In patients in whom osteomyelitis is suspected but the x-ray is negative; 10. Occasionally in fractures to assess if they are recent or old, to diagnose small bone fracture, e.g. scaphoid fracture and occult fracture; 11. In the detection and assessment of joint disease in various arthropathies and metabolic bone diseases. 12. In the detection of metabolic bone disease. Clinical findings of bone metastatis…. multiple and randomly distributed hot spots multiple lesions 14-----A----- principle of kidney dynamic imaging…. B…….. method of kidney dynamic imaging… There is no patient preparation . Patient lying down on the exam table , The probe of camera or SPECT is located to the back area of kidneys. A bolus radiolabelled tracer (usually 99mTc-DTPA) is intravenously injected quikly to the patient’s vein and immediately we collect the imaging data at a speed of 1 frame/s for 30s and get a series imaging of 30 frames. After or without the renal blood flow imaging procedure we take the renal images at the speed of 1 frame/30s for 1170s or 1200s and get a series of images of 59 frames or 60 frames . with the determined computer programmes we can process the imaging data to get the quality or quantity results. Clinical application Dynamic imaging:

1.Measuring relative function of each kidney; 2. Determining urinary system fistula. 3.Evaluating remaining renal function in patients with severe kidney damage; 4.Differentiating the renal space occupying lesion. (renal blood flow imaging.) ; 5.Diagnosing renal obstructive disease; 6.Diagnosing renovascular disease; 7. Monitoring renal transplantation. 15-------A----renogram---- A renogram is recording of the time-activity curve obtained from the renal areas following the intravenous injection of a suitable radiopharmaceutical. B-----principle of the 131I-OIH renogram---Two alternatively detcetor attached to a ratemeter and recorder are posited to record radioactive information from each kidney. The compound of choice( 131I-o-iodo-Hippuran ,OIH)is injected intravenously. About 90% of the Hippuran injected can be uptaken and excreted (removed from plasma ) to urine by the the renal proximal convoluted tubule cells at each passage through the kidney. The normal kidney accumulates Hippuran quite quickly.It traverses the tubular cells in a few seconds and travels along the nephrons to the renal pelvis In 2-4 min. Hippuran normally drains from the renal pelvis via the ureter almost immediately. At any given moment, activity recorded over a kidney is the sum of renal and extra-renal activity within the field of view. During these proceeding the recorder can record the variety of radioactivity and draws a time activity curve (TAC) on plotting paper outside of the body of the patient. The TAC is the renogram what we name. C------- there are total 7 types of abnormal renogram… 1- rapidly ascending curve 2- high level extending curve 3- parabola 4- low level extending curve 5- low level descending curve 6- ladder pattern descending curve 7- small renogram 16----A---- RIA---- a sensitive quantitative method for detecting trace amounts of a biomolecule, based on its capacity to displace a radioactivity labeled form of the molecule from combination with its antibody. B------ If the following situation occurs,the assay must be repeated: 1 One value of control sample between high, medium, and low ranges > or < 3SD target value; 2.Two values of control samples between high, medium, and low ranges > or < 2SD target value and at the same direction; 3. Three values of control sample > or < 1SD target and at the same direction. 17----A-----principle of competitive binding reaction of RIA---A known amount of labeled antigen is introduced into a solution containing an antibody to the antigen. At the same time, an unknown amount of the unlabeled counterpart of the antigen is also introduced into the solution . There is then a complex solution containing labeled antigen, unlabeled antigen , and antibody . These components are allowed to interact with the antibody binding both the labeled and unlabeled antigen molecules. Incubation of the components of the system (unlabeled antigen, labeled antigen, and antibody) allows an equilibrium reaction to occur. where the labeled antigen (Ag*) and the unlabeled antigen (Ag) compete for the binding sites on a specific antibody (Ab), with resultant complexes being either labeled (Ag*-Ab) or unlabeled (Ag-Ab) bound forms. By maintaining a known amount of labeled antigen, a stable amount of specific antibody , and

then separating the bound forms from the unbound forms, relative amounts of the unlabeled antigen can be determined. As more unlabeled antigen (Ag) is added to the system containing a similar labeled antigen (Ag*),more of the binding sites are occupied on the antibody (Ab) by that antigen. Consequently, fewer sites are available to the labeled antigen (Ag*) for binding. The labeled complex (Ag*-Ab) then will appear in lesser amounts .There is a reciprocal relationship between the amount of unlabeled complex added to the system and the amount of radioactivity in the labeled or "bound" complex . This relationship and the subsequent measurement and comparison of the bound and free elements of the system form the basic principle of radioimmunoassay 18---- competitive binding assays 1- Radioimmunoassay(RIA 2- Competitive protein binding assay(CPBA) 3- Radiorecptor assay(RRA) 4- Radioenzymoassay(REA) noncompetitive binding assays 1- Immunoradiometric assay(IRMA) 2- Receptor radioassay(RRA) 3- Enzymoradiometric assay(ERA)