Recorded Detail/Spatial Resolution

Question 1

What are other terms used for recorded detail?

Answer 1

Sharpness, detail, definition

Question 2

Recorded Detail

The ability of a system to ___ record the ___ ___ of the object you are imaging.

Are the structural lines ___ or ___?

Answer 2

Recorded Detail

The ability of a system to accurately record the structural lines of the object you are imaging.

Are the structural lines sharp or blurry?

Question 3

Spatial Resolution

• Ability of an imaging system to accurately display objects in ___ ___.
• With the digital image shown on a ___ this has slightly changed the ___.
• The Digital Imaging courses will go into further information for the digital images.

Answer 3

Spatial Resolution

• Ability of an imaging system to accurately display objects in two dimensions.
• With the digital image shown on a monitor this has slightly changed the definition.
• The Digital Imaging courses will go into further information for the digital images.

Question 4

Assessing Recorded Detail

• ___ of ___
• ___ ___ Test measured in ___ per ___ (lp/mm)
• ___ ___ Test

Answer 4

Assessing Recorded Detail

• Unit of resolution
• Line Pairs Test Measured in lines per millimeter (lp/mm)
• Star Pattern Test

Question 5

What 3 categories affect recorded detail?

Answer 5

1. Motion
2. Material(s)
3. Geometric

Question 6

Motion

Motion unsharpness is the most detrimental factor contributing to a lack of ___ ___ or ___.

Answer 6

Motion

Motion unsharpness is the most detrimental factor contributing to a lack of image definition or sharpness.

Question 7

Effects on Image Appearance

Images lacking fine detail appear ___

Assessment of motion

Answer 7

Effects on Image Appearance

Images lacking fine detail appear blurry

Assessment of motion

Question 8

What are the 3 types of motion?

Answer 8

1. Voluntary motion
2. Involuntary motion
3. Equiptment motion

Question 9

What can help with involuntary motion?

Answer 9

• Exposure time reduction
• Immobilization

Question 10

You must control motion

• Explain the exam to the patient. Must take in the patient’s ___ into consideration
• How do you talk to an ___ patient vs a ___?

Use ___ devices if necessary. ___, ___, ___ ___.

Answer 10

You must control motion

• Explain the exam to the patient. Must take in the patient’s age into consideration
• How do you talk to an elderly patient vs a child?

Use immobilization devices if necessary. Tape, sandbags, lead aprons.

Question 11

Motion

• ____ exposure time needed
• 100 MA at .10
• 200 MA at .05
• 400 MA at .025

Which would be the best to use: All factors = 10 mAs

Answer 11

Motion

Reduce exposure time needed

• 100 MA at .10
• 200 MA at .05

• 400 MA at .025

Which would be the best to use: All factors = 10 mAs

Question 12

Motion

use a ___ speed film/screen combination if needed

Look at the ___/____ relationship if needed.
▲KVP by ___% - cut mAs in ___

• ex. 20 MAS at 60 KVP
• 400 mA at .05 sec. at 60 KVP
• 400 mA at 0.025 sec. at 69 KVP

Answer 12

Motion

use a higher speed film/screen combination if needed

Look at the KVP/mAs relationship if needed.
▲KVP by 15% - cut mAs in half

• ex. 20 MAS at 60 KVP
• 400 mA at .05 sec. at 60 KVP
• 400 mA at 0.025 sec. at 69 KVP

Question 13

What are 3 things that can contribute to material unsharpness?

Answer 13

Type of film, intensifying screens, film/screen contact

Question 14

Type of Film

___ speed = ___ detail (___ crystals and ___ emulsion)

___ speed = ___ detail (___ crystals and ___ emulsion)

Answer 14

Type of Film

Slow speed = more detail (smaller crystals and thinner emulsion)

Fast speed = less detail (larger crystals and thick emulsion)

Question 15

Type/Speed of Intensifying Screens

non-screen or cardboard – ___ detail because ___ light is given off during the exposure.

Slow Screen speed = ___ detail - ___ crystals – ___ light is given off during the exposure.

___ layer - ___ detail because ___ light is given off during the exposure.

Answer 15

Type/Speed of Intensifying Screens

non-screen or cardboard – better detail because no light is given off during the exposure.

Slow Screen speed = Better detail - smaller crystals – less light is given off during the exposure.

Thinner layer - Better detail because less light is given off during the exposure.

Question 16

Fast Screen Speed

Fast Screen speed = ___ detail (___ light is given off during the exposure)

• ___ crystals – ___ light is given off during the exposure
• Thick layer – ___ light

Answer 16

Fast Screen Speed

Fast Screen speed = decrease detail (more light is given off during the exposure)

• larger crystals – more light is given off during the exposure
• Thick layer – more light

Question 17

Radiographic Noise

is an undesirable ___ in the ___ ___ of the image. You can have “noise” on a radiographic film, TV monitor, digital images or CT monitor.

Compare - audio and video noise as “snow”.

Answer 17

Radiographic Noise

is an undesirable fluctuation in the optical density of the image. You can have “noise” on a radiographic film, TV monitor, digital images or CT monitor.

Compare - audio and video noise as “snow”.

Question 18

What are the 3 terms to describe radiographic noise?

Answer 18

Film graininess, structural mottle, and quantum mottle

Question 19

Radiographic Noise

1. Film graininess-refers to the distribution in ___ and ___ of the ___ ___ crystals in the ___ layer.
2. Structural Mottle similar to film graininess, but it refers to the construction of the ___ layer of the ___ screens. (Both are ___ in the film/screen combinations and the radiographers has ___ control over these factors)
3. Quantum Mottle - refers to the ___ nature in which x-rays interact with the ___.

Answer 19

Radiographic Noise

1. Film graininess-refers to the distribution in size and space of the silver halide crystals in the emulsion layer.
2. Structural Mottle similar to film graininess, but it refers to the construction of the phosphor layer of the intensifying screens. (Both are inherent in the film/screen combinations and the radiographers has no control over these factors)
3. Quantum Mottle - refers to the random nature in which x-rays interact with the IR.

Question 20

Digital – if your technique is set too ___ (___) for the particular body part = ___ image

Digital Images = Poor ___ to ___ Ratio refers to ___ IR radiation exposure (___ image).

Answer 20

Digital – if your technique is set too low (underexposed) for the particular body part = grainy image

Digital Images = Poor Signal to Noise Ratio refers to low IR radiation exposure (underexposed image).

Question 21

As a General Rule:

fast image receptor have ___ radiographic noise and ___ resolution.

___ resolution requires ___ noise and ___ image receptors.

Digital Systems: signal to noise ratio: *___ signal – ___ noise

Answer 21

As a General Rule:

fast image receptor have high radiographic noise and low resolution.

high resolution requires low noise and slow image receptors.

Digital Systems: signal to noise ratio: *high signal – low noise

Question 22

Film Screen Contact

___ ___ test

Answer 22

Film Screen Contact

Wire Mesh test

Question 23

What are the 3 geometric factors?

Answer 23

1. FSS
2. OID
3. SID

Question 24

Distances

Answer 24

Distances

Question 25

_Focal Spot Size_ \_\_\_ the FSS – the ___ the sharpness of detail

Answer 25

_Focal Spot Size_ **Smaller** the FSS – the **better** the sharpness of detail

Question 26

_OID_ You want the object of interest as ___ to the image receptor as possible (the closer, the \_\_\_). As the OID increases, you will ___ the detail. (\_\_\_)

Answer 26

_OID_ You want the object of interest as **close** to the image receptor as possible (the closer, the **sharper**). As the OID increases, you will **decrease** the detail. (**Magnification**)

Question 27

_SID_ Teleoroentgenography – 72” SID will be using the ___ portion of the primary beam. “\_\_\_ to size”

Answer 27

_SID_ Teleoroentgenography – 72” SID will be using the **parallel** portion of the primary beam. “**True** to size”

Question 28

What are 2 terms to describe area of unsharpness?

Answer 28

1. Penumbra 2. Umbra

Question 29

_Penumbra and Umbra_ Penumbra is the area of ___ around the recorded ___ of the object. Umbra is the area of ___ around the recorded ___ of the object.

Answer 29

_Penumbra and Umbra_ Penumbra is the area of **unsharpness** around the recorded **edges** of the object. Umbra is the area of **sharpness** around the recorded **edges** of the object.

Question 30

Answer 30

Question 31

_Assessing Recorded Detail_ kVp and mAs doesn't control ___ \_\_\_

Answer 31

_Assessing Recorded Detail_ kVp and mAs doesn't control **structural lines**

Question 32

Using the 3 geometric factors – what combination would give you the BEST detail?

Answer 32

* Small FSS * Short OID * Long SID

Question 33

What is the formula for penumbra?

Answer 33

Penumbra = effective FSS x OID/SOD | (SID-OID= SOD)

Question 34

_Digital Image Receptor Systems_ Image processing system ___ recorded detail Spatial resolution is dependent on: * ___ and ___ \_\_\_ * ___ \_\_\_ * ___ \_\_\_ ___ \_\_\_

Answer 34

_Digital Image Receptor Systems_ Image processing system **limits** recorded detail Spatial resolution is dependent on: * **Acquisition** and **display matrix** * **Pixel size** * **Gray scale bit depth**

Question 35

_Spatial Resolution_

Answer 35

_​Spatial Resolution_

Question 36

_Spatial Frequency_ \_\_\_ frequency signal (better) Determined by measuring ___ between ___ of ___ distinct from one another

Answer 36

_Spatial Frequency_ **High** frequency signal (better) Determined by measuring **distance** between **pairs** of **lines** distinct from one another

Question 37

_Noise_ \_\_\_ information received by ___ \_\_\_ Quantum noise is also called ___ \_\_\_ \_\_\_ signal and ___ noise = good image

Answer 37

_Noise_ **Background** information received by **image receptor** Quantum noise is also called **quantum mottle** **High** signal and **low** noise = good image