Imaging Equipment Fall Final Part 2

The individual picture elements that contribute to the smallest segment of an image matrix are called pixels. Pixels are the smallest units of an image and they represent a single point in a digital image. Each pixel contains information about its color and brightness, and when combined together, they form the complete image.

The correct answer is minification ratio and flux gains. The minification ratio refers to the reduction in size of the image as it passes through the intensifier, which leads to an increase in brightness. Flux gains refer to the amplification of the incoming light signal by the intensifier, resulting in a higher level of brightness. These two factors play a significant role in determining the amount of brightness gain in an image intensifier.

Most modern image intensifiers utilize an input fluorescent screen layer composed of cesium iodide. Cesium iodide is commonly used in image intensifiers due to its high light output and good spatial resolution. It has excellent X-ray absorption properties and can efficiently convert X-ray photons into visible light photons, which can then be detected and amplified by the intensifier. This makes cesium iodide an ideal material for enhancing the brightness and clarity of images in medical imaging and other applications where low-light conditions need to be improved.

Vignetting refers to the reduction of brightness at the periphery of an image. In the context of an image intensified fluoroscope, vignetting occurs due to the limitations of the optical system, causing a decrease in brightness towards the edges of the displayed image. This can result in a loss of detail and clarity in the peripheral areas of the image. Therefore, vignetting is the correct term to describe the reduction of brightness at the periphery of an image displayed by an image intensified fluoroscope.

Cesium iodide is the most common material used in the formation of the input phosphor of a modern image intensifier. This is because cesium iodide has a high atomic number, which allows it to efficiently convert X-ray photons into visible light. It also has a high light output and good spatial resolution, making it ideal for medical imaging applications. Calcium tungstate, barium lead sulfate, and zinc cadmium sulfide are also used in image intensifiers, but cesium iodide is the most commonly used material.

The image intensifier is the device that receives the radiation exiting the patient and converts it into light. It then increases the brightness of the light, allowing for a clearer and more detailed image to be displayed. The cine camera, spot film camera, and television monitor are not involved in this process.

The electronic image formed on the surface of the photocathode needs to be converted into a visible light image by the output phosphor of the image intensifier. This is because the human eye is sensitive to visible light and can perceive images formed by it. The output phosphor helps in amplifying and converting the electronic image into a visible light image, allowing it to be viewed by the human eye.

Amorphous refers to a non-crystalline state of a material that is typically crystalline. In this state, the material lacks a regular and repeating atomic structure. This definition implies that the material does not have a well-defined shape or form, and its properties, such as optical, electrical, or thermal, may differ from those of the crystalline form.

Digital subtraction angiography (DSA) is a digital technique used to enhance the visualization of blood vessels by eliminating non-vascular structures. It involves taking two images, one before and one after the injection of a contrast agent. By subtracting the pre-contrast image from the post-contrast image, the non-vascular structures are eliminated, leaving only the enhanced sacular structures visible. This technique is commonly used in diagnostic imaging to evaluate blood flow and detect abnormalities in the vasculature.

The correct answer is adaption time. Adaption time refers to the duration it takes for the human eye to adjust to the low light levels of conventional fluoroscopy. During this time, the eye gradually becomes more sensitive to the dim light, allowing for better visibility and clarity. This adjustment period is necessary to ensure accurate interpretation of the images produced during fluoroscopy procedures.

Electrostatic lenses control the path of electron flow from the photocathode to the output phosphor in the image intensification tube. These lenses use electric fields to manipulate the electrons and focus them onto the output phosphor, ensuring that the image remains clear and sharp. The accelerating anode, vacuum glass envelope, and input phosphor also play important roles in the functioning of the image intensification tube, but they do not directly control the path of electron flow.

An image intensifier is used in most modern systems to achieve a substantial increase in conventional fluoroscopic brightness levels. This device works by amplifying the incoming X-ray photons and converting them into visible light, which results in a brighter image. By increasing the brightness levels, the image intensifier improves the visibility and clarity of the fluoroscopic images, allowing for better visualization of anatomical structures and abnormalities.

The usual range of milliamperage required for an image intensified fluoroscopy is about 1-5 mA. This range is considered appropriate for this procedure as it provides sufficient image quality while minimizing the radiation dose to the patient. Higher milliamperage settings may result in higher radiation exposure, which is not ideal for the patient's safety. Therefore, the range of 1-5 mA is commonly used to balance image quality and radiation dose in image intensified fluoroscopy.

The photocathode is the part of the image intensifier tube that functions to change the visible light image into an electronic image. It is a photosensitive material that emits electrons when exposed to light. These emitted electrons are then accelerated and focused to create an electronic image, which can be amplified and displayed on a screen. The photocathode plays a crucial role in the conversion process, as it is responsible for initiating the electronic signal that represents the visible light image.

A laser printer is the most frequently used device for the production of a hard copy image in radiology. Laser printers use laser technology to produce high-quality prints quickly and efficiently. They are capable of printing images with great precision and detail, making them ideal for radiology purposes where accurate representation of medical images is crucial. Laser printers also offer the advantage of being able to print on a variety of media types, including special radiology film, which is necessary for producing hard copy images in radiology.

Photostimulable luminescence refers to the process by which the trapped energy of the electronic latent image is released as a visible light image. This process occurs in photostimulable phosphor plates used in computed radiography. When the plate is exposed to radiation, the energy is absorbed into the lattice of a fluorescent crystal. This energy is then trapped in the form of an electronic latent image. When the plate is scanned with a laser beam, the trapped energy is released as visible light, which is detected and converted into a usable electronic signal by a photomultiplier tube.

The correct answer is an array of thin-film transistors (TFT's). In digital radiographic imaging using either amorphous selenium or cesium iodide amorphous silicon, the latent image is formed by an electronic signal. This signal is stored by an array of thin-film transistors (TFT's). These transistors act as switches, controlling the flow of electrical current and storing the electronic signal that represents the image. The use of TFT's allows for efficient and accurate capture and storage of the image data.

Radiographic spot film is the correct answer because it provides the greatest recorded detail. Radiographic spot films are high-resolution X-ray films that are used to capture detailed images of specific areas of the body. They are designed to provide maximum clarity and detail, making them ideal for diagnosing and evaluating various medical conditions. Cinefluorography spot film, video tape spot film, and kenescopic spot film are not specifically designed for capturing detailed images and may not provide the same level of clarity and detail as radiographic spot film.

When a thin layer of amorphous selenium is struck by an x-ray photon in a direct-to-digital radiographic (DDR) imaging system, the net result is an electron-hole pair that is detected by an array of thin-film transistors (TFT's). This is because the x-ray photon transfers energy to the amorphous selenium, causing the creation of an electron-hole pair. The array of thin-film transistors (TFT's) is designed to detect and measure the electrical signals generated by the movement of these charges, allowing for the conversion of the x-ray image into a digital format for further processing and analysis.

The electronic signal that carries the information generated in the television camera to the cathode-ray tube (TV monitor) is called the video signal. This signal contains the visual information that is displayed on the screen, such as images and motion. It is responsible for transmitting the video content from the camera to the monitor, allowing us to see the images and videos on our television screens.

The correct answer is "indirect electronic radiography (IER)" because all the other terms mentioned in the question - direct-to-digital radiography (DDR), digital fluoroscopy (DF), and computed radiography (CR) - are used to describe techniques for digital imaging in radiography. Indirect electronic radiography is not a commonly used term in the field.

The correct answer is 2 and 3. The input side of an image intensifier tube consists of a photocathode, which converts incoming photons into electrons, and a fluorescent screen, which converts the electrons back into photons to create a brighter image. The incandescent screen is not found on the input side of the tube, but rather on the output side to further amplify the brightness of the image.

Television camera tubes are the most commonly employed devices for a modern radiography department. These tubes are used to capture and transmit images in real-time, allowing for immediate viewing and analysis. They are essential for various applications, including fluoroscopy and cinefluoroscopy, where continuous imaging is required. The vidicon and plumbicon are specific types of television camera tubes that are commonly used in radiography. These tubes convert the light from the X-ray image intensifier into an electrical signal, which can then be processed and displayed on a monitor for diagnostic purposes.

After a photostimulated luminescent phosphor (PSP) of a CR imaging system has been scanned by the photomultiplier (PM tube reader, the plate is exposed to a high intensity light to clear any of the remaining latent image from the image plate. This process is necessary to ensure that the image plate is ready for the next scan and that any traces of the previous image are removed. By clearing the latent image, the image plate is reset and ready to capture a new image.

During televised image intensified fluoroscopy, permanent static images or spot films can be produced and recorded using photo-spot imaging, cassette-loaded spot imaging, and video tape recordings. This means that all three options (1, 2, and 3) are correct as they all allow for the production and recording of permanent static images or spot films during televised image intensified fluoroscopy.

A change in the window level of a digital display refers to adjusting the brightness or density of the image being displayed. This means that the correct answer is digital density or brightness of the image. Window level controls the overall brightness of the image, making it darker or lighter. It does not affect the size distortion, noise level, or contrast of the image.

The visible light image that impinges upon the target of a television camera tube is converted into an electronic image. This conversion process involves capturing the light through the camera lens and then converting it into electrical signals that can be processed and displayed on a screen or monitor. The electronic image is then transmitted or stored for viewing or further manipulation.

Most modern image intensifier tubes operate at an operating potential of approximately 25 kV. This voltage level is sufficient to accelerate electrons and create a focused electron beam, which then interacts with the input phosphor to produce an intensified image. Higher voltages can lead to better image quality and brightness, but they also increase power consumption and can cause damage to the tube. Therefore, 25 kV is a commonly used and optimal operating potential for image intensifier tubes.

Radiographic film is capable of the highest resolution among the given options. This is because radiographic film has a higher sensitivity to X-rays, allowing it to capture more detailed images with finer resolution. The human eye has limitations in perceiving fine details, while intensifying screens and fluoroscopic screens are used to enhance the visibility of X-ray images but do not provide the same level of resolution as radiographic film.

A charged-coupled device (CCD) has several advantages over a television camera tube, including greater sensitivity at lower light levels, smaller size, and less sensitivity to mechanical stresses. However, it is not associated with a reduced contrast resolution or low contrast detectability. This means that a CCD is capable of capturing images with high contrast and resolution, making it a preferred choice in applications where these factors are important.

Amorphous silicon releases electrons when struck by light photons, while amorphous selenium releases electrons when struck by x-ray photons.

The correct answer is a higher speed of spot image acquisition and the ability to post process the image. This is because digital fluoroscopy allows for faster image acquisition, which is beneficial in capturing dynamic processes in real-time. Additionally, digital images can be post-processed to enhance image quality, adjust contrast, and apply various filters or measurements, providing greater flexibility and diagnostic accuracy.

An insufficient amount of radiation during a digital radiographic examination leads to an increase in the amount of quantum mottle on the image. Quantum mottle refers to the random variation in the number of x-ray photons reaching the image receptor, resulting in a grainy appearance. When there is not enough radiation, fewer photons interact with the receptor, leading to a higher level of quantum mottle and a decrease in image quality.

Most modern indirect-to-digital radiographic (IDR) imaging systems have a sensitivity that is comparable to an 800 speed film-screen combination. This means that both the IDR imaging systems and the 800 speed film-screen combination have similar capabilities in capturing and producing high-quality images.

The correct answer is 25% per hour after the initial exposure. This means that the image on a photostrimulable phosphor plate (PSP) of a CR imaging system will fade at a rate of 25% per hour within 8 hours of the exposure. This indicates that the image will gradually become less visible over time, losing a quarter of its intensity every hour.

The principle advantage of image intensified fluoroscopy compared to conventional fluoroscopy is increased image brightness. Image intensified fluoroscopy uses an intensifier tube to amplify the brightness of the image, allowing for better visualization of structures and details. This increased brightness improves the overall image quality and enhances the ability to accurately diagnose and interpret the image.

The release of trapped energy in a meta-stable F center (Europium electron holes) of a BaFBr crystal in the photostimulable phosphor imaging plate (PSP) of a CR imaging system is triggered by the exposure to visible (laser) light. The specific wavelength of light that triggers this release is in the red spectrum.

The total brightness gain for a modern image intensifier fluoroscopic image is significantly higher compared to a conventional fluoroscopic screen image. This is because a modern image intensifier uses advanced technology to amplify the incoming light, resulting in a much brighter image. The answer option of 5000-30000 times indicates the substantial increase in brightness achieved by the image intensifier.

In a coherent event, the incident photon transfers all of its energy to the electron, causing it to be ejected from its orbit. The scattered photon has the same energy as the incident photon. In this scenario, the incident photon has an energy of 37 keV, which matches the energy of the scattered photon. Therefore, this is a coherent event.

Image intensified fluoroscopic technique allows for the visualization of dynamic motion of the tissue. This means that it can capture real-time images of moving structures, such as the beating of the heart or the movement of joints. Routine radiographic imaging, on the other hand, captures still images and does not show the motion of the tissue. Therefore, the principle advantage of image intensified fluoroscopic technique compared to routine radiographic imaging is the ability to visualize dynamic motion of the tissue.

The correct answer is 1/30 second. This is because the human eye has a certain integration time, which means it takes a certain amount of time for the eye to perceive and process an image. In order to create a smooth and continuous moving image on a television screen, each frame must be presented within this integration time. Presenting each frame in less than 1/30 second ensures that the frames are presented quickly enough for the human eye to perceive them as a continuous motion.

Digital imaging has the advantage of more exposure latitude compared to conventional imaging. Exposure latitude refers to the ability to capture a wider range of light intensities without losing detail in the highlights or shadows. In digital imaging, the sensor can capture a greater range of light, allowing for better control over exposure and ensuring that details are not lost in areas of high contrast. This is particularly beneficial in situations where there is a wide range of light intensities, such as in high-contrast scenes or when photographing subjects with both bright and dark areas.

The sensitivity of most computed radiographic (CR) imaging systems is about the same as a 200 speed film-screen combo. This means that both the CR imaging systems and the 200 speed film-screen combo have similar capabilities in capturing and producing high-quality images. The sensitivity refers to the ability of the imaging system to detect and record the radiation exposure, and a higher speed film-screen combo would indicate a greater sensitivity. Therefore, the fact that the sensitivity of CR imaging systems is about the same as a 200 speed film-screen combo suggests that CR systems are capable of producing high-quality images.