SP12:Oncologic Scintigraphy Flashcards
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)
(e) Because any infiltrated dose may cause uptake in the axillary nodes, the injection should be made through an indwelling catheter and in the arm contralateral to the suspected abnormality. If there is infiltration, this information should be made available to assist image interpretation.
What is the optimal scanning time for neoplasm when using 67Ga citrate?
(a)4 h
(b) 6 h
(c) 24 h
(d) 48 h
(d) 67Ga has a half-life of 78 h, and so imaging can take place over several days. Imaging for infection is often performed on the same day as the injection and continues at 24 h and onward at 24 h intervals. Tumor imaging is usually begun at 48 h and continued at 24 h intervals.
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
(d) Lymphoscintigraphy is performed by injecting a radiocolloid near a tumor and can be used to identify the sentinel node and lymphatic drainage from a tumor. Dynamic and delayed imaging is often used.
111In pentetreotide is a:
(a)Potassium analog
(b) Monoclonal antibody
(c) Somatostatin analog
(d) Radiocolloid
(c) Pentetreotide (octreotide) is a synthetic form of somatostatin. Somatostatin is a neuropeptide that, among other things, inhibits the secretion of growth hormone. Somatostatin receptor imaging is performed for the detection of neuroendocrine and some non-neuroendocrine tumors with high density of somatostatin receptors. These are often tumors that originate from somatostatin target tissue. Examples of cancers that express somatostatin receptors are pancreatic islet cell tumors, certain brain tumors, pituitary adenoma, gastrinoma, small cell lung cancer, pheochromocytoma, medullary thyroid carcinoma, some breast cancers, and lymphomas.
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.
(b) HAMA stands for human antimurine (aka antimouse) antibody. It is a response that the human immune system may mount against a foreign antigen.
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
(d) All radiopharmaceuticals should be assayed and emission appropriate shielding should be used. In addition, 111In satumomab pendetide should be filtered before injection because it is a protein and has the potential for particle formation.
111In satumomab pendetide is used to image:
(a)Extrahepatic metastases from colorectal and ovarian cancer
(b) Breast tumors
(c) Neuroendocrine tumors
(d) Lymphatic channels
(a) 111In satumomab pendetide is a monoclonal antibody that allows tumor imaging because it binds to certain tumor antigens. It is used most commonly in colorectal and ovarian cancers.
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.
(e) Bothe 201Tl and 67Ga citrate can be used to image lymphoma, but 67Ga citrate may be taken up in infection, and there is a longer delay before imaging. However, 201Tl has less sensitivity for detecting small lesions. They have comparable half-lives.
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
(b) There is low-intensity, homogenous uptake of 99mTc sestamibi in normal breast tissue.
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.
(b) Antibodies are proteins that are produced in response to the presence of an antigen, and they bind to that antigen. Cross-reactivity means a reaction to a similar but different antigen.
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
(d) Neuroendocrine tumors have been called apudomas (taking the first letters from amine precursor uptake and decarboxylation) or tumors arising from APUD cells. (APUD cells secrete polypeptides, amines, or both.) The neuroendocrine system compromises the nervous system and the endocrine glands and the interactions between the two. Examples include carcinoids, small cell lung cancer, pituitary adenomas, pheochromocytomas, some brain tumors, and islet cell tumors.
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
(a) Genitourinary activity may be seen even on delayed images obtained with 111In pentetreotide. It is not normally seen on delayed images (>24 h) obtained using 67Ga citrate.
18FDG can be used to image tumors because the glycolytic rate is higher in tumor than in normal tissues.
(a)True
(b)False
(a) 18FDG uptake in tumors is due to their high glycolytic rates. Poorly differentiated tumors have greater uptake than well-differentiated tumors; this is the reason that he standard uptake value (SUV) has prognostic value.
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.
(e) 18F is a positron emitter. 18FDG is a glucose analog that is taken up preferentially in many tumor types due to their higher glycolytic rates. Patients should fast in preparation for the exam because hyperglycemia can reduce tumor uptake of 18FDG.
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.
(c) Studies involving barium in the week prior to the exam can interfere with visualization. Additionally gadolinium, when used within 24 h of gallium injection, may decrease localization of gallium. Chemotherapy can also negatively affect the uptake of gallium; scans should be performed at least 3 weeks after chemotherapy.
