Image Production Kettering Audio Flashcards
Define Receptor Exposure:
The overall amount/quantity of x-ray radiation that reaches the IR
The main controlling factor of receptor exposure:
mAs
The relationship between mAs and Receptor Exposure:
Directly Proportional
If you increase the mAs, what happens to receptor exposure?
Increases
Double mAs: __________ Receptor Exposure
Double
Define Contrast:
The difference in adjacent areas
Kvp is the main controlling factor of:
Subject Contrast
The main controlling factor of image contrast:
Look Up Table (LUT)
The relationship between kvp and contrast:
Inversely Proportional
Increase kVp, contrast _______
Decreases
Increase mAs, _______ contrast
No effect
The relationship between SID and Receptor Exposure:
Inversely proportional
Increase SID, _________ receptor exposure
Decrease
Increase SID, _________ Contrast
No effect
The relationship between Receptor Exposure and kVp:
Directly Proportional
Increase in kVp: ________ receptor exposure
Increase
Increase kVp: ______ contrast
Decrease
The relationship between kVp and contrast:
Inversely Proportional
Increase Grid Ratio: ________ Receptor Exposure
Decrease
The relationship between Grids (Grid Ratio) and Receptor Exposure:
Inversely proportional
What do grids do?
Clean up scatter radiation and have the contrast more black and white by appearance (high contrast)
Increase Beam Filtration: what happens to receptor exposure and contrast
Decrease
Define Subject Density:
How tightly compacted at the atomic level
List in order from least to greatest attenuation:
Air Fat Bone Muscle
Air
Fat
Water
Muscle
Bone
List in order from greatest to least attenuation:
Bone
Muscle
Water
Fat
Air
If more radiation reaches the IR, receptor exposure ________
Increase
If more radiation gets absorbed in the patient, _____ contrast
Increase
What kind of kV do you use on a mammogram?
25-30 kV
What would you do with the kV for soft tissue examination of the neck?
Drop it
When things have the same attentuation:
Drop the kV, maximal differential absorption
Responsible for the blacks and whites on an image:
Photoelectric Effect
Why is air dark black on an image?
Shows a high rate of radiation reaching the IR (less attenuation)
Anything white or opaque on an image:
Shows high rates of absorption (high attenuation) low rates of radiation reaching the IR
Increase in subject density, ________ contrast, ________ receptor exposure
Increase, decrease
Additive pathology, ________ receptor exposure, ________ contrast
Decrease, Increase
Destructive pathology, ___________ receptor exposure, __________ contrast
Increase, decrease
Increase beam restriction= _________ field size, ________ receptor exposure, _______ contrast
Smaller, decrease, increase
Increasing collimation (beam restriction) results in:
Decreasing Field Size
Decreasing Receptor Exposure
Decreasing the amount of scatter reaching the IR
Increase Collimation=
Decrease in receptor exposure, decrease in contrast
Increase field size=
Increase in receptor exposure, decrease contrast
Distortion:
Misrepresentation
What affects size distortion?
SID
OID
Shape Distortion:
Foreshortening and Elongation
If you increase SID, what happens to magnification? Recorded Detail (spatial resolution)?
Decreases, Increases
Why do you do a PA Chest Erect at 72 inches?
To reduce heart magnification
Increase OID, magnification? Spatial Resolution?
Increase magnification, decrease spatial resolution
Which had the greatest effect on magnification? SID or OID?
OID
For every 1 inch for OID, increase SID by?
7 inches or 8 inches
Increase SID:
Decrease magnification
Increase OID
Increase Magnification
Two focal spot sizes:
Small and Large
If you increase focal spot size:
Decrease Spatial Resolution
If motion is present on an image:
Compromised spatial resolution
If motion is present on an image:
REPEAT IT
As a technologist you forget the AP Axial Projection of the sacrum, you forget to angle the tube and come in perpendicular, what will the resulting image look like?
Foreshortening (Shape Distortion)
Define Matrix:
Number of rows times the number of columns
More rows and more columns=
Greater pixel coverage
Increase matrix size=
Increase spatial resolution, better pixel coverage
Increase pixel size:
Decrease Spatial Resolution
As PSP plate size increases:
Spatial resolution decreases
The main controlling factor of spatial resolution is:
Sampling Frequency or (focal spot size)
As the field of view increases for a fixed matrix size:
Spatial resolution decreases (increase pixel size)
Increase in the flat panel DEL,
Decrease spatial resolution
Receptor Exposure Define:
Overall amount/quantity of radiation that reaches the IR
Definition of Radiographic Contrast:
Difference in adjacent areas
If an image has high contrast: more/less blacks and whites
MORE
Low contrast:
Lots of shades of grey, less blacks and whites
Seperate mA and time in a question. Multiply in the question and match in the answer.
Law of reciprocity
Define inverse square law:
Intensity is inversely proportional to the square of the distance
If distance gets ever gets doubled or cut in half the intensity will change by a factor of:
4
If you double the distance intensity is:
4 times less
If you cut the distance in half intensity is:
4x more
Direct Square Law Equation:
mAs1/mAs2 = (SID1/SID2)^2
What new mAs will be used to MAINTAIN:
Direct square law/receptor maintenance formula
The 15% kVp rule states:
If you increase or decrease the kVp by 15% you either double or cut the receptor exposure in half
Double the receptor exposure by applying the 15% kVp Rule, at 80 kVp and 30 mAs, what is the new technique?
92 kVp and 30 mAs!
Cut the receptor exposure in half by applying the 15% rule, 80 kVp and 30 mAs. What is the new technique?
68 kVp and 30 mAs
“The receptor exposure is sufficient, but the contrast needs to be increased”
Use the 15% kVp rule. Increase kVp. Cut the mAs in half on the backend. Decrease kVp, double the mAs
Grid Ratio=
H/D
In a diagram, height of the lead strips (use), thickness of lead strip (not use), distance between the interspace (use):
H/D
Non-Grid:
1
5:1 Grid:
2
6:1 Grid:
3
8:1 Grid:
4
10:1/12:1 Grid:
5
16:1 Grid Ratio:
6
A Radiographic examination is performed 80 kV, 10 mAs, 100 cm SID, with a 5:1 Grid Ratio. A new exposure is made with a 16:1 Grid Ratio to increase the contrast. What is the new technique?
Old mAs/new mAs= Old Grid/new Grid
A Radiographic examination is performed with 70 kV, 10 mAs, 100 cm SID, with a 200 speed image receptor, a new exposure is made with a 8:1 grid. What is the new technique?
Apply the non grid=1
Have to go with the closest number to the calculator. Old mAs/New mAs = old grid/new grid
The purpose of filtration:
Cleans up longer wavelength x-rays, soft x rays, reduces the ESE
As part thickness increases:
Increase in attenuation
Attenuation
Reduction in x-ray intensity that passed through matter
As atomic number increases:
Attenuation increases
Define pathology:
Define Atalacticis:
Collapsed lung
Define Ascities:
Accumulation of Fluid
Define pneumothorax:
Define spondolotithesus:
Displacement of one vertebra on top of another vertebra
Additive pathology: what happens to technique?
Increase technique
Destructive pathology; what happens to technique?
Decrease technique
A patient presents in the ED department fever shortness of breath, cough:
Pneumonia (pneumonic infiltrate)
The patient presents with diapheretic, cool clammy to the touch, fever:
Congestive heart failure
So T-spine, place the cathode over: and the anode:
Lower t-spine, upper t-spine
Always place the cathode over the:
Proximal joint
Always place the cathode:
On the thoracic and abdominal cavities
The cathode goes:
Lower t-spine, lower thorax, lower diaphragm
On a average adult, lateral T-Spine it requires: 3 views Ap Lateral the lateral cervical thoracic projection (Swimmers).
Put the cathode up
Short scale contrast:
Black and white appearance
I’m a myeologram we inject intrathecally:
Within the spinal canal
The three things that effect the production of scatter radiaiton
High kVp
large thick parts
large field sizes
All of the following effect the production of scatter radiation except:
The use of a Grid
Long scale:
More gray appearance
Increase kVp
Decrease contrast (forward scatter)
What controls image contrast on a chest x-ray?
LUT
Computers algorithm
Histogram analysis
With the use of filtration the beam becomes:
More homogenous
Umbra
Clear concise center
Penumbra
Blurring around the edges
The penumbra (geometric unsharpness) is always greater on the:
Cathode side of the beam
If you increase the OID:
Increase magnification, decrease spatial resolution
A heart on an IR measures 15.2 cm at its widest point but its true width in the chest cavity is 13.6 cm. How much magnification?
Image size/object size, always bigger on the image (big/small)
A Radiographic examination is performed with 180 cm SID, but the anatomical part has a 20cm OID. How much magnification?
SID/OID
SID-OID=SOD
180-20= 160
180/160= 1.125
When the day how much magnification: use what formula
SID/SOD
Increase SID:
Decrease magnification, increase Spatial resolution
What effects size distortion and spatial resolution:
OID and SID
What is the best way to control voluntary motion? Respiration, peristalsis, Parkinson’s disease
Clear concise instruction
Proper communication
What is the best way to control involuntary motion:
Shortest possible exposure time
Increase in focal spot size:
Decrease in spatial resolution
Sampling frequency controls:
Spatial Resolution
Define Actual Focal Spot:
Electrons actually strike the target
Define effective focal spot:
Gets projected down to the patients
Which is larger the actual or effective focal spot?
Actual
The incorporated design of the line focal principle creates:
Larger actual focal spot
smaller effective focal spot
Which of the following anode angles gives you the greatest spatial resolution:
Pick the smallest angle!
If you are doing a hand X-ray and doing it table top, is it the use of APR or AEC?
APR (anatomically programmed radiography)
Caliper:
Device used to measure part thickness.
Fixed kVp
kV stays fixed for the exam.
60 kv on every hand, 70 kv on every knee, 80 kV on every pelvis but it is appropriately fixed for that examination.
kVp is determined by using ______ to accurately measure the thickness of the body part being evaluated
Caliper
Variable kVp
Always use 10 mAs on every knee, 20 mAs on every hip, 30 mAs on every pelvis. The kVp changes.
A set of calipers an anatomical part (pelvis) to be 20cm, 21 cm, 22cm you would use how much kV?
80 kV, 82 kv, 84 kv
For every cm of part thickness increase, increase ____ kVp per.
2
A patient falls hurts their wrist, plaster cast on wrist, what new kVp?
8-10 kVp increase
2 months later the patient is going to see if they can take the cast off, it is perfectly drive how much kVp increase?
5-7 kVp increase
Fiber glass cast is a how much kVp increase?
3-4 kVp increase
Anytime an anatomical part exceeds how many cm you need to get a grid:
10 cm rule
What cell would you select for a PA projection of chest?
The two outer cells
What cell would you select for the axial skeleton? (Skull to coccyx)
Center Cell
The ala of the pelvis (wings of the pelvis) what cell would you select?
Outer Cells
Pelvis and concentrate on Sacrum or Coccyx what cell would you select?
Center cell
Abdomen with a concentration of the spine what cell would you select?
Center Cell
Abdomen with a concentration of the kidneys, what cell would you select?
Outer cells
what is the main/single most disadvantage when using the AEC device?
Inaccurate or inadequate or improper positioning
Spatial resolution definition:
The ability of the system to record small adjacent structures. The sharpness of the structural edges recorded in an image.
What is spatial resolution measured in?
Line pairs per mm (lp/mm)
Define pixel:
Picture element
Smallest area depicted in an image
Two-dimensional square that contains discrete gray shades
Define Pixel size:
Measurement from one end to the other end
As pixel size increase, ________ spatial resolution.
Decrease
Pixel pitch define:
Measured from center to center.
As pixel pitch increases, ________ spatial resolution
Decreases
Pixel Density:
Number of pixels per millimeter
Determined by the pixel size and pixel pitch.
As pixel size decreases, pixel density _______.
Increases
Matrix:
Number of rows times the number of columns
An increase in matrix size:
Greater spatial resolution
Smaller matrix size, larger pixel:
Spatial resolution decreases
Bigger matrix size, smaller pixel:
Increase spatial resolution
Define sampling frequency:
The number of pixels sampled per millimeter as the laser scans each line of the imaging plate.
The main controlling factor of sampling frequency is:
Spatial resolution
A CR cassette, the PSP plate gets withdrawn, and it runs underneath, the laser scans the imaging plate the more pixels it reads:
The greater the spatial resolution
Increasing sampling frequency=
Increase spatial resolution
Nyquist Frequency definition:
The relationship between sampling frequency (number of pixels/mm scanned by the laser at a rate that is 2xs highest frequency present) and the spatial resolution (resulting image detail)
As the DEL increases, _________ spatial resolution
Decreases
When we do extremities such as carpals and tarsals we want what size DEL?
Small
The relationship between DEL and spatial resolution:
Inversely Proportional
Dynamic range:
Range of acceptability
Quantum mottle definition:
An insufficient quantity of x-rays to reach the IR
The main controlling factor of Quantum mottle:
mAs
Signal to Noise Ratio Definition:
Ratio between signal or meaningful information and noise or background information
Which of the following SNRs gives the greatest spatial resolution?
2:1
4:1
8:1
16:1
16:1
(16 signal/contrast to 1 noise)
Who owns the image?
The institution maintains ownership
All of the following are mandated on the image to make the document legal and binding in the court of law except:
DOB
POST EXPOSURE MARKER
PATIENT AGE
Every complement of the x-ray tube is internal except:
Stators
What charge is the cathode:
Negative charge
Glass envelope function:
Helps protect the internal components of the x-ray tube
Maintains a vacuum environment within the radiographic tube
What is the glass envelope material:
Pyrex glass
What charge is the cathode?
Negative electrode
What components make up the cathode?
Filament Wires
Focusing Cup
What material is the focusing cup?
Molybdenum or Nickle
What material is the filament wires?
Thoriated Tungsten
The focusing cup functions to:
Maintain a predetermined number of electrons around the filament prior to exposure
The focal spot (where the size of the focalpot direct toward the image receptor) is smaller/larger than the focal spot measured on the surface of the anode:
Smaller
What does the focusing cup do?
Operates at a saturation current- maximum current level at a given tube current
Which part of the x-ray tube is outside of the vacuum tube?
Stator
Leakage radiation should not exceed:
100 mR/hra in air at 1 meter
Why is the actual focal spot larger than the effective focal spot?
Line focus Principle (the anode is angled)
The flow of electrons:
Always negative to positive
Cathode to anode
One way flow
Anode material:
Tungsten Target with Rhenium
Materials or choice of materials for the neck and the base of the anode:
Copper, molybdenum, graphite
Because they provide weight savings if the anode assembly
The induction motor:
Two components make up the induction motor: Rotor and stator
The name of the motor that drives or powers the anode during exposure
Isotropically:
Equal intensities in all directions
A properly designed lead lines protective housing will reduce the leakage radiation to:
1 mGya per hour at 1 meter
100 Mr/hra at 1 meter
Three chest x-rays, 8 year old, 80 year old female hypodermic and ammonia and a 40 year old hyperstenic:
Photo time all of them (AEC)
What is the purpose of using a back up timer when using an AEC device?
Patient safety device in case of equipment malfunction
Minimum Response Time (MRT) definition:
The time it takes for a system to respond and sends signal to terminate the exposure
PBL:
Positive beam limitation device
Automatic collimation
The use of beam restriction does the following:
Decrease Dose, Decrease Receptor Exposure, Increase Contrast
Aperture Diagram:
Simplest type of beam restricting device, a lead plate with a hole cut in the middle that is slightly smaller than the image receptor size
Variable Aperture Collimation:
Controlled by the radiographer
Permits the adjustment of the length and width of the radiation light field
Utilizes a light localization device to estimate the size and shape of the radiation field
Cylinders or Cones:
Attaches to the bottom of the collimation housing
Creates a circular shaped collimation field
Maximum beam restriction occurs with increased length and decreased diameter of the cylinder or cone
How does collimation affect patient dose, receptor exposure, contrast?
Patient dose decreases, receptor exposure decreases, contrast increases
Use of any beam restriction device:
Patient dose decreases, contrast increases
Ohm’s Law definition:
V= IR
V measures=
Voltage or electric potential
I measures=
Amperes
R measures=
Resistance measured in Ohms
If you have a 100 mA station, 25 m/s what is the mAs?
0.025 seconds
A parallel circuit had 4 resistor elements of 5, 10, 20 ohms. What is the total resistance?
3.43 ohms approximately
A series circuit has 4 resistant elements of 5, 10, 15, 20 ohms. What is the total resistance?
50 ohms
Where can you find the auto transformer?
Primary/Low Voltage Side
Where can you find the exposure timer?
Primary/Low Voltage Side
Where can you find the x-ray tube?
High Voltage/Secondary
Where can you find the mA selector?
Filament
Where can you find the focal spot selector?
Filament
Where can you find the step down transformer?
Filament transformer
The electrical energy supplied to the x-ray unit is:
Alternating Current (AC)
Any induction self/mutual requires what current?
AC current
Source of EMF/electric potential:
Voltage
The focusing cup is positioned around the:
Filament wires
Electric potential is the unit of the:
Volt
Auto transformer
Single coil of winding
Works on the principle of self induction
Determines the amount of line voltage that will be sent to the step up transformer
All induction requires what current:
A/C
Which of the following transformers is considered the most efficient?
Shell Core
A transformer has 10,000 turns on its secondary side and 500 turns on its primary. What is the turns ratio for this transformer?
TS/TP
10,000/500
20:1
20 secondary to every 1 primary
A transformer has 5000 turns on its primary side and 100 turns on its secondary side. What is the turns ratio for this transformer?
100/5000= 1:15 (1/50)
Secondary divided by primary only.
A transformer has a turns ratio of 200:1. If 150 volts are supplied to the transformer, what is the output voltage?
Always supply the primary coil
Vs (x)/ 150
200/1
Vs/VP = TS/TP
200 (150); x= 30,000 volts or 30 kV
Where is the auto transformer located?
The primary or low voltage circuit between the incoming line voltage and the primary side of the step-up transformer.
What is the source for kVp?
Auto transformer.
Where is the line voltage compensator located?
Located within the primary or low voltage circuit of the x-ray unit and connected to the primary side of the auto transformer
What does the line voltage compensator do?
Maintains a constant voltage/turns ratio within the auto transformer
What is the step up transformer also known as?
High voltage or high tension transformer
What does the step up transformer operate on the priniciple of?
Electromagnetic mutual induction (two wires)
Where or when does voltage become kilovoltage?
Step up transformer
Secondary side or output side of the step up transformer
Filament transformer is also known as:
Low voltage or step down transformer
Where is the filament transformer located?
Low voltage filament circuit
The step up transformer gives the desired _______ the step down delivers the ________ _______.
Voltage, Thermionic Effect
The filament transformer works off of the principle of:
Electromagnetic mutual induction (two wires)
Current is ______ to the transformers turns ratio
Inversely proportional. This means that the current will be reduced by a step up transformer and increased by a step down transformer.
An mA station is considered to be a:
Variable resistor
The pre-reading kVp meter reads:
Voltage
Where is the pre-reading kVp meter located?
Low voltage side
All of the following are examples of exposure timers except:
mAs
Electronic
Synchronous
Recipricating
Answer: recipricating
Which of the following timer devices is considered the most accurate?
Electronic Timing Devices
What is the main controlling factor of spatial resolution?
Sampling frequency/Focal Spot Selector
Two types of focal spot sizes:
Small and Large
Use a small focal spot on:
Carpals and Tarsals (things that require a lot of detail)
The main advantage of the small focal spot is:
Greater spatial resolution
Greater Recorded Detail
The disadvantage of the small focal spot size is:
Can not withstand the heat
The large focal spot advantage:
Can withstand high speed electrons bombarding it
The disadvantage of the large focal spot size:
Does not give good spatial resolution or recorded detail
Which is larger the actual focal spot size or effective focal spot size?
Actual
In the United States, electrical energy is supplied in a __________ cycle alternating current
60 second
1000:1
Goes back and forth 60 times in one direction
Cathode anode and exits down to the patient
What does rectification do?
Converts AC to DC
Single Half wave rectified voltage ripple and how many useful pulse per second?
100%
60/sec
Single Full Wave Rectified voltage ripple and how many pulse/sec?
100%
120/sec
3 phase Six Pluse voltage ripple and how many useful pulse/sec:
13%
360/sec
3 phase 12 pulse voltage ripple and how many useful pulse/sec?
4%
720/sec
High frequency voltage ripple:
Less than 1%
Image Intensifier:
To increase overall brightness
To convert x-ray beam into a bright visible light
X-rays with interact with the input phosphor and gets converted to:
Light
What does the photocathode do?
Converts light photons from the input phosphor into free electrons
Anode in Flouroscopy Unit:
Metal plate with a hole in the middle
XLELM
X-rays to light, light to electrons, electrons back to light, and to the monitor
What material makes up the input phosphor?
Cesium Iodide
What does the photocathode do?
Converts light photons from the input phosphor into free electrons
What does the electrostatic lens do?
Directs or focuses the path of electrons from the photocathode to the surface of the output phosphor screen
What does the output phosphor do?
Converts electrons sent from the photocathode into light photons.
What is the material of the output phosphor?
Zinc cadmium sulfide
Define Brightness Gain:
Minification Gain times Flux Gain.
BG= minification x flux
Define minification:
The diameter of the input squared Divided by the diameter of the output squared
An image intensification tube with an input phosphor size of 17 cm and an output phosphor size of 2.5 cm with a flux gain of 100. What is the brightness gain?
Minification gain= 17^2/2.5^2, Minification gain = 46 x 100 = 4600 lumens brighter with an image intensifier vs without
Which one controls the bright light vision (photopic)?
Cone of the eye
Which controls Low light or night vision (scotopic)?
Rods of the eyes
Define vignetting:
Loss of detail and fall off of brightness along the edge of the fluoroscopic image
Loss of resolution around the periphery? (Fluoro)
Vignetting
Loss of resolution around the periphery of the image?
Vignetting (looks like a pin cushion)
Which of the following recording devices gives the highest patient dose?
Cine fluoroscopy
Recording
10xs the next competitor
When you are in fluoroscopy and you move from a thicker part to a thinner part you do not have to move and adjust the technique:
The machine will adjust the increase/decrease kVp and mAs through the ABC or AERC device.
When magnification takes place in flouroscopy, _________ patient dose.
Increase
Anterior surface of the foot is called:
Dorsum (dorsal) Surface
In the mag mode in flouroscopy _________ spatial resolution and _______ contrast resolution
Improve both
The disadvantage of magnification mode is:
Increase patient dose
Flouroscopy is the greatest source of:
Acute radiation exposure to the patient in the diagnostic radiology environment
Cr is a cassette based system what are the types:
- (PSP) Photostimulable phospher plate
- Flat panel detector/thin film transistor (FPD/TFT)
- PSP plate with a charged couple device (CCD)
What is the imaging plate used in a CR Cassete?
PSP (photostimuable phospher)
What are the PSP materials made of?
Europium activated barium flourohalide
Phospher or Active Layer Definition:
Contains the photostimuable phospher that traps electrons during the Radiographic exposure
Latent
Invisible
Manifest
Visible
Manifest
Turning an latent image into a visible image
A technologist is using a CR cassette operating off of a PSP system x rays blow through the anatomy of interest and you get a disruption of valance band electrons: what do you do?
Latent image exists
Place the cassette on the workstation
Imaging plate is removed by the cassette
Gets scanned by the laser
Electrons that got distrusted that are trapped
Voiolet light releases them
The S system has a ______ relationship
Inverse
If the range of acceptability is 200-400, as an operator your goal is to be:
Directly in the middle of the range
If the exposure range is 200-400 and your S value is 125. What does this mean?
Over exposed the patient
If the exposure range is 200-400 and your S value is 450. What does this mean?
Underexposed
EI and the Lgm are ________ proportional
Directly
DR is:
Casetteless
The DR cassette less system consists of:
1) FPD/TFT
2) CCD
3) CMOS (complimentary metal oxide semiconductor)
4) PSP Plate with a CCD
Indirect DR:
3 step process, scintillator based uses cesium iodide or gadolinium oxysulfide
Direct DR:
Non-scintillator based systems does not use a material that converts x-rays to light
What is the name of the device used to convert x-ray photons into light?
Schintillator
Scintillator based systems use:
Cesium iodide (CSI) or gadolinium oxysulfide
Direct DR material:
Amorphous selenium (a-Se)
What are the materials used in indirect capture?
Cesium Iodide (Csi) or gadolinium
Amorphous silicon (a-Si)
What are the materials used in direct capture?
Amorphous selenium (a-Se)
ADC stands for:
Analog to digital converter
What is the main controlling factor of contrast:
LUT (look up table)
Equalization definition:
Method of image processing using the histogram of the image to adjust contrast. Allows for the demonstration of a wide range of anatomical structures without overall loss of image quality
What does equalization improve?
Display range
Interventional radiology DVT anuerysm, Evaluate flow in the vessels. Why do you want the bone in the way?
You don’t. You want to make it or through the process of subtraction you have masking
Leg length, scoliosis series question:
Stitch!!
Stitch images together to combine multiple images for anatomy that is too large for a single exposure, resulting in a seamless image
Shuttering definition:
Removes or replaces the background information
Which of the following matrix sizes will give you the greatest spatial resolution
1020 x 780
1919 x 708
the biggest number is the answer
Define Hounsfield Unit/CT number:
Each pixel is given a numerical value based on the receptor exposure in the pixel
FOV definition:
The diameter of image reconstruction
Voxel (volume element) definition:
Volume of tissue imaged is given a value
Window level allows you to adjust the:
Brightness
Window width allows you to adjust:
Image contrast
A narrow width:
Short scale appearance
White and black
A wide window width:
More shades of grays
Long scale of contrast
DICOM stands for:
Digital imaging and communication in medicine
Exchanging images is done by the process of:
DICOM
PACS stands for:
Picture archiving and communication system
PACS definition:
Consists of digital acquisition equipment, workstations for display, and manipulation of images and interconnected storage devices that communicate in the same language of DICOM
Definition of teleradiology:
Process of remote transmission and viewing of images
HIS:
Hospital Information System
Contains full patient information
RIS
Radiology Information System
Contains radiology specific information about the patient including the radiologists report (modality work list)
EMR:
Electronic medical record
EHR:
Electronic health record
What is the minimum change to show a perceptible difference?
Minimum of 30%
PSP plate can only be cleaned with:
Anhydrous ethanol
Outside of the CR cassette can be cleaned with:
ANY disinfectant
Light field of radiation field alignment QC:
Plus or minus 2% of the source to image distance
PBL must be within:
2% of the SID
SID indicator must be within:
+/- 2%
CR must be within:
1.25 cm (0.5 inches) of the indicator
Linearity:
+/- 10%
Filtered beam in mgy must be at least:
50% of the unfiltered beam
Beam must be within ______ degree of perpendicular
1 degree
Exposure timer QC:
+/- 5%
kVp QC:
+/- 5%
QCs should be performed:
Daily for technologist
Imaging plates that have been unexposed for longer than ________ should be erased.
24 hours
Which of the following will increase spatial resolution?
Increase SID
Decrease FOV
Decrease OID
Which of the following is inversely proportional to IR exposure?
SID
Grid Ratio
Filtration
