2002 Guess Nuclear Med

1 Nuclear Medicine Guess Paper 1. How many portions can the nuclear medicine divided in to? Generally speaking, clinical nuclear medicine may be divided into two divisions: the 1st division is In Vivo Study Another division is In Vitro testing (assay) In Vivo: Suitable pharmaceuticals are applied in side the human body and the distribution of the radioactivity in the body is determined by the external detector. It can be used as diagnosis or treatment of some disease. eg. liver scan, brain scan for the detection of a tumor, whole body imaging skeletal survey for the detection of metastases. In Vitro: It is also called radio immune assay Radio-pharmaceuticals are not applied in side the patient body. It is used in order to measure the concentration of tracer substances, such as, hormones, antibodies, drugs and other clinically important substances in samples of blood or tissues. 2. What are the synonyms for radionuclide imaging? The many synonyms for radionuclide imaging include: a. Nuclear Imaging b. Isotopes Imaging c. Nuclear Medicine Imaging d. Gamma Scintigraphy, e. Nuclear Scanning f. Nuclear Medicine Scanning g. Isotope Scanning h. Radionuclide Scanning 3. DEFINATIONS: Isotopes of the element: Atoms with the same number of protons but differing numbers of neutrons are called isotopes of that element. Eg. I131& I123. Nuclide: A nuclide is a species of atom with a particular combination of atomic number (z), atomic mass number (A) and in certain cases 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. Eg. 99mTc & 99Tc Radiation: Energy emitted by atoms undergoing internal change, transferred through space or matter, is called radiation. Activity: The activity (The intensity of a radioactive source.) of a radioactive element is usually given in disintegrations per second (dps), the old standard activity is the Curie (Ci), which is equal to 37 billion (37,000,000,000)dps. 1 dps= 1s-1= 1 Bq (Becquerel) In nuclear medicine, the amounts of radioactivity administered vary from microcuies to millicuries. 1Ci =3.7×1010Bq= 37×109 Bq=37 GBq 1mCi =3.7×107 Bq= 37×106 Bq=37 MBq 1μCi =3.7×104 Bq= 37×103Bq= 37 KBq Half life: The other important aspect of radioactive decay is the 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. The real measure of radiation exposure is related to the effective half-life ((T1/2)eff) of a radioisotope in the body. The (T1/2)eff is given by the formula (T1/2)eff=(T1/2)p×(T1/2)b/[(T1/2)p+(T1/2)b] where (T1/2)p is the physical half-life, and (T1/2)b is the biological half-life. Electron volt: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).

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4. How many kinds of radiation? Which partical can be detected by SPECT ? what is the most widely used radioisotopes in nuclear medicine? Which particle can bedetected by PET ? Which particle can be used to treat disease? There are three basic kinds of radiations, which were named for the first three letters of the Greek alphabet: alpha, beta, and gamma radiation. SPECT can detect “Y” particle . 99mTc (technetium-99m) is the most widely used radioisotopes. “B” particle is detected by PET. 5. What are the radiopharmaceuticals of cerebral perfusion imaging? What did the hot and the cold spot reflect with cerebral perfusion imaging? The clinical application of cerebral perfusion imaging. 99m 99m 123 133  Tc-HMPAO…… Tc-ECD,….. I-IMP and Xe Hot spot reflect the area of the high perfusion and cold spot reflect the area of low perfusion. The clinical application of the cerebral perfusion imaging are: 1. Epilepsy : the Detection of a Seizure focus: 2. Acute CNS Ischemia / Infarction: 3. Transient Ischemic Attacks: 4.Brain death 5.Cerebral hemorrhage 6.Preoperative temporary balloon occlusion of the internal carotid artery 7 Dementia: Alzheimer’s Dementia, Parkinson’s Disease, Multi-infarct Dementia, HIV, Pick’s Disease 8.Psychiatric Disorders: 9. Schizophrenia: Attention Deficit-Hyperactivity Disorder (ADHD), Bipolar Disorders, Unipolar Disorders, Autistic Disorder 6. How many radionuclide techniques have gained widely clinical acceptance in cardiac studies? Which techniques can be performed with the patient at rest and or during exercise? Why? Three radionuclide techniques have gained wide clinical acceptance they are: 1. Measurements of cardiac function 2. Evaluation of regional myocardial perfusion. 3. Detection of acute myocardial infarction. 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. 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. 7. What are the radiopharmaceuticals of equilibrium multiple-gated blood pool imaging and myocardial perfusion imaging? Interpret the data collection (frame mode) of equilibrium multiple-gated blood pool imaging.  The radiopharmaceutical used for the exam must be retain within the blood pool, includes: 1. 99mTc-tagged RBC's, Abnormal Stress Rest or redistribution Interpretation 2. Nomal Not done No evidence of CAD 3. 99mTc-human serum Abnormal Nomal Ischaemia albumin. 4. 99mTc-synthetic Abnormal but improved Ischaemia and infarction polymers Myocardial perfusion imaging is well Abnormal Abnormal / no change Infarction established that myocardial perfusion may be normal at rest in the presence of significant coronary obstruction.

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8. Interpret the EF.PEF,PFR, the amplitude image, the phase image. End Diastolic Counts - End Systolic Counts EF is the short form of left ventricular ejection fraction.PEF is defined as peak EF = ------------------------------------------------------End Diastolic Counts - Background emptying rate and PFR is defined as peak filling rate. 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 imaging can be useful in detecting asynchronous ventricular contraction. The timing of regional ejection (contraction) in each cardiac pixel appears on the phase image.  If two pixels defining the heart reach a maximum (end-diastole) or a minimum (endsystole) at the same time, then there is no phase difference between the two.  The phase image readily identifies abnormal timing of ventricular contraction.  The atria and ventricles are 'out of phase'- they contract at different times approximately 180 degrees apart. 9. The clinical application of equilibrium multiple image-gated blood pool imaging. The clinical application of equilibrium multiple image-gated blood pool imaging are: 1. Diagnosis and Evaluation of Coronary Artery Disease 2. Acute Infarction 3. Aneurysm : dyskinesis or akinesis 4. Prognosis 10. What is the difference between 201Tl and 99mTc-MIBI in myocardial perfusion imaging? 201Tl In general, thallium clears more slowly from regions supplied by stenotic vessels than from normal myocardial regions may even accumulate thallium. This occurs because as thallium is cleared more rapidly from well perfused regions the intravascular concentration will increase resulting in a gradient from the vascular space to the low concentration (ischemic) regions (washout from normal areas and increased uptake in viable ischemic zones). Technique:Exercise---injection5-15min first imaging (stress) 3-4h second imaging (redistribution) 99mTc-MIBI MIBI,can be used to acquire high-quality myocardial images after 60 ~ 90 minutes of injection. 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) 11. What is reversible ischemic? What is irreversible infraction? Abnormalities on the stress scintigram which are no longer present at rest are indicative of reversible stress-induced ischaemia. Vice versa irreversible infraction 12. Clinical application of myocardial perfusion imaging? 1. Detection of coronary artery disease 2. Evaluation of the extent and severity of coronary stenosis 3. In order to assess prognosis 4. Assess myocardial viability 5. Assess outcome and efficacy of therapy 6. Evaluation of patients who have an uninterpretable ECG stress test 13. Clinical application of ventilation perfusion injury?

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14. Why can the bone scan detect the bone metastasis earlier that X-ray? What are the characteristics if bone metastasis? • Bone scan is more sensitive than radiographs in detecting skeletal metastases. This is probably because about 50% of the bone mineral content must be lost before a met is evident on a radiograph. • Multiple and randomly distributed hot sports in the skeleton are characteristic of bony metastases; serial hot spots in the ribs are often the result of multiple fracture. 15. Please describe the clinical application of the bone scan? a. Metastasis bone malignancy b. Solitary pubic bone metastases c. Wide spread metastases prostate cancer d. Multiple bone metastases e. Primary bone metastases f. Primary bone malignancy g. Osteosarcoma (primary bone tumor) h. Vertebral compression fracture i. Metabolic bone disease j. Pagets disease 16. What is the principle of test of thyroid function? Plasma iodine in the form of iodide is concentrated (trapped) in the thyroid cells by an energy requiring active transport mechanism where it is incorporated into T3 (triiodothyronine) and T4 (thyroxine) via organification (Therefore, iodine measures both trapping and organification by the thyroid gland). These active hormones are stored in follicles as thyroglobulin 17. How about the normal value of the test of thyroid function and how to diagnosis hyperthyroidism and hypothyroidism? Normal value of thyroid function test: FT3 3.2~9.2 Pmol/L FT4 9.1~25.5 Pmol/L TSH 0.4~4.5 mU/L By vitro function test we can diagnosis hyperthyroidism or hypothyroidism: TSH The devlopment of new sensitive immunoradiometric (IRMA) assays to measure serum thyroid hormone (TSH, thyrotropin) has been a valuable tool in the diagnosis and management of thyroid diseases. The expected normal range for TSH is 0.4-4.5mU/L. Older insensitive TSH-RIA assays could only measure concentrations as low as 0.5 mU/L. With the new sensitive TSH assays, TSH concentrations as low as 0.001 mU/L. With the new sensitive TSH assays, TSH concentrations as low as 0.001 mU/L can be detected. Measuring the serum TSH has become the screen test of choice for thyroid disease. Primary hypothyroidism produces elevated TSH levels whereas patients with primary hyperthyroidism (i.e. Graves) should have undetectable TSH values. 18. What are the common radiopharmaceuticals in thyroid imaging? How about the doses imaging time? Common radiopharmaceuticals used in thyroid imaging are:  Iodine-123, / 4 hours  Iodine-131 /24-28 hours  Technetium-99m Pertechnetate ( 99mTcO4¯ ) /1 hour Probably less than half of cold lesions are due to carcinoma, but the incidence is higher in young patients.

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19. How many kinds of nodules we can see in thyroid imaging? What are the definition of these nodules. Which disease these nodules may be respectively? Two kinds of hot and cold nodules Hot nodules: A nodule which accumulates radioactivity more than the surrounding tissue is hot nodule. It is very rare for a malignant tumor of the thyroid to show increased activity. Cold nodule: If the nodule accumulates fewer radioactivities than the remainder of the gland, it is ‘cold’ nodule and may be due to cyst, infarct or carcinoma. 20. Please describe abnormal radioactivity distribution on bone imaging and explain why does it be? • 1. Hot spots; • 2. Cold spots ; • 3. Hot spots without bone; • 4. Super-bone scan; • 5. Flare Phenomenon Bone scan is more sensitive than radiographs in detecting skeletal metastases. This is probably because about 50% of the bone mineral content must be lost before a met is evident on a radiograph. • Multiple and randomly distributed hot sports in the skeleton are characteristic of bony metastases ; serial hot spots in the ribs are often the result of multiple fracture About 90% of patients with skeletal metastases present with multiple lesions. Nearly 80% of all metastatic lesions are in the axial skeleton. In patients with a known malignancy, 60 to 70% of axial lesions are due to mets, whereas about 40 to 50% of lesions in the extremities or skull are due to mets. A solitary rib lesion has about a 10% probability of representing a met in a patient with a known malignancy • A single hot spot carries no diagnostic specificity and may result from a variety of benign or malignant conditions . • a single lesion has about a 11% probability for being a met in patients with known underlying malignancy. The percentage increased to 35% when 2 new lesions were detected, and reached 100% when 5 new lesions were identified 21. How can we diagnose renal artery stenosis with renal blood flow and dynamic renal imaging? • On renal blood flow imaging the two kidneys doesn’t appear at the same time. Two renal imaging time after abdominal aorta appear is discrepant above 1s (1 frame)and the blood perfusion of the lesion side is poor.The size of the lesion kidney is smaller than the normal one. • On the renal dynamic imaging lesion kidney is also smaller.If the renal failure occurs it can also imaging or imaging fading delay. 22. Why do the lesions of bone reveal hot spots on bone imaging?

23. Please describe abnormal renogram and their clinical significance? Rapidly Ascending Curve If double kidneys represent the same type of the Rapidly ascending curve the patient may be have a acute renal failure and it is whthin the phase of uropenia, or with the secondary affection of the lower urethremphraxis . A single side kidney has the type reveal that there is a obstruction on the upper ureter. High Level Extending Curve High level extending curve always being found on the patient with a upper ureter obstruction accompanied by hydronephrosis.This curve clarifies that the time of obstruction is short and the renal function is good right now.But urine can not drain out of the kidneys.

6 Urinary tract obstruction is a very common problem, which if untreated may lead to progressive renal damage and renal failure. Early and accurate diagnosis is therefore of paramount importance. The obstruction may be acute or chronic, high grade or low grade, persistent or intermittent, hence the assessment of renal function and its changes with time are important in selecting the therapeutic intervention Parabola Parabola type frequently being found on the patient with renal ischemia, renal dysfunction, upper ureter obstruction accompanied by slight or intergrade hydronephrosis. The pre-renal, renal and post renal factor can all influence the type of the curve. Low Level Descending Curve Low level extending curve The curve reveals that the renal function was severely damaged by any cause and often found on the patients with uraemia. Low level descending curve If the curve appears that the function of the kidney vanished. Ladder Type descenging Curve Ladder type descenging curve presents itself in the nervous patients and the patients with urinary system inflammation, pain and uropenia due to the upper ureter of these patients contracts or spreads convulsively . Small renogram is defined by the ratio : the counts of segment b left minus segment b right to the average counts of segment b >30%,and the shape of the small renogram is normal. The kidney of Small renogram side must have a renal artery stenosis , but you must excludes postural factor affected Clinical significance: Renal artery stenosis, renal failure ,urinary tract obstruction. Renal calculi and hydro nephrosis, Hydronephrosis and hydroureter , Congenital malformations ( clevis kidney) 24. If there is a patient with hemangioma, how can you do to make correct diagnosis with nuclear medicine technique? Liver hemangiomas are the most common benign tumour of the liver .The cavernous hemangioma is a benign tumor of the liver with an uncomplicated course,that is ,it does not usually cause the patient any problems . They can appear as either single or multiple lesions .They are often discovered on Ultrasound or CT,but these tests are unable to confirm whether they are a hemangioma or a malignant tumor . When the nuclear medicine 99mTc labeled RBC study is performed well it can be almost 100% accurate in confirming the diagnosis. MRI is a very good imaging modality for hemangioma but is far more expensive and not reliably available . It is essential to give an accurate diagnosis for hemangioma because if the patient is sent for a biopsy there is a great risk of haemorrhage. A 99mTc labeled RBC study using planar imaging can reliably detect lesion as small as 2-3cm, SPECT imaging can detect lesions as small as 1-2cm. SPECT therefore is the ideal imaging procedure for locating hemangiomas Cavernous hemangioma is the most common benign liver tumor with a 3 to 7% incidence from autopsy data . They are typically asymptomatic (only about 10% of patients have symptoms). Rupture with hemoperitoneum is a rare, but potentially serious complication. The lesions are most frequently subcapsular (peripheral) in the right lobe. Hemangiomas are typically solitary,but may be multiple (10-20% of cases). Treatment is not usually necessary. On pathologic analysis the internal architecture of the lesion changes with growth, and there may be hemorrhage, fibrosis, or calcification. Hemangiomas lack a capsule, but are well marginated Hemangiomas appear as radioactive deficient or defect(cold spot ) lesions on colloid scans. 99mTc-RBC imaging is the most specific test available for the diagnosis of cavernous hemangioma. (Sensitivity 90% for lesions larger than 1.5 to 2cm; Specificity approaches 100%; Accuracy 90-95%) With SPECT lesions down to about 1cm in size can be detected. [SPECT sensitivity by size: 1.5 cm (100%), 1 cm (65%), 0.5 cm (20%)] False negatives may occur due to small size of the lesion, lesion adjacent to a vascular structure ( vein, liver hilum, or heart),or

7 thrombosed/fibrosed lesion. Lesions located deep within the liver may not be detected by planar imaging, but are often readily demonstrated with SPECT. The classic findings of hemangioma on 99mTc-RBC imaging are decreased activity within the lesions on flow and early blood pool images, with increased activity on delayed scans at 1 to 2 hours post injection ( Hot spot on delayed imaging). Hepatomas will show increased perfusion due to their predominant arterial blood supply,and decreased uptake on delayed images. However, 80% or more of malignant lesions are hypovascular throughout the first phase of the exam and remain poor radioactive uptake on delayed images. Hepatomas occasionally have uptake equal to the liver on delayed images. 25. What is RIA? Please simply describe the usages of quality control samples (when we must repeat the assay) RIA is 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.  Usage of quality control samples A control may be a standard or any known concentration of test material that serves as a comparison between successive runs (inter - assay), whereas the usual standard involves varying concentration used to evaluate individual samples within a single run ( intra-assay). Controls may vary in concentration ranges so that high, medium, and low ranges are covered . Controls and standards are solutions that contain known amounts of material, but their end uses may differ. the following situation occurs,the assay must repeat: 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.