Deck 22: Computed Tomography Simulation

Question 1

2)A CT scanner specifically designed for use in the radiation therapy department should have which characteristics?
I)High performance scanner
II)Laser and patient marking system
III)Virtual simulation capabilities

A) I and II
B) I and III
C) II and III
D) I, II, and III

Answer 1

D
The treatment field must be precisely localized and verified during the simulation process to accurately deliver the dose.To do this, the system must have a keen visualization system, a laser and patient marking system, and the ability to define and create the parameters for treatment.

Question 2

11)When using intravenous (IV)contrast to enhance the anatomy of the brain, the best interval for contrast administration should be before the scan by _____________.

A) 30 seconds
B) 60 seconds
C) 30 minutes
D) 60 minutes

Answer 2

C
To enhance vascular of the brain, IV contrast is administered 10 to 30 minutes prior to the scan through an IV push.

Question 3

5)Of the following list of contrast agents, which is not water soluble and therefore should not be used in the gastrointestinal tract if there is an increased risk of perforation?

A) High-osmolality contrast
B) Low-osmolality contrast
C) Gastrografin
D) Barium sulfate

Answer 3

D
Barium sulfate is commonly used to differentiate the gastrointestinal tract; however, it would not be used for patients with a high risk of gastrointestinal perforation because it is not water soluble.

Question 4

1)What is a maximum intensity projection, or MIP?

A) Measurement of table translation
B) Result of noise on an image
C) Relationship between the matrix size and the pixel size on an image
D) Fused scan that shows the maximum amount of tumor movement during the respiratory cycle

Question 5

6)The reconstructed field of view that is displayed on the computer monitor should be large enough to display which of the following?
I)Entire contour
II)Immobilization device
III)Pertinent anatomy only

A) I
B) II
C) III
D) I and II

Question 6

4)Of the four methods by which contrast media may be introduced into the body, which are the most common in CT simulation?
I)Oral
II)Intrathecal
III)Intravascular
IV)Intra-articular

A) I and II
B) I and III
C) II, III, and IV
D) I, II, and IV

Question 7

3)Which of the following are benefits of CT simulation?
I)The ability to outline critical structures and view these structures in three dimensions
II)Machine setup parameters and treatment accessories unable to be verified on the CT scanner
III)Virtual simulation allows for construction of digitally reconstructed radiographs DRRs without the patient being present

A) I and II
B) I and III
C) II and III
D) I, II, and III

Question 8

10)A contraindication for administering barium-based contrast to a patient with a history of long-term steroid therapy would be an increased risk of _______________.

A) aspiration
B) colon perforation
C) difficulty in holding an enema
D) allergic reaction

Question 9

7)Which of the following is the window width on a CT image?

A) The range of numbers displayed on a CT image
B) The number of columns and rows of pixels demonstrated on an image
C) An unwanted image characteristic
D) The central Hounsfield unit of all the CT numbers displayed on an image

Question 10

9)Image registration or fusion has all of the following characteristics except which of the following?

A) It ensures that the patient is in the same position for all scans.
B) It identifies preoperative volume.
C) It is useful for determining the extent of the tumor.
D) It uses two sets of images that are similar.

Question 11

8)Which of the following is the window level on a CT image?

A) The range of numbers displayed on a CT image
B) The number of columns and rows of pixels demonstrated on an image
C) An unwanted image characteristic
D) The central Hounsfield unit of all the CT numbers displayed on an image