Question 1

At the time of a PET scan, ideally the blood glucose level should not be above&#10;A) 60 mg/dL.&#10;B) 100 mg/dL.&#10;C) 120 mg/dL.&#10;D) 180 mg/dL.

Accepted Answer

The peripheral blood glucose level can be measured with a glucometer. Ideally, the value should be less than 120 mg/dL. Increased blood glucose levels can compete with FDG, resulting in little difference between tumor and normal soft tissue uptake as well as very low-contrast images.

Question 2

Standard uptake values (SUVs) are useful in distinguishing between benign and malignant disease.

Accepted Answer

SUVs cannot distinguish between benign and malignant diseases with any helpful degree of accuracy because, as mentioned previously, common fungal and infectious processes can use FDG at very high rates and bronchoalveolar cell carcinoma or other low-grade tumors can use FDG at background levels.

Question 3

When imaging lymphomas, PET&#10;A) can distinguish between scar tissue and residual tumor after therapy.&#10;B) is comparable to CT in distinguishing scar tissue and residual tumor after therapy.&#10;C) is comparable to MRI in distinguishing scar tissue and residual tumor after therapy.&#10;D) is not involved in staging but is involved in therapy evaluation.

Accepted Answer

PET outshines all other anatomic imaging modalities in the evaluation of lymphomas (especially in the evaluation of the therapeutic response), because neither CT nor MRI can distinguish between scar tissue and residual tumor after therapy. Persistent FDG tumor activity after therapy strongly suggests residual or recurrent tumor. Lack of FDG activity essentially excludes persistent tumor, especially if FDG activity was present on the pretherapy examination.

Question 4

Brain tumors are easily identified with FDG imaging.

Accepted Answer

Because the normal cerebral and cerebellar neurons use FDG avidly, primary and metastatic brain tumors can be, and are, missed. Figure 15-26 shows a brain tumor that cannot be identified with FDG imaging.

Question 5

An inpatient who is receiving total parental nutrition is scheduled for PET exam at 3:00 PM. Those responsible for his care should&#10;A) discontinue the feeding 2 hours before the study.&#10;B) discontinue the feeding 4 hours before the study.&#10;C) discontinue the feeding 6 to 8 hours before the study.&#10;D) not have to discontinue this type of feeding.

Accepted Answer

If the patient is receiving dextrose solution or total parental nutrition, it should be discontinued 6 to 8 hours prior to the injection of the ¹⁸F-FDG. This is so that competition for binding sites does not occur between the radioactive sugar analog used in PET imaging and sugar compounds in these items.

Question 6

Which of the following diagnoses requires a head-to-toe PET scan?&#10;A) Lymphoma&#10;B) Melanoma&#10;C) Colorectal cancer&#10;D) Mesothelioma

Accepted Answer

Any patient with a history of melanoma, even if referred for another indication, should have a total (head-to-toe) body scan.

Question 7

FDG enters cells by means of&#10;A) active transport.&#10;B) phagocytosis.&#10;C) facilitated diffusion.&#10;D) capillary action.

Accepted Answer

Both glucose and FDG are absorbed by facilitated diffusion into cells, with the assistance of certain specific membrane transport proteins.

Question 8

Which type of testicular tumor avidly takes up FDG?&#10;A) Seminoma&#10;B) Mature teratoma&#10;C) Non-seminoma&#10;D) Adenoma

Accepted Answer

Testicular cancers, especially seminomas, avidly take up FDG.

Question 9

If an injection of contrast media is going to follow an injection of FDG, the technologist should use&#10;A) a butterfly needle to inject.&#10;B) an 18- to 20-gauge intracatheter.&#10;C) an indwelling central catheter.&#10;D) a port-a-cath.

Accepted Answer

If the patient is going to have iodinated contrast along with the PET/CT exam, an 18- to 20-gauge intracatheter should be used for FDG injection and then kept for use with the contrast media. Residual measurements for FDG in the injecting apparatus will not be possible, so it is imperative that proper injection technique is used. A 20- to 30-ml saline flush after the FDG injection helps to reduce venous FDG uptake in the upper extremity. Port-a-caths or indwelling central catheters should not be used to inject FDG unless absolutely necessary.

Question 10

PET has proved to be effective as a screening tool for colorectal cancers.

Accepted Answer

PET is a superb, cost-effective screening tool for colorectal cancers, mainly because it identifies more sites of tumor involvement and more accurately determines nonresectable disease, thereby avoiding unnecessary and more costly surgical procedures.

Question 11

In the United States, breakthrough reimbursement for PET scans was determined by the&#10;A) U.S. Department of Health and Human Services (DHHS).&#10;B) Centers for Medicare and Medicaid Services (CMS).&#10;C) Centers for Disease Control and Prevention (CDC).&#10;D) U.S. Food and Drug Administration (FDA).

Accepted Answer

The answer of In the United States, breakthrough reimbursement for...

Question 12

Once the intravenous line is started for the FDG injection, the patient should&#10;A) relax for 10 minutes and refrain from talking.&#10;B) be positioned for imaging.&#10;C) have a blood glucose level measured.&#10;D) be instructed to return to the department in 1 hour for the procedure.

Accepted Answer

The answer of Once the intravenous line is started for...

Question 13

In head and neck imaging, normal variants, such as salivary gland uptake and lingual, buccal, pharyngeal, laryngeal, and neck muscle activity, can cause diagnostic difficulties.

Accepted Answer

The answer of In head and neck imaging, normal variants,...

Question 14

Which anatomic areas present with normal variations in FDG localization?&#10;A) Mouth and salivary glands&#10;B) Myocardium of the left ventricle&#10;C) Extraocular muscles&#10;D) All of these

Accepted Answer

The answer of Which anatomic areas present with normal variations...

Question 15

Once in the cell's cytosol, FDG adds a phosphate group and proceeds with further transformation. This change in FDG results in&#10;A) conversion of FDG to glucose.&#10;B) release of FDG from the cell.&#10;C) FDG becoming trapped in the cell.&#10;D) removal of FDG from the cytosol.

Accepted Answer

The answer of Once in the cell's cytosol, FDG adds...

Question 16

The use of ¹⁸F-fluorodeoxyglucose (FDG) in cancer imaging is based on the fact that A) tissue cells surrounding tumors use glucose at a faster rate than normal cells. B) cancer cells use glucose at a faster rate than normal cells. C) it is specific for distinguishing between benign and malignant diseases. D) necrotic cells use glucose at a faster rate than normal cells.

Accepted Answer

The answer of The use of ¹⁸F-fluorodeoxyglucose (FDG) in cancer...

Question 17

Patient preparation for a PET scan includes all of the following EXCEPT&#10;A) avoidance of strenuous exercise for 24 hours before the study.&#10;B) rest prior to, during, and after injection.&#10;C) keeping baseline metabolic activity low.&#10;D) eating a meal just prior to scanning because of the time involved with the study.

Accepted Answer

The answer of Patient preparation for a PET scan includes...

Deck 15: Clinical Petct in Oncology