Post on 29-Mar-2015
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Lecture No.2X Ray films
Dr. Mustafa Zuhair MahmoudMr. Ali Alhailiy
Image Critiqueاالشّع�ه صورة نقد
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X-ray Film
1. Film Construction:
• X-ray film is constructed of four layers basically which are:
1. Base.2. Adhesive layer.3. Emulsion.4. Overcoat (protective) layer.
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
1. Film Construction:
• X-ray film is constructed of four layers basically which are:
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
1. Film Construction:
• X-ray film is constructed of four layers basically which are:
1. Base: 150 to 300 m thick. Lucent. Made of polyester. Blue in color result in less eye strain and fatigue.
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
1. Film Construction:
• X-ray film is constructed of four layers basically which are:
2. Emulsion: This is the active layer. Homogeneous mixture of gelatin and silver halide crystals. The gelatin acts as a suspension agent and prevents the crystals from
adhering to one another. And allow the light to pass throw when viewing the image.
Two emulsion layers on each side of the film base (1/2000 in thickness).
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
1. Film Construction:
• X-ray film is constructed of four layers basically which are:
3. Adhesive layer: Very thin layer of solution of cellulose ester and gelatin in water and acetone,
put on the base. Function of adhesive (substratum) layer to adhere the layers of emulsion to
the base.
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
1. Film Construction:
• X-ray film is constructed of four layers basically which are:
4. Overcoat (protective) layer: The purpose of the overcoat of an x-ray film is to protect the emulsion layer.
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
2. Film Types (Clinical Usage):
A. Direct Exposure Film:
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
2. Film Types (Clinical Usage):
A. Direct Exposure Film:
Used without intensifying screens.
Used mainly for extremities, previously for mammography.
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
2. Film Types (Clinical Usage):
A. Direct Exposure Film:
Requires 10 – 100 times more the exposure dose.
The emulsion is thicker than screen film.
Renders excellent detail.
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
2. Film Types (Clinical Usage):
B. Mammographic Film:
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
2. Film Types (Clinical Usage):
B. Mammographic Film:
Single emulsion.
Fine grain (crystal shape).
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
2. Film Types (Clinical Usage):
C. Video Film:
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
2. Film Types (Clinical Usage):
C. Video Film:
Exposes images displayed on a video monitor.
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
2. Film Type (Clinical Usage):
D. Laser Film:
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
2. Film Type (Clinical Usage):
D. Laser Film:
Uses a laser printer.
Provides excellent image quality.
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
2. Film Type (Clinical Usage):
D. Laser Film:
Sensitive to red light.
Must be processed in complete darkness.
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
2. Film Type (Clinical Usage):
E. Duplication film:
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
2. Film Type (Clinical Usage):
E. Duplication film:
Single emulsion film.
Used for producing copies of radiographs.
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
2. Film Type (Clinical Usage):
F. Subtraction Film:
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
2. Film Type (Clinical Usage):
F. Subtraction Film:
A type of single emulsion film used with angiography.
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
2. Film Type (Clinical Usage):
F. Subtraction Film:
One type prepares a positive copy of the image.
The other type enhances subject contrast and detail.
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
2. Film Type (Clinical Usage):
G. Cine Film:
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
2. Film Type (Clinical Usage):
G. Cine Film:
Used with cardiac catheterization.
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
2. Film Type (Clinical Usage):
G. Cine Film:
Produced in 16 and 35mm sizes.
Also used for radiography of the esophagus.
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
2. Film Type (Clinical Usage):
H. Spot Film:
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
2. Film Type (Clinical Usage):
H. Spot Film
Produced in 70 and 105mm sizes.
Used in fluoroscopy with a spot film camera.
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
2. Film Type (Clinical Usage):
I. Dental Film
Periapical Dental Film
Bite-wing Dental FilmAssistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
2. Film Type (Clinical Usage):
I. Dental Film
Occlusal Dental Film Orthopantomographic (OPG) Dental Film
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
2. Film Type (Clinical Usage):
I. Dental Film
Exposed either intraorally or extraorally.
Intraoral films are small, double-emulsion films.
Extraoral films are large, single-emulsion films.
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
3. Film Type (Exposure):
A. Screen Film:
Films exposed to combination of X-ray and light (screen film).
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
3. Film Type (Exposure):
B. Non Screen Film:
Films exposed to x-ray only (non screen film).
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
3. Film Type (Exposure):
C. Fluoroscopy and Copying Films:
These Films are exposed to light only.
Coated by the emulsion in one side and called single sided films.
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
5. Film Handling and Storage:
Each of the following can have a negative effect upon film contrast.
1. Improper handling. Causes artifacts.
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
5. Film Handling and Storage:
Each of the following can have a negative effect upon film contrast.
2. Heat and humidity. Too much humidity can cause the emulsion to swell.
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
5. Film Handling and Storage:
Each of the following can have a negative effect upon film contrast.
2. Heat and humidity. Too little humidity can cause static to develop the film.
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
5. Film Handling and Storage:
Each of the following can have a negative effect upon film contrast.
2. Heat and humidity. Too much heat can fog film.
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
5. Film Handling and Storage:
Each of the following can have a negative effect upon film contrast.
3. Light and radiation. Exposure to each can fog film decreasing contrast.
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
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X-ray Film
5. Film Handling and Storage:
Each of the following can have a negative effect upon film contrast.
4. Shelf life. Film loses speed, contrast and begins to fog with age.
Assistant Prof. Dr. Mustafa Zuhair Mahmoud
CR Cassettes Comprises of:
• 1. A protective outer cassette case
• 2. A PSP plate
• 3. A chip for temporary storage of patient information
Photo-Stimulable Phosphor (PSP)
• A phosphor is a substance that exhibits the• phenomenon of phosphorescence (sustained• glowing after exposure to light or energised• particles such as electrons).• • The most common types of phosphor in
these• plates are BaF:Eu++. (Barium Fluoro
Europium)
CR Plate Structure
Protective Coat
Electron beam cured to reduce the amount oflaser beam reflection that occurs during secondary excitation.
Phosphor Layer
The thickness of this layer has a direct impacton image quality.PSP is made either of BaF:Eu++ or BaFI:Eu++
Anti-Halo Layer
This layer is to prevent back-reflection of the of the laser light into the phosphor.It is normally a blueish colour. Can you think why?Absorption, because the laser is normally red.
Support Layer
This polyurethane (PET) layer gives strengthand support to the plate.
Laminate
This layer provides further support.
CR Cassettes
• Hard outer cassettes provide durability and functionality.
• These are commonly made either of plastic or carbon fibre,both of which have good radio-lucency in proportion to theirsupport qualities and durability.
Communication• Patient ID is normally• inputted on a PC• workstation and transferred• or wrote to an embedded• chip within the cassette by• magnetics or radio-waves• • This information is then read• by the reader during the• reading process.
Communication• Barcode scanners arecommonly used toautomatically identifycassettes.
• This speeds up theadministration process.
Readers
The Reading Process
• 1. Primary excitation• 2. Secondary excitation• 3. Photomultiplication• 4. Digitisation• 5. Plate erasing
Excitation
Excitation is theelevation of the energylevels of a substancefrom its normal or“ground” state• There are two levels of excitation in CR plates:– Primary– Secondary
Primary Excitation
The x-rays pass through the upper layer to the phosphor.• The x-rays react with these molecules, causing inner shell electrons to become outer shell electrons.• Most of these drop back to their initial state (70%)• The rest (30%) get trapped in electron traps• These traps are caused by the addition of impurities into the Barium Fluoro Halide (i.e., Europium)• This is effectively stores the imagewithin the plate (the latent image)
Secondary Excitation
• The plate is removed from the cassette and passes by a laser
• beam. This beam reacts with the trapped electrons
Secondary ExcitationThe laser stimulates the phosphor plate enoughto release the trapped electrons to their orignalstate. This causes light to be emitted.• The light produced is channeled to aphotomultiplier using optics (lenses and mirrors)• The number of light photons produced bysecondary excitation is directly proportional tothe number of electrons that were trapped in thestorage phosphor.
A red laser is used for secondary excitation, but green light is emitted.There is then a filter for omitting non-green light (i.e., specular reflections from theprimary laser)
The Photomultiplier
Extremely sensitive detectors.These amplify or multiply light signals intosignals up to 100,000,000 times
Digitisation
A/DConvertorPMT
Plate Erasing
. A white light source, typically a fluorescent lamp with an attached colour filter, quickly erases the image plate.• Now the plate can be reused.
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