R102 Final Exam Study Guide
Chapter 1
Who discovered x-rays?
A german physicist name Dr, Wilhelm Roentgen in 1895
What type of low vacuum glass tube did Roentgen use in his experiment?
Crooks Tube
Define fluorescence.
the instantaneous production of light resulting from the interaction of some type of energy(x-rays) and some type of element or compound (barium platinocyanide)
What does the x in x-ray stand for?
the mathematical symbol for the unknown
What was the world’s first x-ray of?
it was of Roentgens wifes hand
When were the first harmful effects of x-rays realized?
1898, was first noticed as a reddening and burning of the skin who were exposed to large doses of x-rays required at that time
Define energy.
ability to do work and it can exist in different forms such as electrical energy, kinetic energy, thermal energy, and electromagnetic energy
X-rays are a form of what kind of radiation?
electromagnetic radiation
Why are X-rays said to have a dual nature?
they act like both waves and particles
X-rays can be described as waves because they have a ____ and a ___.
wavelength and a frequency
In a vacuum, how fast do x-rays travel?
speed of light
Which waves are more powerful? High frequency or low frequency?
high frequency
What is exposure, absorbed dose and dose equivalent?
exposure: measures the amount of ionization or electrical charge in a specified amount of air, the intensity of radiation exposure, expressed in (R) … another radiation quantity to express exposure is air kerma
absorbed dose: the rad and gray units measuring the transfer of radiation energy into matter. One rad is equal to the energy transfer of 100 ergs per gram if any absorbing matter
dose equivalent: units used in measuring occupational radiation exposure. One sievert equals 100 rem or 0.01 Sv equals 1 rem
What does air kerma (Gy), gray (Gy), Sievert (Sv), and becquerel (Bq) measure?
air kerma (Gy) : the amount of energy deposited in a unit mass of air (kg) and expressed in units of joules (J) or J/kg, which is also the radiation unit, the gray(Gy)
gray (Gy): absorbed radiation dose, one gray is defined as 1 joule of energy absorbed in each kilogram of absorbing material, the amount of ionizing radiation energy absorbed per unit mass of matter, typically tissue.
Sievert (Sv) : unit of measurement for radiation dose equivalent, which reflects the biological effects of ionizing radiation on human tissue. Unlike the gray (Gy), which measures the absorbed dose of radiation energy, the sievert incorporates a weighting factor to account for the type of radiation and its biological impact.
becquerel(Bq): SI unit of radioactivity, which measures the rate at which a quantity of radioactive material undergoes decay. Specifically, it represents the number of nuclear disintegrations occurring per second.
What does ALARA stand for
As Low As Reasonably Achievable
What are the cardinal principles for minimizing radiation dose?
Time, Distance, Shielding
What are the three primary exposure factors?
kVp, mA, Time
Chapter 2
What is the cathode?
a negatively charged electrode, comprised of a filament and a focusing cup
What is the anode?
a positively charged electrode, composed of molybdenum, copper, tungsten, and graphite.. the anode consists of a target and, in rotating anode tubes, a stator and rotor
What is the glass envelope?
the thing that houses the necessary components for x-ray production, It is a sealed, vacuum-tight container that encases the cathode (filament) and anode (target), The glass is designed to withstand high temperatures generated during x-ray production and prevent cracking or thermal damage.
Be able to label the filament, focusing cup, glass envelope, anode and cathode.
What is off focus radiation?
occurs when projectile electrons are reflected and x-rays are produced outside the focal spot
What is the source of electrons during x-ray production?
the cathode
What is the purpose of the focusing cup?
to focus the stream of electrons from the filament toward the anode target
What are the two types of anodes?
stationary and rotating
What is the benefit of a rotating anode?
they can withstand high heat loads, A rotating anode spreads the heat generated during x-ray production over a larger surface area, preventing overheating and allowing higher exposure techniques for better image quality and tube longevity.
In the x-ray tube, what are the two target interactions that produce x-rays?
Bremsstrahlung and Characteristic
What is Bremsstrahlung radiation? (know the process)
german word meaning breaking or slowing down radiation.. occurs when a projectile (incident) electron completely avoids the orbital electrons of a tungsten atom and travels very close to its nucleus.. the very strong electrostatic force of the positively charged nucleus causes the negatively charged electron to suddenly slow down.. as the electron looses energy it suddenly changes direction and the energy loss then reappears as an x-ray photon.. the closer the projectile electron is to the nucleus the stronger the attraction.. the stronger the attraction the more energy the projectile electron loses and the stronger the resultant x-ray photon (higher energy).. projectile electrons that travel farther from the nucleus create x-ray photons with less energy
What is Characteristic Radiation? (know the process)
produced when a projectile electron interacts with an electron from the inner shell (K-shell) of the tungsten atom.. characteristic x-rays can be produced in a tungsten target when the kVp is set to 70 or greater because of the binding energy of the k-shell electron is 69.5 keV
What is a dead man switch?
the switches used to make an x-ray.. require positive pressure to be applied during the entire x-ray exposure process.. if the radiographer lets off the switch then the x-ray is terminated
What does quality refer to?
kVp.. the speed of the electrons in the tube current determine the quality or energy of the x-rays that are produced.. the energy level of the radiation produced.. penetrating ability or energy of the x-ray beam
What does quantity refer to?
number of x-rays in the beam, also known as the intensity or output of the beam. It is primarily controlled by the mAs setting, which determines the number of electrons available to produce x-rays.
What does kVp determine?
beam penetrability.. the speed at which the electrons in the tube current move
What does mA measure?
operate the tube current.. tube current is the number of electrons flowing per unit time between the cathode and the anode
What is time?
the length of time over which the x-ray tube produces x-rays.. the exposure time can be set by the radiographer can be expressed in seconds or milliseconds as either a fraction or a decimal.. determines the length of time for which the tube current is allowed to flow from cathode to anode.. the longer exposure time the greater the quantity of electrons that flow from cathode to anode and the greater the quantity of x-rays produced
What is the anode heel effect
the x-ray beam has greater intensity (number of x-rays) on the cathode side of the tube with the intensity diminishing (lower intensity) toward the anode side.. the heel affect occurs because of the angle of the target
What is inherent filtration?
filtration that is permanently in the path of the x-ray beam.. three components contribute 1. the glass envelope of the tube 2. the oil that surrounds the tube 3. the window in the tube housing
What are compensating filters?
special filters added to the primary beam to alter its intensity.. these types of filters are used to image anatomic areas that are non-uniform in makeup and assist in producing more consistent exposure to the image
Chapter 3
What is attenuation?
reduction in the energy or number of the primary x-ray beam as it passes through the anatomic tissue
What are three things that happen to x-ray photons when they interact with the body?
absorption, scattering, transmission
What are the three types of photon interactions that may be responsible for absorption or scattering?
photoelectric effect, compton, coherent
What happens in the photoelectric effect? (know the process)
complete absorption of the incoming x-ray photon occurs when it has enough energy to remove (eject) an inner-shell electron. the ionized atom has a vacancy, or electron hole, in its inner shell and an electron from an outer shell drops down to fill the hole
What happens with coherent scattering? (know the process)
an interaction that occurs with low-energy x-rays, typically below the diagnostic range. the incoming photon interacts with the atom, causing it to become excited. the x-ray does not lose energy but changes direction
What happens with Compton scattering? (know the process)
the loss of energy of the incoming photon when ut ejects an outer shell electron from the atom.. the remaining lower energy x-ray photon changes direction and may leave the anatomic part (BAD VERY BAD)
What are four things that affect how often various interactions occur?
tissue thickness, type of tissue, x-ray beam quality, transmission
What is the remnant beam or exit radiation composed of?
composed of both transmitted and scattered radiation
What creates an image on the image receptor? (i.e. absorbed, transmitted, or scattered radiation).
transmitted
What is a latent image?
the invisible image.. not visible until it is processed to produce the manifest image or the visible image
When referring to a radiograph, what does brightness and contrast mean?
the amount of luminance of a display monitor.. the radiographic image must have sufficient brightness to visualize the anatomic structures of interest. contrast is a difference in brightness levels (grays) to be able to differentiate among anatomic tissue
What is spatial resolution?
term used to evaluate the accuracy of the anatomic structural lines displayed.. refers to the smallest object that can be detected in an image
Be able to recognize high and low spatial resolution?
What are the two types of distortion?
size and shape
What are the factors that determine the amount of image distortion?
scatter, quantum noise, image artifacts,
What is quantum noise?
brightness fluctuations in the image.. TV static
Be able to recognize quantum noise.
What is an artifact?
any unwanted brightness level on a radiographic image.. like a necklace, bra clasps, belts, buttons on jeans, lines attached at the hospital
Chapter 4
What are two type of digital radiography systems
computed radiography and direct radiography
What is a matrix?
combination of rows and columns (array) of small, usually square, "“picture elements” called pixels
What is a pixel?
the smallest component of the matrix also known as picture element
The more pixels, the ____ the picture.
better
What does the bit depth do?
determines the amount of precision in digitizing the analog signal and therefore the number of shades of gray that can be displayed in the image
How is the imaging plate erased in CR?
After the plate is scanned, residual latent image information may still remain in the photostimulable phosphor layer, The CR system exposes the plate to a bright, intense light source, which releases any remaining trapped electrons in the phosphor layer, This light exposure clears the plate, ensuring it is ready for reuse without any residual image artifacts that might interfere with future imaging.
What does PACS stand for?
picture archival and communication system .. a computer system designed for digital imaging that can receive, store, distribute, and display digital images
Know the difference between direct conversion and indirect conversion digital
radiography.
Direct and indirect conversion in digital radiography (DR) refer to the processes by which x-ray energy is converted into a digital image. Here's the difference:
Direct Conversion
Process:
X-rays are directly converted into an electrical signal.
This is achieved using a photoconductor material, typically amorphous selenium (a-Se).
When x-rays strike the photoconductor, they generate electron-hole pairs. The electrons are collected by a thin-film transistor (TFT) array, creating a digital signal.
Key Characteristics:
No intermediate light stage: This minimizes signal loss and improves spatial resolution.
Higher detail and sharper images compared to indirect systems.
More sensitive to small details in high-resolution imaging tasks.
Applications: Often used in applications requiring high spatial resolution, such as mammography.
Indirect Conversion
Process:
X-rays are first converted into visible light using a scintillator, typically made of cesium iodide (CsI) or gadolinium oxysulfide (Gd₂O₂S).
The visible light is then converted into an electrical signal by a photodetector (e.g., a photodiode array or CCD).
Key Characteristics:
Two-step process (x-rays → light → electrical signal): This can introduce some loss of spatial resolution due to light scattering in the scintillator.
Often more sensitive to x-rays, resulting in better performance at lower doses.
Generally more affordable and versatile than direct systems.
Applications: Commonly used in general radiography and portable systems due to cost-effectiveness and adequate image quality.
Comparison Table
Aspect | Direct Conversion | Indirect Conversion |
Conversion Process | X-rays → Electrical signal | X-rays → Light → Electrical signal |
Primary Material | Amorphous selenium (a-Se) | Cesium iodide (CsI) or Gadolinium oxysulfide (Gd₂O₂S) |
Resolution | Higher (no light scattering) | Slightly lower (light scattering) |
Dose Efficiency | Moderate | Higher (better sensitivity) |
Cost | Higher | Lower |
Applications | Mammography, high-detail imaging | General radiography, portable systems |
Each system has its strengths, and the choice depends on clinical needs, cost considerations, and specific imaging applications.
Know the general process of how the latent image is extracted from the CR IP within the reader.
The process of extracting the latent image from a Computed Radiography (CR) imaging plate (IP) within the reader involves several steps:
1. Loading the Imaging Plate
The imaging plate, which contains the latent image stored in its photostimulable phosphor layer, is inserted into the CR reader.
The reader removes the plate from its cassette for processing.
2. Scanning with a Laser Beam
A finely focused red laser beam scans the surface of the imaging plate in a raster pattern.
The laser provides energy to release the trapped electrons within the phosphor layer.
3. Photostimulable Luminescence (PSL)
As the laser beam stimulates the phosphor layer, the trapped electrons return to their ground state, emitting blue-violet light (photostimulable luminescence).
The intensity of the emitted light corresponds to the amount of x-ray energy absorbed at each point, creating a representation of the latent image.
4. Light Detection and Conversion
The emitted light is collected by a light guide and directed to a photomultiplier tube (PMT) or a similar light sensor.
The PMT amplifies the light signal and converts it into an electrical signal.
5. Analog-to-Digital Conversion (ADC)
The electrical signal is digitized using an analog-to-digital converter (ADC).
The digital data represent the x-ray exposure as a pixel matrix, where each pixel value corresponds to the intensity of the x-ray energy at that point.
6. Image Processing
The digital image data are processed for optimization, including contrast enhancement, edge sharpening, and noise reduction.
The final digital image is then displayed on a monitor for diagnosis or stored in a PACS (Picture Archiving and Communication System).
7. Erasing the Plate
After the latent image is read, the imaging plate is exposed to a bright intense light (usually white or UV light) to erase any residual image.
The plate is reset and ready for reuse.
This process ensures that the latent x-ray image stored in the phosphor layer is accurately captured and converted into a high-quality digital image for diagnostic purposes.
Chapter 6
What is an exposure indicator?
a numeric value that is displayed on the processed image to indicate the level of x-ray exposure received on the digital image receptor
What is the 15% rule?
rule stating that changing the kVp by 15% has the same effect on image receptor exposure as doubling or halving the mAs
The relationship between focal spot and spatial resolution.
as focal spot size increases, unsharpness increases and spatial resolution decreases: as focal spot size decreases, unsharpness decreases and spatial resolution increases
The relationship between SID and x-ray beam intensity.
as SID increases, the x-ray beam intensity becomes spread over a large area. This decreases the overall intensity of the x-ray beam reaching the IR
The relationship between SID and size distortion.
As SID increases, size distortion (magnification) decreases and spatial resolution increases; as SID decreases, size distortion(magnification) increases, and spatial resolution decreases
The relationship between OID and size distortion.
Increasing OID increases magnification and decreases spatial resolution; whereas decreasing OID decreases magnification and increases spatial resolution
What does a grid do to scatter and contrast.
Grid limit the amount of scatter radiation that reaches the IR and it increasing the contrast
What changes need to be made to the technique when adding a grid?
adjusting the mAs to maintain IR exposure
What changes need to be made to the technique when taking away a grid?
the mAs must be divided by the correct conversion grid factor to compensate for the increase in exposure
What does tube filtration do to the radiation quantity and energy of the beam?
increasing tube filtration decreases radiation quantity and increases the average energy of the x-ray beam. Decreasing tube filtration increases radiation quantity and decreases the average energy of the x-ray beam
Given a formula, be able to calculate inverse square law, mAs/distance compensation, 15%, grid conversion, and magnification.
Chapter 7
Explain what scatter is and how it affects image quality.
the result of compton interactions, the incoming x-ray photon loses energy and changes direction. affects image quality because it makes the image look foggy
Describe the relationship between kVp, tissue thickness, and x-ray beam field size as it relates to the production of scatter.
The production of scatter radiation in x-ray imaging is influenced by factors like kVp, tissue thickness, and x-ray beam field size. Here's how they relate:
1. Kilovoltage Peak (kVp)
Higher kVp:
Increases the energy of x-ray photons, which enhances their ability to penetrate tissues.
Higher energy photons are more likely to undergo Compton scattering, the primary mechanism of scatter production.
As kVp increases, scatter radiation increases because more photons interact with the patient's tissues through scattering rather than being absorbed.
Lower kVp:
Reduces photon energy, leading to more photoelectric absorption and less scatter.
However, lower kVp increases patient dose and may reduce image penetration.
2. Tissue Thickness
Thicker tissues:
More tissue volume increases the number of interactions between x-ray photons and matter.
This results in a higher probability of scatter radiation production because more photons are subject to Compton scattering.
Thinner tissues:
Less tissue interaction means less scatter production.
Imaging thinner parts of the body typically results in images with better contrast due to reduced scatter.
3. X-Ray Beam Field Size
Larger field size:
Covers a greater area of tissue, increasing the volume of matter the beam interacts with.
This leads to more scatter production due to the larger number of interactions.
Larger fields also increase patient dose and reduce image contrast.
Smaller field size:
Reduces the volume of irradiated tissue, limiting scatter production.
Improves image quality by maintaining higher contrast and reducing unnecessary exposure to surrounding tissues.
Interrelationship
In practice:
When imaging thicker tissues, increasing kVp might be necessary for adequate penetration, but this also increases scatter.
Reducing the field size using collimation is crucial to limit scatter from larger tissue volumes.
Balancing kVp, field size, and tissue thickness is key to optimizing image quality and minimizing scatter radiation.
Scatter Management Techniques
Collimation: Reduces field size, lowering scatter production.
Grids: Absorb scatter before it reaches the image receptor, improving contrast.
Proper kVp Selection: Use the lowest kVp that provides adequate penetration for the tissue being imaged.
Understanding these relationships helps radiologic technologists minimize scatter radiation and optimize image quality.
Explain beam restriction (collimation) and describe its impact on patient dose,
radiographic contrast, scatter production, IR exposure, and patient dose (Review Table 7-1, p. 176).pt dose decreases, scatter radiation decreases, radiographic contrast increases, exposure to the IR decreases
List the various types of beam restricting devices.
Aperture diaphragms, cones and cylinders, collimators, automatic collimators
Explain automatic collimation/PBL.
automatically limits the size and shape of the primary beam to the size and shape of the IR
Describe the construction of a radiographic grid.
consisting of very thin lead strips with radiolucent interspaces intended to absorb scatter radiation emitted from the patient .. the thin lead strips have a precise height, thickness, and space between them .. radiolucent interspace material separates the lead lines typically made of aluminum
Describe the relationship between radiographic grids and patient dose, radiographic
contrast and the amount of scatter that reaches the IR.Radiographic grids improve image quality by reducing scatter reaching the image receptor (IR), which enhances radiographic contrast. However, using grids increases patient dose because a higher exposure (mAs) is required to maintain image brightness due to the grid absorbing some primary radiation along with scatter.
Define terms related to grids: grid frequency, grid ratio, grid focus, focal range.
Grid Frequency: expresses the number of lead lines per unit length inches, or centimeters, or both. grid frequencies can range from 25-45 lines/cm (60-110 lines/in)
Grid ratio: the ratio of the height of the lead strips to the distance between them
Grid Focus: the orientation of the lead lines to one another
Focal Range the recommended range of SIDs that can be used with a focused grid. the convergent line or point always falls within the focal range
Describe the various grid patterns (ppt. slide 24).
linear: lead strips parallel to each other .. most popular, allows for some angulation of the tube
crossed: lead strips that run at right angles to each other .. remove more scatter than lines, limited because tube cannot angle due to possible grid cutoff
Differentiate between a parallel and a focused grid.
Parallel: lines run parallel to one another(straight up and down)
Focused: lines are angled to match the divergence of the primary beam
Explain why there are short and long dimension grids.
Short and long-dimension grids refer to the orientation of the grid lines relative to the grid's length.
Short-dimension grids have grid lines running perpendicular to the long axis and are used when imaging with the IR positioned crosswise (e.g., for portable chest x-rays).
Long-dimension grids have grid lines running parallel to the long axis and are ideal for standard imaging with the IR lengthwise.
These designs help match grid orientation to the positioning needs, minimizing grid cutoff and optimizing scatter reduction.
Apply all formulas presented in the chapter:
Calculating grid ratio
Grid Conversion Factor (GCF)
Adding and removing grids and calculating new mAsDescribe grid positioning errors to include: off-level grid, upside down grid, off-center
grid, off-focus grid (Box 7-3, p. 195)Upside-down focused grid: placing a focused grid upside down on the IR
Off-level error: angling the x-ray tube across the grid lines or angling the grid itself during exposure
off center error: the center of the x-ray beam is not aligned from side to side with the center of a focused grid
off focus error: using an SID outside the focal range
Review the chapter summary and the review questions
Chapter 8
What is AEC?
automatic exposure control .. a system used to consistently control the amount of radiation reaching the image receptor by terminating the length of exposure
What 4 things can limit the effectiveness of an AEC?
Four factors that can limit the effectiveness of an Automatic Exposure Control (AEC) system are:
Incorrect Detector Selection: Using the wrong AEC chamber for the anatomy being imaged can lead to over- or underexposure.
Improper Patient Positioning: Misaligning the anatomy with the AEC detectors may cause the system to terminate exposure prematurely or too late.
Presence of Prosthetics or Foreign Objects: High-density materials can alter the exposure time, resulting in incorrect image brightness.
Inappropriate Backup Timer Settings: If the backup timer is set too low, it may terminate the exposure prematurely; if too high, it risks overexposure in case of AEC failure.
Proper technique and awareness of these factors ensure AEC effectiveness.
What are the two types of AEC?
phototimers and ionization chamber systems
What is the mA readout, minimum response time, and back up time?
mAs readout: the actual mAs used for the image is displayed immediately after the AEC exposure, sometimes for only a few seconds
minimum response time: the shortest exposure time that the AEC system can produce
back up time: the maximum length of time for which the x-ray exposure continues when using an AEC system
If you choose the wrong detectors for a chest x-ray, what happens?
could result in either underexposure or overexposure to the IR
If you improperly center over a detector, what would happen?
the anatomy that in incorrectly centered will be bright while the anatomy that is needed will be harder to see .. under or over expose the IR
Name four conditions that may affect the exposure termination.
patient considerations, collimation, image receptor variations, calibration
What are Anatomically Programmed Techniques?
radiographic system that allows the radiographer to select a particular button on the control panel that represents an anatomic area for which a preprogrammed set of exposure factors are displayed and can be selected
What is an exposure technique chart?
pre-established guidelines used by the radiographer to select standardized manual or AEC exposure factors for each type of radiographic examination
What special considerations must be taken for pediatric patients?
they require less kVp and mAs due to their size, PEDS may not adequately cover the AEC detector and therefore manual exposure technique should be set, exposure factors for the adult skull can be used for pediatric patients aged 6 years and older.. exposure factors must be modified for patients 6 and younger.. it is recommended for the radiographer to modify the kVp by 15% to compensate for this lack of bone density
What special considerations must be taken for geriatric patients?
prepare to provide enhanced patient care in terms of additional time for imaging procedures; sensitivity to patient comfort by using table pad, positioning sponges and blankest for warmth .. exposure techniques may need to be decreased for pateints who appear thin and frail
Which would need a change in technique: a plaster cast? Fiberglass cast?
plaster cast
What is an additive and destructive disease?
Additive Disease: Increases tissue density (e.g., pneumonia, tumor), requiring more x-ray exposure (higher kVp) to penetrate the area.
Destructive Disease: Decreases tissue density (e.g., emphysema, osteoporosis), requiring less x-ray exposure (lower kVp) to avoid over-penetration.
What is an example of a positive and negative contrast?
Positive Contrast: Barium or iodine-based agents, which appear white on images due to their high atomic number.
Negative Contrast: Air or carbon dioxide, which appear black on images due to their low density and atomic number.
Chapter 10
What is fluoroscopy
allows imaging of the movement of internal structures. it differs from fil-screen imaging in that it uses a continuous beam of x-rays to create images of moving internal structures that can be viewed on a television monitor
Who is credited with inventing fluoroscopy?
Thomas Edison
What was wrong with early fluoroscopy?
it was very dangerous, high radiation dose for the patient and for the doctor, the patients anatomy would be in front of the x-ray source and the doctor would be in front of the patient
By the 1950s, what device enable fluoroscopic images to be brighter?
image intensifier
What is the mA range for fluoroscopy mode? For radiographic mode?
.5 - 5 mA
What is the image intensification?
electronic vacuum tube that converts the remnant x-ray beam to light then to electrons then back to light increasing the light intensity in the process
What do the input phosphor, photocathode, electrostatic focusing lenses and output phosphor do?
Input Phosphor: converts exit radiation to visible light
photocathode: converts visible light to electrons
electrostatic focusing lenses: accelerates electrons towards output phosphor
output phosphor: converts electrons to visible light (brighter image)
What does the Automatic Brightness Control do?
a function in fluoro units that maintains the overall appearance of the image by automatically adjusting the kVp, mA or both
What does magnification mode do? How is it achieved?
many image intensifiers have a mode that increases the size of the area of interest displayed on the monitor .. improves visibility of small anatomic structures .. voltage to the electrostatic focusing le ses is increased .. the focal spot is shifted farther from the output phosphor .. operating In the magnification mode will increase patient exposure
What is vignetting?
decreased brightness at periphery
What are problems that can occur with image intensifiers?
distortion(pincushion) .. vignetting(decreased brightness at periphery) .. noise(quantum mottle)
What is brightness gain? Flux gain? Minification gain?
brightness gain: the product of both flux gain and modification gain; this results in a brighter image on the output phosphor
flux gain: the increase In light intensities at the output phosphor by accelerating the electrons
minification gain: increased light intensities as a result of the reduction in size of the output phosphor image compared with that of the input phosphor image
What is the difference between continuous fluoroscopy and pulsed fluoroscopy?
continuous: x-ray exposure continues without interruption .. increased patient dose .. increased visibility of motion
pulsed: x-ray exposure is not continuous and has gaps of no exposure .. decreased patient dose
Radiation safety. List elements of radiation safety. How can you decrease dose to a patient?
should intermittently pulse x-ray beam .. time distance and shielding .. the intensity of the xr-ray exposure at the table top should not exceed 10 R per minute .. the source to skin distance (SSD) should be no less than 15” (38 cm) for stationary and no less than 12” (30 cm) on a mobile or c-arm
What protective measures could you take to keep yourself safe in a fluoroscopy room.
wear lead apron with 0.5 mm of lead .. increase distance from patient as much as possible .. document total exposure time ..
Digital Fluoroscopy Systems. What did the flat panel detectors replace? What are some advantages?
replaces image intensifier .. 2 forms available (indirect and direct)
Indirect: cesium iodide amorphous silicon .. most common
direct: amorphous selenium