Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

From Flashcardlet > specials tomography > Flashcards

specials tomography Flashcards

0
Q

Body section radiography

A

Technical procedure in which any selected plane body is depicted distinctly by moving film and X-ray tube in opposite directions to blur structure above and below that plane. Aka plangiography, laminography, strtoegraphy, tomography

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

Amplitude

A

Distance the X-ray tube travels during the exposure in tomo

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Exposure angle

A

Angle created by the amplitude and fulcrum during tomography

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Focal plane

A

Selected level or layer which remains in maximum focus in relation to tube and film throughout movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Fulcrum

A

Adjustable axis of rotation about which the X-ray tube and film move in opposing directions

Aka pivot point

Where anatomy looks best

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Linear streaking

A

Incomplete blurring of a structure, produced when that structure parallels the direction of tube

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Linear tomography

A

Type of body section radiography utilizing a straight line tube film motion only

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Movement pattern

A

Direction of X-ray tube movement during a tomographic procedure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Multidirectional tomography

A

Type body section radiography utilizing tube film motion in many directions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Pivot point

A

Axis rotation of the X-ray tube and film

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Rate of tube travel

A

Speed at which X-ray tube moves during tomography , measured in inches per second

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Right angle blurring

A

Blurring produced by moving X-ray tube and film at right angles to the structure being examined

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Tomography

A

Procedure which allows to record only selected layers within body free from superimposition shadows of other organs and tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Equipment

A

Means moving X-ray tube in controlled direction

Linking X-ray tube tonbucky tray , so that film is placed in tray will be simultaneously driven an equal distance in opposite direction

Means of varying the height of fulcrum or pivot point of movement , so that different anatomical levels or layers in patient may be examined

Mechanical stability , to prevent unsharpness arising in fulcrum plane as result of vibration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Principles of tomo

A

Metal lever connects the X-ray tube carriage and film tray. Provides means for moving them in opposite directions at coordinated speeds about an adjustable pivot or fulcrum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Fulcrum

A

Point at which no blurring occurs

Sometimes referred as focal plane

Adjustable from table top to about 25 cm above table

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Adjusting the hight of fulcrum we can selectively bring into focus any desired tissue layer

A

.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

The shadows of selected layer called focal plane - move in same direction and same speed as film - so they maintain a constant relationship with coinciding point of film and therefore defined

A

.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Shadows of structures lying above and below fulcrum move in direction as film but different speeds , so they are out of focus. Cast blurred image on film

A

.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Thickness of Tomo sections appear sharp focus determined

A

Length or angle tube travel during exposure

Sid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Wide angle tube movement ( over 10 degrees) produce thin section

A

.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Narrow angle of tube movement (less that 10 degrees) produce thick sections

A

.

22
Q

Longer the amplitude
Wider exposure angle
Thinner the section

A

.

23
Q

Shorter amplitude
Narrower exposure angle
Thicker section

A

.

24
Q

Sid

A

Effects thickness

25
Q

Sid decreases the ankle of tube at extreme end of its amplitude will increases resulting in more blurring and consequently a thinner section

A

.

26
Q

Two methods changing fulcrum height

A

Planographic principle

Gross man principle

27
Q

Planographic principle

A

Fulcrum or axis of rotation is raised or lowered to alter the level of focal plane( table top height remains constant)

28
Q

Gross man principle

A

Fulcrum or axis of rotation remains at fixed height. Focus plane level changed by raising or lowering the tabletop through fixed point to desired height( fixed fulcrum)

29
Q

Blurring motion

A

Unidirectional or linear one direction

Multidirectional or plurieirectional or complex motion

30
Q

Linear or unidirectional motion

A

Most common body tomo in use- usually attaches to existing radiographic unit- cheap less expensive

31
Q

Tube film motion linear

A

.

32
Q

Film moves same oath but in opposite direction of tube

A

.

33
Q

Tomographic angle or exposure angle 10 to 50 degrees

Short exposure- less radiation to patient

2 sec minimum tomo time

A

.

34
Q

Disadvantage to linear tomo

A

Restriction length of tube travel

Linear streaking ( parasite streaks, phantom images) since tube and film move in straight parallel lines shadows rod like objects , parallel to direction of tube motion , even though out focus may by produced on xray

Linear streaking can be controlled by adjusting the patient as place long axis of unwanted structures at either a right angle or a 35-40 degree angle to direction tube movement

Maintains mechanical stability and vibration

Tube centered and body alignment also problem

35
Q

Different tube movements

A

Linear - 2 secs

Circular
- 3 sec
Elliptical

Spiral- 6 sec

Figure 8- 8 sec

Hypocycloiddal- 6sec

36
Q

As motion of tube and film become complex the blurring capability and cost of unit increased

A

.

37
Q

Specially designed Bucky diaphragm causes grid to adjust automatically by rotation around central ray

A

.

38
Q

Multidirectional movements eliminate the problem of streaking by producing blurring in all directions

A

.

39
Q

Extent blurring , length and time of tube travel increases as complexity of tube movement increases

A

.

40
Q

Advantages

A

Max control scatter
Better blur effect than linear movements
Total tomo angle can be increased over linear length of tube travel increased by means of circular path traveling
Unit performs standard diagnostic X-rays

41
Q

Zonography

A

Relatively thick sections

Exposure angle is less than 90 degrees

Serves scout film

Utilized to remove a lesion from its surrounding , whereas tomography enables the beholder to see into that lesion

42
Q

Basic principles

A

.

43
Q

Thre prelim Tomis are taken to locate correct levels for tomo

A midpoint images, and one above and below midpoint

A

.

44
Q

Two or more projections are required for most tomo

A

.

45
Q

Ap and lateral projections are basic

A

.

46
Q

Structures examined should be orie ted either parallel or perpendicular to tomo plane

Parallel - base of skull, long bones

Perpendicular - sella turcica

A

.

47
Q

Know anatomy involved

A

General body aorta location

How best position of structure

Depth and location of particular structure

How tomo image shoud look

48
Q

Position patient precise

A

.

49
Q

Small focal spot for head, neck, extremities

A

.

50
Q

Large focal spot for all other body where fine detail not critical

A

.

51
Q

Low KVp when high contrast

A

.

52
Q

Collimate reduce patient exposure and increase contrast

A

.

53
Q

Shield eyes and rest body

A

.

From Flashcardlet (57 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions