Unit 1: Computed Tomography Generations (review)

The correct terminology to describe present day CT is __________.

Computed Tomography

Which terms are associated with seventh generation spiral-helical technology?

multisection scanner multidetector scanner multiple detector array scanner

Does the CT x-ray tube have a higher power capacity than the general radiography x-ray tube?

no, they are very similar

What determines section thickness in a seventh generation scanner?

width of the detector

Which generation of CT scanners was the first to use a curved array of rotating detectors?

3rd generation

What generation of CT scanner was designed specifically for cardiac imaging?

5th generation

Which generation of CT scanners is associated with the term "EBCT" and the use of an electron beam gun?

5th generation

CT scanner x-ray tube voltages range from __________ to __________ kilovolts (kV).

80, 140

What is the main purpose of the slip ring technology?

- permits continuous supply of power to x-ray tube while it rotates 360 degrees - eliminates power cables

Fourth generation scanners may have scanning times as short as __________ second(s).

.5 - 10

What was the degree of rotation for a first generation scanner and how many translations/rotations did it take to complete one scan?

1 degree rotations, 180 times

How many exams must be documented to qualify to take the CT post-primary certification exam?

125

The term "translation" is associated with __________ generation scanners.

1st & 2nd

Which generation of scanners used water bags?

1st generation

What was the source of radiation used in Hounsfield's first primitive CT scanner?

Americium

Fifth generation scanners were sometimes referred to as __________.

Electron Beam Tomography (EBT)

Who were the winners of the 1979 Nobel Peace Prize in Physiology or Medicine?

Godfrey Hounsfield and Allan Cormack

The seventh generation scanner is also called:

Multisection or Multislice CT (MSCT)

The gantry contains an opening for the patient. What is the opening called?

aperture

A CT gantry includes all of the following components EXCEPT: a. collimators b. detectors c. central processing unit d. bow tie filters

central processing unit

Which type of x-ray beam geometry is used by modern, multidetector CT scanners?

cone beam

Which plane divides the body into an anterior and posterior portion?

coronal plane

Fourth generation scanners used which type of detectors?

curved, nonrotating

What is the primary difference between a CT x-ray tube and radiography x-ray tube?

designed to handle and dissipate excessive heat units (about twice the amount as radiography tubes)

A 5th generation CT scanner is a real time __________ scanner.

dynamic

Second generation scanners used what type of beam & detectors?

fan beam, multidetectors

What principle advantage does the 2nd generation scanner have over the first generation scanner?

faster speed

The system that houses the x-ray tube and detectors is the __________.

gantry

What did first generation scanners image?

head and brain

Seventh generation CT scanners have __________ acquisition to acquire data while the table is moving (indexing).

helical

First generation CT scanners used __________ beam scanning.

pencil

The extension or contraction of the helix is called __________.

pitch

What types of collimators are used in computed tomography machines?

prepatient and postpatient (predetectors)

When compared to the third generation scanners, what do the fourth generation scanners avoid?

ring artifact problems

What causes the ring artifact in the 3rd generation scanner?

single detector array (due to a faulty or improperly calibrated detector)

All power to the gantry of a spiral-helical CT scanner is conveyed via:

slip rings

Spiral-helical CT scanning is based on __________ and __________.

slip-ring technology, volume data acquisition

What determines the weight limit of a CT table?

the maximum load to which the table can be moved accurately

In sixth generation CT scanners, what rotates around the patient?

x-ray tube and detectors

Are tube and detector alignment important in CT?

yes