Eleanor Mantel

13 Infection Scintigraphy

1. Which of the following is true of 67Ga citrate- and 111In-labeled leukocytes? (a) Both require the use of a medium-energy collimator. (b) Both can be used to effectively image neoplasms and infections. (c) Both have three gamma peaks available for imaging. (d) All of the above. (e) (a) and (b) only. 2. In general, the best radiopharmaceutical to use for a suspected abdominal abscess is: (a) 67Ga citrate (b) 111In-labeled leukocytes (c) 111In satumomab pendetide (d) 111In octreotide 3. For imaging of inflammation or infection, leukocytes may be labeled with: (a) 111In oxine (b) 99mTc exametazime (c) 67Ga citrate (d) All of the above (e) (a) and (b) only

11 Genitourinary System Scintigraphy

1. What is the imaging protocol that was most probably used to obtain the images in Fig. 1? (a) Consecutive 1 s images for 15 s (b) Consecutive 3 s images for 45 s (c) 15 consecutive 10 s images (d) 15 consecutive 15 s images 2. Which of the following describes the activity on delayed static images in a patient with testicular torsion? (a) Decreased (b) Normal (c) Increased (d) Variable 3. Clearance of 99mTc MAG3 is by: (a) Active transport (b) Tubular secretion (c) Glomerular filtration (d) None of the above 4. Which renal imaging agent allows imaging at 6 h after injection? (a) 99mTc MAG3 (b) 99mTc DTPA (c) 99mTc GH (d) 99mTc DMSA

12 Oncologic Scintigraphy

1. How should 99mTc sestamibi be administered when used for breast tumor imaging? (a) Intramammary injection (b) Via indwelling catheter (c) Via intravenous injection in the arm contralateral to involved breast (d) None of the above (e) (b) and (c) 2. What is the optimal scanning time for neoplasm when using 67Ga citrate? (a) 4 h (b) 6 h (c) 24 h (d) 48 h 3. Lymphoscintigraphy is used to: (a) Map lymphatic channels (b) Determine drainage pathways from malignant neoplasms (c) Identify the sentinel node (d) All of the above (e) (a) and (b) only 4. 111In pentetreotide is a: (a) Potassium analog (b) Monoclonal antibody (c) Somatostatin analog (d) Radiocolloid 5. A HAMA response occurs because: (a) A kit contains pyrogens. (b) Monoclonal antibodies are produced from mouse cells which the human body recognizes as a foreign protein. (c) A patient is allergic to 111In. (d) Monoclonal antibodies are produced from human cells that trigger an immune response in the patient. 6. A dose of 111In satumomab pendetide should be _____ before injection. (a) Shielded (b) Filtered (c) Assayed (d) All of the above (e) (a) and (c) only 7. 111In satumomab pendetide is used to image: (a) Extrahepatic metastases from colorectal and ovarian cancer (b) Breast tumors (c) Neuroendocrine tumors (d) Lymphatic channels 8. Advantages of 201Tl chloride over 67Ga citrate include: (a) Much shorter half-life. (b) Less uptake in inflammatory processes. (c) Imaging may take place sooner. (d) All of the above. (e) (b) and (c) only. 9. It is possible to use 99mTc sestamibi for breast tumor imaging because there is no uptake of sestamibi in the normal breast. (a) True (b) False 10. A monoclonal antibody is developed which displays cross-reaction. This means: (a) The antibody triggers an immune response in the patient. (b) The antibody will bind antigens other than the one it was formed with. (c) The antibody can be labeled with either 99mTc or 111In. (d) None of the above. 11. Examples of neuroendocrine tumor include: (a) Pituitary adenoma (b) Small-cell lung cancer (c) Neuroblastomas (d) All of the above (e) (a) and (c) only 12. Visualization of kidneys at 48 h is _____on a scan using 111In pentetreotide and _____on a 67Ga citrate scan. (a) Normal, abnormal (b) Abnormal, normal (c) Normal, normal (d) Abnormal, abnormal 13. 18FDG can be used to image tumors because the glycolytic rate is higher in tumor than in normal tissues. (a) True (b) False 14. Which of the following are true regarding 18FDG tumor imaging? (a) PET scanning is required. (b) The patient should fast before the exam. (c) Only brain tumors can be detected. (d) All of the above. (e) All except c. 15. On a Monday morning, a technologist learns that a patient needs to be scheduled for imaging with 67Ga citrate and also a lower GI. If the ordering physician wishes that both exams be done within the week, how should these studies be scheduled? (a) Lower GI on Monday morning and 67Ga citrate on Monday afternoon. (b) Lower GI on Monday morning and 67Ga citrate on Wednesday. (c) 67Ga injection on Monday morning followed by imaging each day and lower GI at noon on Friday. (d) Inject patient with 67Ga citrate on Monday morning, send for lower GI, and then perform first imaging of gallium on Monday afternoon. 16. Pheochromocytomas are imaged using: (a) 131I MIBG (b) 131I NP-59 17. The use of PET imaging in oncology takes advantage of the _____differences between normal and neoplastic tissue. (a) Structural (b) Metabolic (c) Density (d) Hormonal 18. Hodgkin’s disease is a type of: (a) Lung cancer (b) Lymphoma (c) AIDS (d) Lupus 19. Normal areas of uptake for 67Ga citrate include all of the following except: (a) Intestinal mucosa (b) Parathyroid glands (c) Liver (d) Epiphyses in pediatric patients 20. If a low-energy collimator is used for imaging 67Ga, what will the effect be? (a) There is increased septal penetration. (b) Poor spatial resolution. (c) Decreased sensitivity. (d) (a) and (c). (e) (a) and (b). 21. F-18 fluciclovine is currently an FDA-approved imaging agent for what type of cancer? (a) Thyroid cancer (b) Lung cancer (c) Liver cancer (d) Prostate cancer 22. What is the half-life of Ga-68 dotatate? (a) 68 min (b) 78 h (c) 6 h (d) 110 min 23. Recommended dose for imaging with Ga-68 dotatate? (a) 10 mCi (b) 15 mCi (c) 20 mCi (d) 0.054 mCi/kg up to 5.4 mCi 24. Gallium-68 is ___________ produced. (a) Generator (b) Cyclotron 25. Gallium-68 dotatate is indicated for imaging what type of cancers utilizing PET? (a) Small-cell lung cancer (b) Neuroendocrine tumors (c) Prostate cancer (d) Breast cancer 26. Recommended dose for imaging with F-18 fluciclovine? (a) 10 mCi (370 MBq) (b) 5 mCi (c) 20 mCi

Appendix 15 Answers to Chapter 15

1. (d) 131I is used to treat thyroid cancer and hyperthyroidism by ablation. Grave’s disease is the most common cause of hyperthyroidism. 2. (a) The intramuscular injection of nonradioactive B12 is given to preload the liver and to saturate receptor sites in plasma so that the portion of radioactive B12 absorbed will be passed through the urine. 3. (d) 32P chromic phosphate is a bluish green colloid and is used for intracavitary therapy. 32P sodium phosphate is a clear solution that is used to treat polycythemia vera and bone pain from metastasis and is administered intravenously. 32P is a beta emitter. 4. (b) As with all radioactive materials, 89Sr should be assayed prior to administration. However, the NRC allows administration of 89Sr unit doses without assay because not all dose calibrators assay them accurately. 5. (b) See explanation for question 3. 6. (c) 32P chromic phosphate is useful in treating malignant ascites. 32P sodium phosphate is used to treat polycythemia vera. 89Sr (as well as 32P sodium phosphate and 153Sm-EDTMP) is used to treat malignant bone pain by localizing where there is bone mineral turnover. 131I may be used to treat Grave’s disease. 7. (c) 89Sr chloride can be administered by direct venous access, but as it is a beta emitter, it is a better option to access the vein with an intravenous line and check the patency of the system before injection. If the dose is infiltrated into the tissue surrounding the vein, the tissue will be unnecessarily irradiated. 8. (b) 89Sr and 32P are beta emitters and will be effectively shielded with the plastic syringe. Using a lead syringe shield will cause bremsstrahlung. 9. (b) See explanation to question 6. 10. (b) Intrinsic factor is a glycoprotein. It is secreted by the gastric mucosa, and without it vitamin B12 cannot be absorbed. If a Schilling test shows a B12 deficiency, the test can be repeated with the intrinsic factor to determine if the lack of it is the cause of malabsorption. 11. (b) The radioactivity in the urine represents the amount of vitamin B12 absorbed. The labeled B12 is excreted through the urine, so if any urine is not collected, the percent excretion will be falsely low. 12. (c) The results from the first 24-h sample collected during Stage I are abnormal (normal is >8–10%), and the result from Stage II is 12%, which is normal. This indicates that the addition of intrinsic factor has corrected the malabsorption, meaning the patient has pernicious anemia, which is a vitamin B12 deficiency resulting from lack of intrinsic factor. There are other causes of B12 which include low intake, pancreatic insufficiency, and various medications. 13. (d) To calculate the percent excreted, one uses the following formula:

Appendix 2 Answers to Chapter 2

1. (b) 201Tl decays by electron capture with gamma emissions of 0.135 MeV and 0.167 MeV. 2. (c) Stannous chloride is a reducing agent which changes the valence state of Tc in pertechnetate. It has no effect on either the amount of Al3+ or the radiation dose. 3. (b) The half-life of 131I is 8.06 days. Since the time elapsed is about two half-lives, the original activity would be halved twice (50 mCi/2 = 25 mCi, 25 mCi/2 = 12.5 mCi). 4. (b) 20 mCi × 0.62 = 12.4 mCi 5. (d) To find the effective half-life, we use the formula