Image Processing
This matrix size will create smaller pixels and improve sharpness
What is a Larger matrix. The size of a matrix is defined by the number of rows and columns that it contains. EX. a matrix size of 3x4 will have 12 pixels and a matrix size of 12x12 will have 144 pixels. This larger matrix size improves image quality.
This type of equipment relies on excellent positioning skills and extensive knowledge of surface and internal anatomy because this part being radiographed must be accurately positioned over the ionization sensors.
What is the Automatic Exposure Control (AEC)- The AEC is used to provide consistency of radiographic quality
As you increase OID, this happens to contrast
Contrast increases by reducing the amount of scatter that reaches the receptor, scatter creates density which reduces the contrast ratio.
This type of grid contains lead strips that are parallel to one another and the x -ray tube may be angled along the length of the grid without cutoff.
What is a Linear Grid. This type of grid is used with a primarily large SID or small field.
This is the amount in inches that the secondary barrier should be in an x ray room.
What is 1/32 in. The primary barrier in an x -ray room should be thicker at 1/16 in. The primary barriers are any walls where the primary beam can be pointing to. The secondary barrier shields from scatter and leakage.
This is the universal protocol for PACS and contains the patients name, DOB and type of study.
What is DICOM. DICOM (Digital Imaging and Communications in Medicine) is a standard for handling, storing, printing, and transmitting information in medical imaging.
This type of equipment is also known as the variable transformer, its the source for selecting kVp, and provides for the variation of voltage flowing in the x-ray circuit and applied to the x-ray tube.
What is the Autotransformer
This will create few gray tones, mainly a black and white image. This may also be referred to as short-scale contrast.
What is High Contrast. High contrast is created by using low kVp.
This refers to the darkening of images by sources other than the radiation of the primary beam to which the film was exposed
What is radiation fog. Filter grids are used to reduce scattered noise and increase contrast in x-ray images.
This is the minimum requirement of lead used when being exposed to radiation.
What is 0.25mm of lead. Lead aprons reduce exposure of x-rays to vital organs that are potentially exposed to ionizing radiation during medical imaging that uses x-rays (radiography, fluoroscopy, computed tomography).
This is an image processing filter that enhances the edge contrast of an image in an attempt to improve its apparent sharpness.
What is edge enhancement. This processing filter works by identifying sharp edge boundaries in the image, such as the edge between a subject and a background of a contrasting color, and increasing the image contrast in the area immediately around the edge, creating subtle bright and dark highlights on either side.
The target of the x ray tube is made of this material
Tungsten. Tungsten is used because of its high atomic number, high melting point which increases the intensity if the x-rays.
In radiology this refers to the ability of the imaging modality to distinguish between differences in image intensity.
What is contrast resolution.The inherent contrast resolution of a digital image is given by the number of possible pixel values, and is defined as the number of bits per pixel value.
This has been used in digital radiography to indicate the relative speed and sensitivity of the digital receptor to incident X-rays and, ideally, to provide feedback to the technologist regarding the proper radiographic techniques for a specific exam that achieves an optimal image
What is Exposure Index.
This is a device that is attached to the opening of the x-ray tube housing to regulate the size and shape of an x-ray beam.
What is a beam restriction. Beam restrictions are used to protect the patient and to decrease scatter radiation.
EX. Aperture diaphragms,Cones,cylinders or Collimators
This is the process of combining multiple radiographic images with overlapping fields of view to produce a segmented panorama
What is image stitching. This is often used when the radiographer is unable to capture everything in one image so multiple images are taken with overlap. The stitching process can join the multiple images together.
In this type of radiography the image receptor is an imaging plate made of photostimulable phosphor (PSP) that is later placed in a reader unit which removes the IP so that is may be scanned by a laser
What is Computed Radiography (CR).
This is the difference in absorption based on shape or energy of x-ray beam
Subject contrast. This is the ratio of radiation intensities transmitted through different areas of the component being evaluated. ... Generating x-rays using a low kilovoltage will generally result in a radiograph with high contrast.
This can be present in a variety of ways including abnormal shadow noted on a radiograph or degraded image quality and have been produced by artificial means from hardware failure, operator error and software (post-processing)
What is Image Artifacts. Some common image artifacts are
*motion artifact- due to patient movement resulting in a distorted image
*detector image lag or ghosting- latent image from previous exposure present on the current exposure
*radiopaque objects on or external to the patient- such as necklaces, piercing, buttons, hair (pony tail, hair braids)
This is a plan of action to ensure that a diagnostic x-ray facility will produce consistent, high-quality images with a minimum of exposure to patients and personnel.
What is Quality Assurance. Quality Assurance address the following problems in Image quality assessment, Practical equipment checks and Image viewing checks
This is a graphical display of the pixel intensity distribution for a digital image.
What is a histogram. A Histogram plots the number of pixels found at each pixel value.The signal value peaks cover a relatively narrow range of pixel values, all of which are shifted to the right side of the histogram.
This equipment is used to convert low energy radiation into visible light images.
What is an image Intensifier. It is mostly seen in the detector portion of an x-ray c-arm, the image intensifier has a low scatter input portion comprised of low absorption substances such as titanium or aluminum that allows low-intensity x-rays to be converted to a conveniently bright visible light output.
Higher energy x-ray beams have lower_____ than x-ray beams with lower energy
What is attenuation. Attenuation is the reduction of the intensity of an x-ray beam as it travels through matter. This reduction may be caused by absorption or by scattering of photons from the beam and can be affected by different factors such as beam energy and atomic number of the object. X- rays that have a higher energy will pass through the patient more efficiently than a low energy x ray therefore attenuation will decrease.
This is caused by too few x-ray photons hitting the image receptor. It is a source of noise in the image.
What is Quantum mottle. Fewer photons reaching the image receptor will cause an undesirable fluctuation in image densities, resulting in images with a grainy, or sand-like, appearance.
Improper alignment of this will distort a radiographic image
What is central ray alignment. If the central ray is not properly aligned to the image receptor the image will appear distorted. The two types of distortion is size and shape.