Work CT

Question 1

Through explanation of CT procedure & proper communication with pt is vital in ensuring that:

Answer 1

• breathing instructions are followed.
• misregistration doesnt occur.
• pt anxiety is kept at a minimum.

Question 1

The lumen of needles used for injection of contrast media varies in diameter. The unit used to describe this diameter is called:

Answer 1

Gauge.

Question 2

Direct contraindications to contrast material administration includes;

Answer 2

• prior life threatining reaction to contrast material.
• multiple myeloma.

Question 3

What method is used to verify patient identity?

Answer 3

Check wrist band.

Question 4

What are the advantages of automatic power injectors over manual bolus method of IV contrast administration?

Answer 4

• Increased tissue enhancement due to faster injection time.
• Uniform contrast administration are entire length of the study.

Question 5

What interactions b/t x-ray beam and matter result in the largest amount of pt dose?

Answer 5

Photoelectric effect.

Question 6

Examples of mild adverse reactions to contrast may include:

Answer 6

Nausea and warm flushed sensation.

Question 7

What CT procedures require a pt to give informed consent?

Answer 7

any invasive procedure
ex: abdomen scan w/ IV contrast.

Question 8

Medication given to sedate small kids ungoing CT exams:

Answer 8

Chloral hydrate.

Question 9

Difference b/t ionic and nonionic contrast?

Answer 9

Non-ionic contrast media have a lower osmolality than ionic media.

Question 10

What term describes an IV injection of medication or contrast agent in one complete dose over a short period of time?

Answer 10

Bolus.

Question 11

Intrathecal injection before a lumbar spine place iodinated contrast material directly into what?

Answer 11

Subarachnoid space.

Question 12

Abnormalities of the middle and inner ear may best be demonstrated using CT sections of what? (mm)

Answer 12

1-2mm

Question 13

Prior to an IV injection of iodinated contrast material, the pt should be question regarding (pick 1 or more answers)
1. renal function.
2. allergic history.
3. cardiac history.

Answer 13

1, 2, and 3.

Question 14

What is used to determine the biologic effect of IV contrast media, what term refers to the # of ions formed when a substance dissociates in solution?

Answer 14

Osmolality or osmotic concentration
- described as # of particles in solution per kilogram of water.

Question 15

What laboratory values can be used to evaluated the renal function of the pt?

Answer 15

Blood Urea Nitrogen (BUN) and Creatinine.

Question 16

What infection is acquired by a pt during their stay in a health care institution?

Answer 16

Nosocomial.

Question 17

During CT exams, pts should be shielded above + below b/c of what?

Answer 17

Rotational nature of xray tube cause pt to get exposure from all sides.

Question 18

Which of the following would be best suited for IV injection of contrast material with a power injection?
A. Butterfly needle.
B. Central venous line.
C. 23-gauage spinal needle.
D. Angiocatheter.

Answer 18

D. Angiocatheter.

Question 19

What contrast material may be described as one that does not dissociate into charged particles in solution?

Answer 19

Non-ionic.

Question 20

What technical factors exhibits a direct effect on pt dose?

Answer 20

Milliampere-seconds (mAs).

Question 21

Which of the following injection control techniques is required at the site of an IV injection of iodinated contrast media?
A. Contact isloation.
B. Surgical asepsis.
C. Medical asepsis.
D. Enteric precuations

Answer 21

B. Surgical asepsis.

Question 22

Retrospective image reconstruction facts

Answer 22

• algorithm, matrix size, and DFOV may be changed.
• scan (raw) data must be available.
• restrospective image recon may be used to adjust center of displayed image.

Question 23

spiral resolution of a CT exam using the following parameters? Large focal spot, 10 mm sections, 512x512 mm matrix?

Answer 23

• change focal spot size.
• perform 5 mm sections.

Question 24

What reduces scatter radiation reaching the detecors?

Answer 24

Post-patient & predetector collimation

Question 25

What mathematical techniques used exclusively for image recon with spiral CT scanners?

Answer 25

Interpolation.

Question 26

Pixles whose average coefficients are less than that of water have what types of CT # value?

Answer 26

NEGATIVE.

Question 27

What technical parameters would greatly improve the quality of studies requiring multiplanar reformats?

Answer 27

Overlapping scans with narrow section thickness.

Question 28

Quality control measurements to test accuracy and calibration of scanner should be performed?

Answer 28

Daily.

Question 29

When an operator reduces the SFOV for a particular body part, what technical changes occur?

Answer 29

Smaller # detectors are activated.

Question 29

Average CT # for blood is:

Answer 29

+45 HU.

Question 29

What type of gas is commonly used for gas ionization CT detectors?

Answer 29

Edge gradient

Question 29

PT collimation fact

Answer 29

Prepatient colimation directly controls slice thickness.

Question 30

Increasing the pitch during a spiral CT exam adversely affects the spatial resolution along with:

Answer 30

Z-axis.

Question 31

Simple cysts of the kidney have average attenuation values in the range of:

Answer 31

0 to 20 HU.