Introduction to Fluoroscopy and Angiography

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Questions and Answers

What is the function of the input phosphor in an image intensifier?

To emit electrons upon stimulation

To focus the emitted electrons

To convert x-ray energy into visible light (correct)

To reverse the image for output

Which material is used for the output phosphor in the imaging process?

Zinc Cadmium Sulfide (correct)

Copper Sulfate

Cesium Iodide

Antimony Compounds

What is the process called when electrons are emitted from the photocathode?

Photoconduction

Light excitation

Electro-emission

Photoemission (correct)

In the structure of the first-generation image intensifier, what is the composition of the input phosphor?

Cesium Iodide Signup and view all the answers

What is the primary function of the control grid in a television camera tube?

To form and accelerate the electron beam Signup and view all the answers

How does the photocathode respond to light stimulation?

By emitting electrons Signup and view all the answers

Which layers make up the target assembly in a television camera tube?

Window, signal plate, target Signup and view all the answers

What aspect of the concave input screen aids in image clarity?

It keeps the same distance between points. Signup and view all the answers

What is a primary advantage of using fiber optics for optical coupling in television camera systems?

It results in a compact assembly Signup and view all the answers

What happens to the image when it transitions from input to output phosphor?

It is reversed in orientation. Signup and view all the answers

When does the target assembly of a television camera tube create a video signal?

When it is illuminated Signup and view all the answers

What is the relationship between the intensity of light reaching the photocathode and the number of electrons emitted?

Directly proportional Signup and view all the answers

Which two types of camera tubes are most commonly used for fluoroscopy?

Vidicon and Plumbicon Signup and view all the answers

Where is the electron beam directed to after it passes through the wire mesh-like structure?

To the anode Signup and view all the answers

What does the window of a television camera tube usually measure?

2.5cm or 5cm Signup and view all the answers

What is the role of the anode in a television camera tube?

To accelerate the electrons to create a signal Signup and view all the answers

What is the main disadvantage of a lens system in imaging devices?

Cannot accommodate additional optics for certain cameras Signup and view all the answers

What is a requirement for accepting a cine or photoshot camera in fluoroscopy?

Lens coupling Signup and view all the answers

What does the objective lens do in a fluoroscopy system?

Converts light from the output phosphor into a parallel beam Signup and view all the answers

In a fluoroscopic imaging system, what happens to the beam before it reaches the television camera?

A portion is transmitted while the remainder is reflected to film Signup and view all the answers

Which of the following types of fluoroscopy provides a real-time display?

TV fluoroscopy Signup and view all the answers

What is indicated by the term 'lens coupling'?

The connection of a lens to a fluoroscopy device Signup and view all the answers

What is the primary purpose of beam-splitting in a fluoroscopy system?

To simultaneously view and record images Signup and view all the answers

Which of the following is a type of fluoroscopy mentioned?

Digital fluoroscopy Signup and view all the answers

What is the image acquisition rate during the first 3 seconds of the described imaging process?

2 images per second Signup and view all the answers

What causes unacceptable masking images during the imaging process?

Noise, motion, and technical factors Signup and view all the answers

In Time-Interval Difference mode, what is the primary advantage of using different masks for subtracted images?

Lower contrast than mask-mode imaging Signup and view all the answers

During the process, which phase generates better subtraction images when certain conditions are met?

Selecting image number 5 as the mask image Signup and view all the answers

What distinguishes TID imaging from other imaging techniques?

It provides a dynamic flow of contrast media Signup and view all the answers

What is a key feature of digital fluoroscopy that distinguishes it from conventional fluoroscopy?

Incorporation of a charge-coupled device (CCD) Signup and view all the answers

How does digital fluoroscopy minimize patient radiation dose?

Through last frame hold technology Signup and view all the answers

What operation mode does the X-ray tube use during digital fluoroscopy?

Pulse radiographic mode Signup and view all the answers

Which of the following is NOT a component of a digital fluoroscopy imaging system?

Analog film recording Signup and view all the answers

What does pulse-progressive fluoroscopy enhance in digital imaging?

Temporal frame averaging Signup and view all the answers

What type of manipulation tools are included in a digital fluoroscopy imaging system?

Trackball, joystick, and mouse Signup and view all the answers

What is a primary application of the charge-coupled device (CCD) in digital fluoroscopy?

Improving the sensitivity and resolution of image capture Signup and view all the answers

Which of the following refers to the time parameters involved in pulse-progressive fluoroscopy?

Interrogation, extinction, and duty time Signup and view all the answers

What is the primary purpose of using mask mode in image subtraction?

To store and utilize an initial image for contrast enhancement Signup and view all the answers

Which of the following best describes temporal subtraction?

It subtracts an image obtained at one time from an image obtained at a later time. Signup and view all the answers

What happens during the remasking process?

A subsequent image is used as the mask image due to inadequacies in the original. Signup and view all the answers

Which of the following accurately describes hybrid subtraction?

It combines temporal and energy subtraction techniques. Signup and view all the answers

In the context of digital fluoroscopy, what does the time interval display mode (TID) achieve?

It allows real-time monitoring of contrast passage. Signup and view all the answers

How is the amount of contrast for mask mode typically determined?

It is measured by timing the injection and acquiring the mask image after a delay. Signup and view all the answers

What is a significant advantage of using image subtraction in digital fluoroscopy?

It allows for immediate visualization of anatomical structures. Signup and view all the answers

Which statement accurately describes the function of digital fluoroscopy?

It provides better contrast resolution through image processing techniques. Signup and view all the answers

Study Notes

Introduction to Fluoroscopy and Digital Subtraction Angiography

Fluoroscopy is a method of obtaining images on a fluorescent screen.
It enables real-time imaging and visualization of anatomical structures and dynamic processes.
Fluoroscopy is used for positioning patients for image recordings and interventional procedures.
It allows examination from multiple positions to view abnormalities.
Angiography is a specialized type of fluoroscopy focusing on vessels.
Fluoroscopy is also used to view moving internal structures and fluids.

History of Fluoroscopy

Fluoroscopy was discovered in 1896 by Thomas Addison, utilizing barium platinocyanide as a screen phosphor.
Improvements such as modified II/TV systems with enhanced image brightness occurred in 1948.
Temporal and energy subtraction methods were developed in the 1960s.
Clinical DSA systems emerged in 1977, followed by improvements in image processing and qualitative enhancements.

Fluoroscopic Acquisition Components

The X-ray tube is typically positioned beneath the patient table.
An image intensifier is typically positioned above the patient table.
Some systems have the X-ray tube above and the image receptor below.
Imaging is sometimes operated remotely.
Visible light from the image intensifier is displayed on a monitor.
X-ray tubes operate at low mA.
Fluoroscopic examinations expose the patient to significantly higher radiation doses compared to static radiographic examinations.
kVp for procedures is dependent on the body part being examined.

Image Intensifier Tube

Image intensifier tubes are around 50 cm in length.
The tubes convert X-ray images into high-intensity visible light.
Components include a glass envelope, input phosphor, photocathode, electrostatic focusing lenses, and an output phosphor.
The glass envelope maintains vacuum for electron control.
Components are housed in metal to protect against breakage.

Input Phosphor

The input phosphor interacts with X-rays, converting them into visible light.
Cesium iodide (CsI) crystals are used as the input phosphor.
It forms a thin layer of closely packed, needle-like crystals.

Photocathode

The photocathode emits electrons in response to the light from the input phosphor.
It's composed of cesium and antimony compounds and is directly bonded to the input phosphor.
Electron number emitted is proportional to light intensity.

Electrostatic Focusing Lens

Electrostatic focusing lenses direct the flow of electrons to the output phosphor.
They reverse image position and maintain consistent distance between input and output screens.

Anode

The anode accelerates electrons for the passage to the output phosphor.
Typically charged with 25kV.

Output Phosphor

The output phosphor receives the accelerated electrons from the anode and converts them into a high-intensity light image.
Usually composed of zinc cadmium sulfide crystals.
Each electron arrival results in a considerable increase in light output.

Camera

Television cameras, including vidicon and plumbicon models, are utilized for fluoroscopy.
The camera housing system includes the required electromagnetic coils to direct and steer the electron beam accurately.
Glass encloses the internal components.
The electron gun is heated to emit a constant electron current.

Optical Coupling

Fiberoptics and lens systems enable coupling between the image intensifier and the camera.
Fiberoptic systems are more compact, allowing for easier movement of the imaging system.
Lens systems are often used with cine or photoshot cameras.

Types of Fluoroscopy

Direct fluoroscopy uses a fluorescent screen to view the X-ray image directly.
TV fluoroscopy uses an image intensifier to convert X-rays into light, which is then viewed on a television monitor.
Digital fluoroscopy (with image intensifiers and digital acquisition systems) uses image intensifiers along with digital image processing.

Digital Fluoroscopy Imaging System

Digital fluoroscopy systems acquire and process images digitally.
Systems use components like image intensifiers, cameras, and a computer.
Image acquisition is usually faster
Post-processing is performed digitally
Lower patient dose compared to earlier methods
Progressive fluoroscopy provides high quality images
Averaging of temporal frames improves image quality

Charge-Coupled Device (CCD)

CCDs are used in digital fluoroscopy as image detectors.
They are manufactured with high spatial resolutions and high signal-to-noise ratios.
Efficiently transmit light from scintillation phosphors, like CsI.
They're unaffected by magnetic fields and have linear response.

Flat Panel Image Receptor (FPIR)

FPIRs are newer digital image detectors.
Some use direct conversion while others use indirect conversion (where light capture and electron signal conversion is via a phosphor screen.)
FPIRs offer distortion-free images, consistent quality, and high dynamic range.

Image Display-Video System

Video image formation on monitors is similar in approach to other forms of image display but is optimized for digital fluoroscopy applications.
Traditional CRT displays have been replaced by AMLCDs (Active Matrix Liquid Crystal Displays) because they exhibit superior image quality, are smaller, provide distortion-free images, and have better contrast resolution.
Traditional CRTs display images interlaced, while newer methods are usually displayed progressively.
Higher signal-to-noise ratio (SNR) is a necessity in digital fluoroscopy.

Active Matrix Liquid Crystal Display (AMLCD)

AMLCDs are used for digital image display.
They offer better contrast and image quality compared to CRTs.
They reduce the effects of ambient light.

Total Process

The total process for digital fluoroscopy involves acquisition, processing, and display stages.
Signal processing is performed by the system hardware and software.

Digital Subtraction Angiography (DSA)

DSA is a specialized application of digital fluoroscopy for vascular diagnostics.
DSA utilizes subtraction techniques to provide clear visualization of blood vessels without direct arterial puncture.
DSA is a gold standard method for investigating vascular conditions like stenosis, aneurysms, and AVMs.
Roadmapping is a specialized type of DSA for catheter navigations.

Patient Dose

Digital fluoroscopy techniques can reduce patient dose.
Pulsed X-ray beam and imaging systems with higher sensitivity contribute to the lower dose.
Static images from digital fluoroscopy systems often exhibit lower per-frame radiation dose compared to analog fluoroscopy.

Summary and Advancements

Digital fluoroscopy replaced traditional methods due to its superior image quality and reduced patient dose.
Advancements in DSA include energy subtraction, which aims to simplify procedures.
Future developments in digital fluoroscopy may include more sophisticated subtraction techniques and improved image quality.

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Description

Explore the fascinating world of fluoroscopy and digital subtraction angiography in this quiz. Learn about its history, techniques, and applications in real-time imaging and medical procedures. Test your knowledge on how fluoroscopy has evolved over the years and its significance in modern medicine.