QUIZ #2 Flashcards Preview

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Flashcards in QUIZ #2 Deck (22):
1

[Collimator testing quarterly]

[_____]

[_____]

[_____]

[_____]

[Collimator Testing quarterly]

Light field - x ray field congruency

Image receptor (PBL) - x ray field congruency

Accuracy of X/Y scale

Illuminator bulb brightness

2

[Collimator testing semi-annually]

[_____]

[_____]

[Collimator testing semi-annually]

All AEC

Overload heat warning

3

[Light field- X ray field Congruency]

The [_____] of the light field to the radiation field is of great importance.

It must be within +/- [__] of the SID used

This is AKA the [_____] test

Film is placed table top and collimation is done, two pennies are lined up, so that they touch exactly where the light field ends. On all 4 sides.

Exposure is made and inaccuracies are totaled.

[Light field- X ray field Congruency]

The accuracy of the light field to the radiation field is of great importance.

It must be within +/- 2% of the SID used

This is AKA the 9 penny test

Film is placed table top and collimation is done, two pennies are lined up, so that they touch exactly where the light field ends. On all 4 sides.

Exposure is made and inaccuracies are totaled.

4

[Image receptor / X ray field Alignment]

Assures that the x-ray field is accurate to the size of a film when using [_____].

An unloaded 8X10 cassette is placed in bucky. A loaded 10 X 12 cassette is table top.

All are centered to the tube at 40” SID. Expose

If the resulting field size is 8 X 10 or less this passes, if it is more, triangulation is required to determine actual size. +/- [__] total, +/- [__] one side.

[Image receptor / X ray field Alignment]

Assures that the x-ray field is accurate to the size of a film when using PBL.

An unloaded 8X10 cassette is placed in bucky. A loaded 10 X 12 cassette is table top.

All are centered to the tube at 40” SID. Expose

If the resulting field size is 8 X 10 or less this passes, if it is more, triangulation is required to determine actual size. +/- 4% total, +/- 3% one side.

5

[Central Ray Congruency]

Ensures that center of [_____] is aligned with central ray.

Place loaded 8 X 10 cassette in tray, center tube at 40 “ SID, collimate to 4 X 6 area.
Expose

Draw line from corner to corner of film. Repeat from opposite corner. Place dot where lines intersect. Repeat for irradiated area.

Measure distance between points. Must not exceed +/- [__].

[Central Ray Congruency]

Ensures that center of bucky tray is aligned with central ray.

Place loaded 8 X 10 cassette in tray, center tube at 40 “ SID, collimate to 4 X 6 area.
Expose

Draw line from corner to corner of film. Repeat from opposite corner. Place dot where lines intersect. Repeat for irradiated area.

Measure distance between points. Must not exceed +/-1 % SID.

6

X/Y Scale- +/- [__]

Bulb Brightness- Using a photometer the illumination should be [__] ft-c or [__] lux at 40” SID.

SID indicators- +/- [__]

Overload Protection- Prevents exposure that exceeds [__] % of potential.

Heat Sensors- provides warning when [__] % capacity is reached.

X/Y Scale- +/- 2% SID

Bulb Brightness- Using a photometer the illumination should be 15 ft-c or 160 lux at 40” SID.

SID indicators- +/- 2% SID

Overload Protection- Prevents exposure that exceeds 80% of potential.

Heat Sensors- provides warning when 75% capacity is reached.

7

[Beam Alignment]

Ensures that the tube is mounted properly in housing, preventing any [_____].

The tube must be mounted within [__]-degree of perpendicular.

Testing should be done [_____].

A specific test tool is used to determine.

[Beam Alignment]

Ensures that the tube is mounted properly in housing, preventing any distortion.

The tube must be mounted within 1 degree of perpendicular.

Testing should be done annually.

A specific test tool is used to determine.

8

[Automatic Exposure Control (AEC)]

Advantage is consistent OD over range of [_____].

Uses a set intensity, once reached in detector, circuit is turned off

Density steps will increase/decrease set point changing intensity set point (mAs) only.

Back up timers are required to prevent excessive exposure to patient and tube, [__] sec or [__] mAs.

[Automatic Exposure Control (AEC)]

Advantage is consistent OD over range of patient size.

Uses a set intensity, once reached in detector, circuit is turned off

Density steps will increase/decrease set point changing intensity set point (mAs) only.

Back up timers are required to prevent excessive exposure to patient and tube, 6 sec or 600mAs.

9

[AEC Consistency Testing-mA]

AEC should adjust [_____] to maintain OD with different mA stations

+/- [__] %
+/- [__] OD

Center tube to bucky and phantom at 40” SID

Place 10 X 12 in bucky and expose, repeat four times, using different mA stations
Process and measure OD at center

[AEC Consistency Testing-mA]

AEC should adjust time to maintain OD with different mA stations

+/- 10 %
+/- 0.2 OD

Center tube to bucky and phantom at 40” SID

Place 10 X 12 in bucky and expose, repeat four times, using different mA stations
Process and measure OD at center

10

[AEC Consistency Testing-kVp]

AEC should adjust [_____] to maintain OD with different kVp settings.

+/- [__] %
+/- [__] OD

Center tube to bucky and phantom at 40” SID

Place 10 X 12 in bucky and expose, repeat four times, using 100 mA station and kVp settings of 60, 70, 80, 90.

Process and measure OD at center

[AEC Consistency Testing-kVp]

AEC should adjust time to maintain OD with different kVp settings.

+/- 15 %
+/- 0.3 OD

Center tube to bucky and phantom at 40” SID

Place 10 X 12 in bucky and expose, repeat four times, using 100 mA station and kVp settings of 60, 70, 80, 90.

Process and measure OD at center

11

[AEC Consistency Testing-Part Thickness]

AEC should adjust [_____] to maintain OD with different part thicknesses.

+/- [__] %
+/- [__] OD

Center tube to bucky + phantom at 40” SID

Place 10 X 12 in bucky and expose three times with an 100 mA station, adding a layer of material so images are taken with 10, 20 + 30cm of acrylic.

Process and measure OD at center

[AEC Consistency Testing-Part Thickness]

AEC should adjust time to maintain OD with different part thicknesses.

+/- 10 %
+/- 0.2 OD

Center tube to bucky + phantom at 40” SID

Place 10 X 12 in bucky and expose three times with an 100 mA station, adding a layer of material so images are taken with 10, 20 + 30cm of acrylic.

Process and measure OD at center

12

[AEC Consistency Testing-Field Size]

AEC should adjust [_____] to maintain OD with different areas of collimation

+/- [__] %
+/- [__] OD

Center tube to bucky and phantom at 40” SID

Place a film in bucky taking three exposures at 100 mA an collimation of 6 X 6, 10 X 10 and 14 X 14

Process and measure OD at center

[AEC Consistency Testing-Field Size]

AEC should adjust time to maintain OD with different areas of collimation

+/- 5 %
+/- 0.1 OD

Center tube to bucky and phantom at 40” SID

Place a film in bucky taking three exposures at 100 mA an collimation of 6 X 6, 10 X 10 and 14 X 14

Process and measure OD at center

13

[AEC Consistency Testing-Detector]

AEC should adjust [_____] to maintain OD with different detector configurations

+/- [__] %
+/- [__] OD

Center tube to bucky and phantom at 40” SID, 100mA and 70 kVp

Place 14 X 17 in bucky and expose three times using each detector

Process and measure OD at center

[AEC Consistency Testing-Detector]

AEC should adjust time to maintain OD with different detector configurations

+/- 10 %
+/- 0.2 OD

Center tube to bucky and phantom at 40” SID, 100mA and 70 kVp

Place 14 X 17 in bucky and expose three times using each detector

Process and measure OD at center

14

[AEC Reproducibility]

AEC should maintain OD when the same [_____] and [_____] are used

+/- [__] %
+/- [__] OD

Center tube to bucky and phantom at 40” SID

Place 10 X 12 in bucky and expose three times, using80 kVp at 200mA.

Process and measure OD at center

May also be done with a meter (mR), +/- 0.05 variance

[AEC Reproducibility]

AEC should maintain OD when the same mA and kVp are used

+/- 5 %
+/- 0.1 OD

Center tube to bucky and phantom at 40” SID

Place 10 X 12 in bucky and expose three times, using80 kVp at 200mA.

Process and measure OD at center

May also be done with a meter (mR), +/- 0.05 variance

15

[Back up Timer]

Back up or maximum exposure limits should be set at [__] mAs or [__] seconds

This will prevent over exposure to patients and damage to the tube.

[Back up Timer]

Back up or maximum exposure limits should be set at 600mAs or 6 seconds

This will prevent over exposure to patients and damage to the tube.

16

[Tomography]

Types:
[_____], [_____], [_____], [_____] and [_____].

Tomography works to [_____] objects above + below the area of interest or object plane.

The object plane’s center is the [_____] and is measured from [_____] up.

The greater the tube movement / the more complex the movement, the [_____] the object plane.

[Tomography]

Types:
Linear, circular, elliptical, hypocycloidal and trispiral.

Tomography works to blur objects above + below the area of interest or object plane.

The object plane’s center is the fulcrum and is measured from table top up.

The greater the tube movement / the more complex the movement, the smaller the object plane.

17

[Tomography- Section Level]

Assures that the selected [_____] level is accurate. +/- [__]

Evaluation is made with a test tool. Acrylic with numbers imbedded in it at their respective level, for example 4 is at 4cm.

The number that is most clearly visualized is the fulcrum height.

[Tomography- Section Level]

Assures that the selected fulcrum level is accurate. +/- 5mm

Evaluation is made with a test tool. Acrylic with numbers imbedded in it at their respective level, for example 4 is at 4cm.

The number that is most clearly visualized is the fulcrum height.

18

[Tomography- Incrimination Level]

Assures that [_____] is accurate

+/- [__]

Repeat section level test for appropriate height.

If test passes for 4cm, change to 6cm and this should be the number in focus.

[Tomography- Incrimination Level]

Assures that measuring device is accurate

+/- 2mm

Repeat section level test for appropriate height.

If test passes for 4cm, change to 6cm and this should be the number in focus.

19

[Tomography]

Exposure angle:
30° and greater = +/- [__] °
30° and less = +/- [__] °

Spatial resolution:
Using a test tool, wire mess, a minimum of [__] holes per inch should be visible. This will determine the level of detail in an image.

[Tomography]

Exposure angle:
30° and greater = +/- 5°
30° and less = +/- 2°

Spatial resolution:
Using a test tool, wire mess, a minimum of 40 holes per inch should be visible. This will determine the level of detail in an image.

20

[Tomography- Section Uniformity and Beam Path]

Section uniformity- exposure is taken and resulting patter, line for linear, is measured with densitometer. Measurements should be consistent, +/- [__] OD

Beam Path- using the same tool, evaluate the beam path or geometry. Pluridirectional tubes should be +/- [__] of path length.

[Tomography- Section Uniformity and Beam Path]

Section uniformity- exposure is taken and resulting patter, line for linear, is measured with densitometer. Measurements should be consistent, +/- 0.3 OD

Beam Path- using the same tool, evaluate the beam path or geometry. Pluridirectional tubes should be +/- 10% of path length.

21

[Grid Uniformity]

Problems can occur at time of manufacture or if grid is [_____].

Take an exposure of an acrylic phantom with the grid in place.

Select a technique that will give an OD of 1.5.

Take OD readings of center and 4 quadrants, all values should be +/- [__] %

[Grid Uniformity]

Problems can occur at time of manufacture or if grid is dropped.

Take an exposure of an acrylic phantom with the grid in place.

Select a technique that will give an OD of 1.5.

Take OD readings of center and 4 quadrants, all values should be +/- 10 %

22

[Grid Alignment/Latitude]

Proper centering and SID for focused grids. Alignment becomes more critical with [_____] grid ratios.

Latitude describes margin of error before significant [_____] takes place.

Each variable is set by the [_____].

Grid test tools are [_____] available.

[Grid Alignment/Latitude]

Proper centering and SID for focused grids. Alignment becomes more critical with rising grid ratios.

Latitude describes margin of error before significant cutoff takes place.

Each variable is set by the manufacturer.

Grid test tools are commercially available.