Getting To Know CT

Question 1

In 1901, who was awarded the first Nobel Prize in Physics?

Answer 1

Wilhelm Conrad Röntgen for the discovery of x-rays

Question 2

What were some reasons to develop tomographic imaging techniques?

Answer 2

Conventional radiographs superimposed anatomy
Conventional radiographs are limited in their ability to show the difference between tissues with similar densities
Physicians wanted to be able to see inside a patient in a manner similar to surgical exploration

Question 3

What were used in tomographic systems before the first CT scanners existed?

Answer 3

Film

Question 4

Conventional tomography was NOT clinically useful because:

Answer 4

Images were often too blurry
Took too long to make an image
Images lacked detail

Question 5

Detectors were incorporated into CT scanner designs to replace film because detectors:

Answer 5

Converted the x-ray attenuation information into an electrical signal which could be used by a computer

Question 6

When was the first commercial CT scanner available?

Answer 6

1970s

Question 7

A thick x-ray beam that not only spreads to the sides of the patient table but also diverges along the length of the patient table

Answer 7

Cone Beam

Question 8

MDCT scanners were first attempted by:

Answer 8

EMI in the 1970s

Question 9

What kind of information can be obtained with PET/CT?

Answer 9

Images with metabolic information (PET)
Images with high-resolution anatomical information (CT)
Attenuation correction

Question 10

Which cross-sectional orientations of an abdomen can be directly scanned in CT?

Answer 10

Transverse

Question 11

What’s the difference between CT and conventional radiography?

Answer 11

Cross-sectional slices

Digital modality

Question 12

Arrange MR imaging, CT imaging, and plain film x-ray imaging in order from best to worst in their ability to differentiate soft tissues in the body

Answer 12

MRI > CT > X-ray

Question 13

What is the set safe level of exposure to ionizing radiation?

Answer 13

None, must be as low as possible given the clinical goal

Question 14

Which imaging modalities uses ionizing radiation?

Answer 14

Any modalities using x-rays (conventional radiography, mammography, computed tomography)

Question 15

In the oncology department, CT may be used to:

Answer 15

Collect an image used for therapy planning
Verify patient and tumor position prior to therapeutic radiation
Initially diagnose presence of malignancy

Question 16

What can be found in the nucleus of an atom?

Answer 16

Protons and neutrons

Question 17

The x-ray beam produced by a CT x-ray tube is composed of what type of radiation(s)?

Answer 17

Almost 100% bremsstrahlung radiation

Question 18

The extent of the attenuation of an x-ray beam is dependent upon:

Answer 18

Energy of the x-ray photon
Atomic number of the atoms in the tissues penetrated by the beam
Density of electrons of the atoms in the tissues

Question 19

A dense structure will attenuate an x-ray beam _____ than a structure that is not dense.

Answer 19

More

Question 20

What is the most common type of film used for recording CT images?

Answer 20

Single emulsion (CT laser film)