Radiography Basics Quiz

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Questions and Answers

Which of the following is NOT a method of film labeling?

Chemical processing (correct)

Lead markers

Lead-impregnated tape

Photo-imprinting

What advantage does digital radiography offer over traditional film?

Images can be permanently altered and stored on film.

It requires chemical processing for image development.

Images must be retrieved from a single location.

Immediate acquisition and easy modification of images. (correct)

Which aspect of digital technology improves communication with referring physicians?

Images are stored in isolated locations.

Report generation takes several days.

Hard copies of images are always required.

Physicians can view images on desktop computers immediately. (correct)

What is one of the steps in obtaining digital images according to the general principle?

Conversion of x-ray energy into electrical charges. Signup and view all the answers

What happens to the dose required as the speed of an imaging system increases?

It decreases. Signup and view all the answers

Which characteristic is associated with the quality of an imaging system's resolution?

Inversely proportional to speed. Signup and view all the answers

What should be avoided when unloading film from a cassette?

Digging the film out with fingernails. Signup and view all the answers

What is a recommended material for cleaning radiographic screens?

Manufacturer-recommended preparation with antistatic compound. Signup and view all the answers

What is the typical storage duration for obstetrical ultrasound records?

25 years Signup and view all the answers

Which component of the film-screen technology is responsible for converting x-ray energy to visible light?

Phosphor layer Signup and view all the answers

Which of the following is NOT a basic step in film processing?

Dry cleaning. Signup and view all the answers

What is the purpose of a dark room in film processing?

To process the film without exposure to light. Signup and view all the answers

What is the main purpose of using an intensifying screen in radiography?

To decrease patient exposure to x-rays Signup and view all the answers

Which of the following materials is NOT commonly used in the phosphor layer for intensifying screens?

Magnesium Oxide Signup and view all the answers

Why is it important to label radiographs?

For easy identification. Signup and view all the answers

What characteristic is NOT true for the base layer in film-screen technology?

Is radiopaque to x-rays Signup and view all the answers

What is one characteristic of a well-maintained dark room?

It should be organized with separate wet and dry areas. Signup and view all the answers

What type of luminescence occurs spontaneously with an immediate light emission following excitation?

Fluorescence Signup and view all the answers

How are pediatric radiographs stored until a patient reaches adulthood?

Until the patient’s 25th birthday Signup and view all the answers

Which of the following describes a feature of a reflective layer in film-screen technology?

Redirects light towards the film Signup and view all the answers

What is the primary function of the film-screen receptor in imaging technology?

To convert the latent image into a visible image Signup and view all the answers

Which of the following is NOT a component of film-screen technology?

Fluorescent screen Signup and view all the answers

What materials are typically used for the front cover of an X-ray cassette?

Aluminum and carbon fiber Signup and view all the answers

What is the purpose of the back cover in an X-ray cassette?

To prevent backscatter radiation Signup and view all the answers

Which layer is part of the X-ray film structure?

Protective Coating Signup and view all the answers

What is the primary characteristic of the film base used in X-ray films?

It is a lightweight material Signup and view all the answers

What is a significant disadvantage of film-screen technology?

It can be affected by environmental factors Signup and view all the answers

Which of the following statements best describes digital imaging?

Images can be easily manipulated and displayed on monitors. Signup and view all the answers

What is the purpose of the adhesive layer in film manufacturing?

To glue the emulsion to the base and prevent bubbles Signup and view all the answers

Which property is NOT desirable for film bases in preventing crossover?

Translucent Signup and view all the answers

What is the maximum allowable optical density from the base material and film fog?

0.30 OD Signup and view all the answers

Which of the following is an appropriate storage condition for unexposed X-ray film?

Temperature between 18⁰ C to 23⁰ C Signup and view all the answers

What happens to the silver halide crystals in the film upon exposure to light?

They form the latent image on the film Signup and view all the answers

How should loaded cassettes with X-ray film be stored to prevent damage?

Stored vertically in a shielded area Signup and view all the answers

What is the recommended humidity level for storing unexposed X-ray film?

Between 40% and 60% Signup and view all the answers

What is the maximum limit of radiation exposure that should be allowed for film storage?

0.1 mGy Signup and view all the answers

What is the primary component used in computed radiography for recording images?

Photostimulable storage imaging plate Signup and view all the answers

Which of the following best describes the process utilized in computed radiography after imaging?

The imaging plate is first read by a CR reader. Signup and view all the answers

Which layer of the imaging plate is essential for holding the photostimulable phosphor?

Base layer Signup and view all the answers

What type of detectors does digital radiography utilize?

Direct and indirect detectors Signup and view all the answers

What is one disadvantage of digital radiography compared to analog methods?

The initial setup cost is expensive. Signup and view all the answers

Which material is specifically used for direct digital radiographic detectors?

Amorphous silicon Signup and view all the answers

How does digital radiography ensure minimal radiation exposure?

By employing advanced imaging technologies. Signup and view all the answers

Which factor is crucial for increasing the sharpness of images in computed radiography?

Light absorption by the layers Signup and view all the answers

Study Notes

Course Information

Course title: Introduction to Medical Imaging
Course code: HSMI 1211
Department: Diagnostic Imaging and Radiotherapy
Kulliyyah: Allied Health Sciences

Learning Outcomes

Students will be able to list various image recording technologies.
Students will be able to discuss film-screen technology (principles, advantages, limitations).
Students will be able to discuss digital technology (principles, types, advantages, limitations).

Image Recording Methods

Analog: Radiographic images are permanently recorded on film.
Digital: Radiographic images are displayed on a monitor and can be manipulated. Methods for recording include film-screen technology, imaging plates, and flat panel detectors.

Analog Method: Film-Screen Technology

Film-screen receptor: The component that receives the latent x-ray image and converts it to a visible image.
Components: Cassette, film, intensifying screen.
Cassette function: Acts as a protector to film, lightproof, prevents bending/scratching, ensures film and intensifying screen are in close contact.
Cassette consistency: Front cover (radiolucent material like aluminum, carbon fiber, light weight), and back cover (heavier metal like lead foil to prevent/absorb backscatter radiation).
Film consistency: Film base, film emulsion, protective coating; cellulose nitrate or triacetate base; flexible yet tough, stable, and rigid; uniformly lucent.
Film emulsion: Composed of silver halide crystals suspended in gelatin; sensitive to radiation; forms latent image on film.

Film-screen Technology: Intensifying Screen

Purpose: X-ray film is more sensitive to light than x-rays; converts x-ray energy to visible light (amplifies x-ray beam); converts each x-ray into many light photons; decrease x-ray dose to the patient; decrease motion blur or unsharpness.
Characteristics: Phosphor crystal layer with protective coating; high level of x-ray absorption; high x-ray-to-light conversion; little or no "afterglow" following radiation.
Base layer: Polyester is the preferred material because it is flexible, yet tough, rigid, chemically inert, and uniformly radiolucent. Magnesium oxide or titanium dioxide may be added to redirect light towards the film, and an absorptive layer (coloured dye) may absorb light moving away from the film.
Phosphor layer: Active layer of intensifying screen; emits light (fluorescence) when stimulated by x-rays; calcium tungstate (CaWO4); rare earth elements (gadolinium, lanthanum, yttrium) are used in newer, faster screens.
Luminescence: Certain materials emit light in response to excitation. Two types: fluorescence (instantaneous emission of light after excitation), and phosphorescence (delayed emission of light).

Film-screen Technology: Screen/Film Combination

Design: Designed to complement each other to provide a quality image; intensifying screens to emit light at a specific wavelength; films with enhanced sensitivity to that wavelength.
Speed: Speed of imaging system is inversely proportional to the dose; as speed increases, dose required decreases to obtain the desired optical density.
Resolution: Recorded detail or sharpness. Ability of an imaging system to demonstrate detail varies depending on the purpose.
Care of screens: Handle carefully to prevent scratches, place film inside cassette, don't dig out with fingernails, and keep cassette closed. Clean regularly using manufacturer-recommended preparations (often antistatic). Ensure screens are completely dry before reloading.

Film-screen Technology: General Principle

X-ray beam strikes cassette and screens.
Light produced in the screen corresponds to the beam intensity.
Light acts on the film (latent image); processed to highlight the image.
Modulated beam interacts with compounds in radiographic film to produce the latent image.
An invisible image is formed on the film, later made visible by photographic development.
The image needs to be processed to be visible.

Film-screen Technology: Film Processing

Film processing methods: Manual (films put into different chemicals by radiographer), film processor (uses tanks with different chemicals).
Steps in film processing:
- Developing, rinsing (stop bath), fixing, washing, drying
Chemical processing: X-ray exposure → invisible latent image → developer → fixer → wash → dry → visible image.
Darkroom characteristics: Clean, Organized (dry & wet areas), Lightproof, Safelight.

Film-screen Technology: Film Identification

Every radiograph should be labelled properly for easy identification.
Information on film should be permanent (name/address of hospital, date, patient ID, methods of labelling (lead markers, lead-impregnated tape, photo-imprinting).

Film-screen Technology: Film Filing

Radiographic film should be completely dry, labelled appropriately, placed in a film sleeve, and filed according to the hospital filing system for easy location.

Film-screen Technology: Limitations

Chemical hazard.
Image cannot be altered/manipulated/erased.
Poor image results may require repetition/retake, increase radiation dose, and increase patient waiting times, leading to cost increase.
Film used for one projection cannot be reused, and stored for a specific period.
Retrieval of radiographic images can be time-consuming.

Digital Method: Computed Radiography (CR)

Digital radiographic system uses a photostimulable storage imaging plate (PSP or IP).
Introduced in the 1980s by Fuji.
A CR reader processes the plate, creating an image; a two-step process.
IP is a rigid sheet with several layers, designed to record and enhance image transmission. A protective layer, phosphor layer, conductor layer, support layer, light shielding layer, and backing layer. Protective layers insulate the IP from handling damage.
The phosphor layer holds the phosphor active component of the IP.
The support layer grounds the plate to eliminate electrostatic problems.
The backing layer absorbs lights to increase sharpness.

Digital Method: Digital Radiography (DR)

Digital detectors absorb x-ray energy.
Converts x-ray energy to electrical charges; computer processes these signals using post-processing software.
Results displayed on monitors before possible hard copy creation.
Two types of detectors: direct (x-ray to electronic signal); indirect (x-ray → light → electronic signal).

Digital Method: Advantages & Disadvantages

Advantages: Less radiation dose, archiving in less space, images can be viewed in softcopy/hardcopy, images can be manipulated, images can be transmitted, reusable detectors, no chemicals needed for processing, faster retrieval, less possibility of image loss.
Disadvantages: Expensive to set up, overexposure of radiation may not be easily detected.

Digital Technology: Digital Images

Images are viewed via softcopy monitors or via hardcopy (printed film).

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Description

Test your knowledge on the essential concepts of radiographic film, digital radiography, and imaging systems. This quiz covers topics such as film processing, resolution, and the advantages of digital technology in medical imaging. Challenge yourself and see how well you understand these critical aspects of radiography.