Image Production

Question 1

For a given ct acquisition the calculated mas applied to each reconstruction slice may be referred to as

Answer 1

Effective mas

Question 2

When using a 3rd generation ct scanner it is important that reference detectors positioned at the peripheral portions of the detector array be exposed to

Answer 2

Unattenuated radiation

Question 3

What two scientists got the Nobel prize in 1979

Answer 3

Hounsfield and cormack

Question 4

Which of the following terms accurately describes the type of Xray beam used in a 3rd gen ct scanner

Answer 4

Fan beam

Question 5

Decreased mas will do what to patient radiation dose

Answer 5

Decrease

Question 6

In MSCT the beam pitch is equal to the table feed per rotation divided by the

Answer 6

Total collimation

Question 7

In an MSCT system the detector array is composed of multiple rows of individual detector elements along the

Answer 7

Z-axis

Question 8

The type of MSCT detector array that contains midline narrow elements flanked by wider detectors is called

Answer 8

Hybrid array

Question 9

The process of scanning a phantom device of known density to improve the accuracy of CT attenuation measurement is

Answer 9

Calibration

Question 10

Which of the following types of image reconstruction was used in the first prototype ct scanner

Answer 10

Iterative technique

Question 11

Ct images that have been reconstructed from a portion of the data acquisition process in the hopes of reducing pt motion artifacts are called

Answer 11

Segmented images

Question 12

As a solid state ct detector measures transmitted radiation it emits a proportional response in the form of

Answer 12

Analog signal

Question 13

During a ct scan each sample of ray sum measurements made by the data acquisition system DAS is called

Answer 13

View

Question 14

The ability of an object to attenuate the Xray beam is assigned a value known as

Answer 14

Linear attenuation coefficient

Question 15

The primary advantage of an isotopic MDCT data set is

Answer 15

High quality multiplanar reformations

Question 16

The technique that allows the user to select the range of pixel values used in a 3D ct reformation is termed

Answer 16

Thresholding

Question 17

—— is part of 3D image processing

Answer 17

Surface rendering

Question 18

How much oral contrast

Answer 18

750-1500 mls

Question 19

C spine images require slice thickness of

Answer 19

1mm

Question 20

—-mm required to create lower extremity reformats

Answer 20

2mm

Question 21

Type —— dissections affect the ascending aorta

Answer 21

A

Question 22

What is a coagulopatgy bleed

Answer 22

Head bleed caused from blood thinners

Question 23

What causes a amyloid headache bleed

Answer 23

Abnormal buildup of protein A disease that may be heritage and causes person to have spontaneous small vessels to burst

Question 24

What is the main part of the CT’s computer system

Answer 24

Array processor

Question 25

What is pitch

Answer 25

The distance the table travels during 1 revolution

Question 26

Pitch ratio is

Answer 26

When the tube revolution equals the slice thickness is 1:1

Question 27

Filament size has an impact on

Answer 27

Special resolution

Question 28

—- is the ability to distinguish between objects that differ in density

Answer 28

Special resolution

Question 29

—- detectors are used used primarily in 3rd gen scanners

Answer 29

Gas ionization

Question 30

Voxel size depends on

Answer 30

Slice thickness (z axis)

Question 31

MIP uses

Answer 31

Volume rendering

Question 32

Volume rendering uses data from a

Answer 32

2d projection to produce a 3D image

Question 33

A volume of tissue or volume element is a

Answer 33

Voxel

Question 34

The z axis is

Answer 34

Longitudinal

Question 35

Perfect image has a

Answer 35

1.0

Question 36

Imperfect image has

Answer 36

0.1

Question 37

The Y axis is the

Answer 37

AP image or up and down

Question 38

The frequency response to create an image

Answer 38

MTF

Question 39

HU number for hepatic cysts

Answer 39

0-20

Question 40

HU number for normal brain

Answer 40

15-22

Question 41

HU for muscle

Answer 41

50

Question 42

HU for air

Answer 42

-600 to -1000

Question 43

PET scans measure

Answer 43

The uptake of PDG

Question 44

— area of the pt that is exposed to radiation

Answer 44

Dose profile

Question 45

FWHM is a measure of

Answer 45

Effective section width

Question 46

Accounts for dose in the X Y and Z axis

Answer 46

CTWI vol

Question 47

Doesn’t matter if scan is spiral or helical

Answer 47

CTDI W

Question 48

Ct filament size

Answer 48

0.5-1.2

Question 49

Grouping together detector channels

Answer 49

Binning

Question 50

To calculate CTDI the acquisition must

Answer 50

Be contiguous

Question 51

The P way correlates to

Answer 51

Atrial systole

Question 52

The T wave correlates to

Answer 52

Cardiac diastole

Question 53

The QRS complex correlates to

Answer 53

The ventricular systole

Question 54

What is DLP

Answer 54

The total amount of exposure for an exam

Question 55

Typical kv for ct scanners

Answer 55

60-100

Question 56

Term to describe X-rays ability to ionize a volume of air

Answer 56

Exposure

Question 57

Exposure is measured in

Answer 57

Roentgens

Question 58

Amount of Xray energy absorbed in a unit of mass

Answer 58

Absorbed dose

Question 59

Absorbed dose is measured in

Answer 59

Grays

Question 60

Accounts for the type of tissue that radiation is deposited in

Answer 60

Effective dose

Question 61

Effective dose is measured in

Answer 61

Sev

Question 62

Approximate measure of dose received in a single ct slice

Answer 62

CTDI

Question 63

CTDI100 corresponds to

Answer 63

Pencil ionization chamber

Question 64

As pitch increases the dose per section

Answer 64

Decreases (CTDI VOL)

Question 65

What is displayed in all ct reports

Answer 65

DLP and CTDI

Question 66

Window width is the ———————————————

Answer 66

Range of ct numbers with in an image

Question 67

Absorbed dose is measured in

Answer 67

Gray

Question 68

Dose profile is the

Answer 68

Area of the pt that’s exposed to radiation

Question 69

MA is always increased to produce

Answer 69

Thinner images

Question 70

The peritoneum contains

Answer 70

``` Stomach Small bowel Small portion of duodenum Jejunum and ileum Transverse colon Liver Gb spleen Ovaries ```

Question 71

What is in the retroperitoneum

Answer 71

``` Duodenum Pancreas Adrenals Kidneys Ureturs Bladder Aorta. IVC prostate uterus ```

Question 72

What is in the mediastinum

Answer 72

Heart. Greater vessels Esophagus. | Trachea. Phrenic and cardiac nerves. Thoracic duct. Thymus. Central chest lymph nodes

Question 73

What is spondylosis

Answer 73

Age related wear and tear of disk | L spine

Question 74

What is spondylolysis

Answer 74

Occurs to the pars

Question 75

What is spondylolisthesis

Answer 75

One vertebral body slips over another

Question 76

A ring artifact in a ct head scan would most likely be caused by

Answer 76

A detector malfunction

Question 77

The stair step artifact of 3D aortic/heart images most likely is caused by

Answer 77

Not enough overlap