Image Modalities Exam 3 Review

Outer cells

When utilizing AEC, chest x-rays should utilize these cells to prevent over exposure of lung fields

150%

An AEC backup timer is set at this in regard to its expected mA

Time

AEC only controls this

600

Automatic termination of an exposure is required by law to occur at this mAs when more than 50 kVp is utilized

Overexposure

When an activated AEC chamber is collimated off this results

3

How many chambers do AEC chambers typically have?

Aluminum Filters

This is used to measure half value layers

Plus or minus 2%

An SID error of this is allowed with testing collimator accuracy

Repeat image analysis

This quality control measure should be performed on a continual basis

Quality control and quality assurance

These are the two types of quality management

Focal spot size estimation

The pinhole camera, star test pattern, and line pair resolution test tool are all tools used to perform quality control for this

Plus or minus 5%

This is the deviation allowed for exposure timer settings

Additive

Pneumonia is considered this type of pathology

Density setting

This setting regulates the density of an image and should not be used to compensate for part thickness

Anatomically programmed radiography (APR)

This is a feature found on modern digital x-ray systems that stores pre-set exposure techniques for specific examinations and patient sizes

Approximately 10 kVp

In a clinical setting, a 15% change in kVp is equal to this

Proportional anatomy groupings

This is the method of determining exposure techniques for one body part based on a known technique for another body part with similar thickness and tissue composition

mAs

When using a variable kVp technique chart, this remains nearly fixed

Focal plane

All recorded detail in objects outside of this will appear blurred

Time required to travel tomographic amplitude

Exposure time has to match this

Amplitude

The total distance traveled by the tube is known as this

Before exposure

To avoid motion artifacts in tomography, this is when tube motion should occur

Sharp

The anatomy located at the fulcrum of a tomographic image appears like this

10

In digital tomosynthesis, the image database is created from approximately this many exposures at different angles

Exposure angle, Inversely proportional

Section thickness is controlled by this and has this relationship to it

Destructive

Degenerative arthritis, emphysema, and pneumothorax are examples of this type of pathology

Increase

When going from no grid, to utilizing a grid, this is how exposure factors should be adjusted

Phantom image

Tube motion parallel to the long axis of a structure results in this

Directly above appropriate chamber

Anatomy should be positioned like this in regards to the ionization chamber(s) when utilizing AEC

2.5

For a half value layer test, the following exposures are measured by an ion chamber with increasing amounts of aluminum absorber placed in the beam as indicated below.

This is the HVL for this x-ray beam

0 mm Al: 200 mR

1 mm Al: 160 mR

2 mm Al: 120 mR

3 mm Al: 80 mR

Fulcrum

What determines focal plane location?

Exposure angle

What controls section thickness?

Thinner section

Larger tomographic angle results in what?

Parallel tube motion and blur overlap

What causes phantom images?

Exposure time

Which exposure factor does AEC directly control?

Outer cells

Which AEC cells are commonly used for chest radiography?

Additive pathology

What pathology requires increased exposure factors?

Destructive pathology

What pathology requires decreased exposure factors?

Ionization chamber

What is the most common modern AEC detector

Linear motion

What tomographic movement remains most common today?

QA and QC

What are the two components of quality management?

QA

Which focuses on people and processes?

QC

Which focuses on equipment?

Filtration required to reduce beam intensity by half

What does HVL measure?

DQE

What is the primary QA parameter for digital detectors?

+/- 5%

What is the acceptable kVp accuracy?

+/- 5%

What is the acceptable exposure reproducibility?

MQSA

Which law mandates FDA approval of mammography services?

The Joint Commission (TJC)

What organization is the largest accreditor?

1. Establish criteria

2. Monitor performance

3. Collect data

4. Analyze data

5. Evaluate data

What are the five steps of QA monitoring?