Flashcards in X-Ray Physics (Part II) (Irene Gold) Deck (135):
What three things are found inside the Cathode?
What is the source of the electrons that produce the x-ray?
What is the filament made out of?
When does a Thermionic Emission happen?
When current is applied to a filament
What controls the quantity of electrons (mA)?
Temperature of the filament
What part of the cathode encases the two filaments?
In what part of the Cathode does the Thermionic Emission occur?
What is the name of the positive electrode in the x-ray tube?
In most x-ray machines is the anode stationary or rotating?
What is the reason for a rotating Anode target?
To dissipate the heat that is generated
What is the focal area/spot of the Anode?
The exposed area of the tungsten target
How is the focal spot determined?
By the size of the filament
What does a Smaller filament produce as an outcome?
What is it called when "The effect of making the actual focal spot size appear smaller when viewed for the position on the film"?
Line Focus Principle
What give you a smaller effective spot on x-ray?
Smaller target angle
What is the term used that "Heats the filament causing a boiling off of electrons"?
How is the term Millamperage per Second defined (mAs)?
More Current=More Electrons produced= More x-ray produced= Greater Radiographic density (Darker)
What is the term used for overall blackening on the film?
What does the term Radiolucent mean?
Structures produce more blackening on the film
What term is used for "Structures that produce less blackening on the film"?
(Whiter on X-ray)
The relationship between what two components of x-ray mAs and density?
They are directly proportional
What is the primary way to control how black a film is?
If the mAs is increased what does that mean in terms of film exposure?
The film exposure time is increased
What is the minimum change in mAs to see a change in density on the film?
What does it mean to the density if the mAs is either doubled or halved?
The density will be doubled or halved, they are directionally proportional
What is the definition of Kilovoltage (kVp)?
The force applied to accelerate the electrons from the cathode to the anode at the time of exposure
When will the greatest number of high energy x-ray photons be produced?
When a great force of Kilovoltage (kVp) is produced
What is the relationship between wavelength and frequency?
If there is a low kVp what kind of energy and penetration are produced?
What kind of kVp would produce a high energy and a strong penetration?
What kind of kVp produces shorter wavelengths with a greater ability to penetrate body tissue?
What is the term that "is the difference in density between two structures"?
What is the purpose of Contrast on an x-ray?
Makes detail visible
What is the relationship between kVp and contrast?
Does mAs or kVp control contrast?
In terms of Low kVp; what kind of contrast and scale are produced?
High Contrast=Short Scale
What kind of x-ray will be produced from a Low kVp setting?
Sharp difference in dark and light areas
A black and white film= underexposed (Bone Film)
Low kVp has what two effects?
Produces more scatter
Increased amount of radiation is absorbed by the patient
Low Contrast=Long Scale is seen in what kind of kVp film?
What is expected to be seen on an x-ray film of High kVp?
Very little differences between densities
More shades of grey (Soft Tissue Film)
High kVp films have what two effects?
More scatter produced
Decreased amount of radiation is absorbed by the patient
How can you do the following on an x-ray film:
Longer Scale of Contrast
More Shades of Gray
Increase kVp by 15%
Decrease mAs by 50%
How can you do the following on an x-ray film:
Shorter Scale of Contrast
Fewer shades of Grey (More Black and White)
Decrease kVp by 15%
Increase mAs by 100%
What is the primary way to control density on an x-ray?
What is the relationship between kVp and density?
What is the 15% Rule?
Increase the kVp by 15%=Double the film density
Decrease the kVp by 15%= Half the film density
Which tissue absorbs more x-ray?
What two things are Black on x-ray?
What three things appear Gray on x-ray?
What two things will show up as white on x-ray?
On which side of the x-ray is the intensity the greatest?
Towards what side do you place the thinner portion of the patient being x-rayed?
Anode Side (Anode Heel Effect)
Why is the thinner portion of the patient placed on the Anode Side of the x-ray tube?
Density and Intensity are Decreased
Which Side of the X-Ray machine produces less X-Ray?
What is the size of the Effective focal spot on the Anode Side of the X-Ray machine?
What size of the X-Ray machine produces more Detail?
Where is the Anode side of the X-Ray machine placed?
Used on the thinner body part
On the Cathode side of the X-Ray machine:
Is there more or less X-Ray?
Effective focal spot, larger or smaller?
How much detail is produced, Less or More? Where do you place the Cathode on a patient during an X-Ray?
Focal Spot: Larger
Use on the thicker body part
What term is used to determine "The length of space from the focal spot (tube) to the recording medium (film)?
Focal Film Distance (FFD)/Source Image Distance (SID)
What happens as you increase the Focal Film Distance (FFD)?
The image gets smaller and clearer
What two things happen when you decrease the Focal Film Distance (FFD)?
The image gets:
What law explains how the intensity of the x-Ray beam is affected by the changes in the Source Imaging Distance?
Inverse Square Law
What varies inversely with the square of the distance from the source?
Intensity of Radiation
What happens if a 40 inch Focal Film Distance is doubled to 80 inches of Focal Film Distance?
The intensity at 80 inches of Focal Film Distance is 1/4 the intensity at 40 inches of Focal Film Distance, if no other factors are changed
What must happen to the mAs at 80 inches of Focal Film Distance?
It must be increased 4x the amount from 40 inches of Focal Film Distance, to maintain the same amount of Blackening
What kind of crystals are found in the Intensifying Screen for X-Ray?
What are three findings with large crystals in the X-Ray screen?
Yield Less Detail
What is the "equation" of Large crystals in the X-Ray screen?
Faster Screen=Higher Contrast=Short Scale (Less Patient Exposure)
What part of the X-Ray is intensified using screens?
What is the term used for "Clarity and Sharpness of a Film"?
What does the term Umbra mean?
Picture made by a useful beam
What term is "blurry halo part of the image"?
What three things can cause Penumbra?
Tube to close to the film (Short Focal Film Distance (FFD))
Patient to far from the film (Long Object Film Distance (OFD))
To large of a filament on the Cathode, making the focal spot to big
What is the term used for describing the distance between the patient and the film?
Object Film Distance (OFD)
What happens as you increase the Object Film Distance (OFD)?
Image has more Penumbra; becomes bigger and blurrier
What happens as you decrease the Object Film Distance (OFD)?
Image has better detail; becomes smaller and clearer
How do you get the best detail?
Place the patient as close to the film as possible
What is the term for the following definition: "Pressure exerted by the film holder as it encloses the X-Ray film"?
What is the outcome of poor screen-film contact?
Reduces the sharpness of the image
What are the two types of distortion that can happen on and X-Ray?
What two things are distortion of an X-Ray effected by?
Object Film Distance (OFD)
Focal Film Distance (FFD)
What three things happen when an X-Ray strikes an object?
What four ways can Scatter Radiation be reduced?
Air gap technique
Where is the grid placed?
Between the patient and the film
What is the sole purpose of the grid?
Improve the quality of the radiograph by absorbing scatter radiation
When using a grid, why must exposure factors be increased?
To maintain density
Does the use of a grid increase or decrease the patient's dose of radiation?
What is a Grid Ratio?
The height of lead strips to the distance of Lead strips
What Grid Ratio is used in Chiropractic offices?
What is the definition of the "Air Gap Technique"?
6-10 inch gap between the patient and the film
What happens to the X-Ray as there is an increase in the Air Gap Technique?
Scatter radiation diverges away from the film
Is the patient's radiation dose increased or decreased when there is an Air-Gap?
Decrease, but can distort or magnify the image
What is the main function of Collimation?
Limits the size of the beam to the body part being X-rayed
What is the best way to reduce scatter radiation to both the patient and the film?
What are X-Ray filters made out of?
What is the preferred way to remove low energy photons from an X-Ray?
What function does the filter play during X-Ray?
Stops weak photons (those not capable of getting all the way to the screen) from entering the patient's body, thus protecting from scatter radiation
What is the term used to "Measure the radiation energy absorbed"?
Radiation Absorbed Dose (RAD)
What is the term defined as "Biological effectiveness of the radiation absorbed"?
Radiation Equivalent Man (REM), Badges worn by Radiology Technicians
What is the safe number of Radiation Equivalent Man (REM) per year?
What is the term for "The number of Radiation Equivalent Man (REM) a person can get in a lifetime without getting radiation poisoning"?
Maximum Permissible Dose (MPD)
What is the Maximum Permissible Dose (MPD)?
Maximum Permissible Dose= 5(Age-18)
What is the name of the majority of the useful beam of an X-Ray?
What is the Characteristic of Bremsstrahlung Radiation?
High intensity electron hits an inner shell electron, which is knocked out of it's position in orbit. An out shell electron then fills it's spot
What is the primary form of scatter radiation?
What are two other names for Classic Scatter?
What type of Scatter is "A low energy X-Ray that changes direction with no energy loss"?
How is Compton Scatter described?
A moderate energy X-Ray knows out an outcry shell electron, which causes loss of energy
What type of Scatter contributes to Film Fog?
What is it called when "A low energy photon is absorbed by the subject creating a latent image on the film"?
What is another name for Quantum Mottling?
What type of screen produce the most Mottling?
What two exposure factors will decrease Radiographic Noise?
When processing a film what will increase the density?
Solution temperatures that are to hot
What is the effect of film density if the solutions are to low when the film is being processed?
Density will be low/insufficient
What are the four factors of processing an X-Ray?
What factor of X-Ray processing "Brings out the latent image by exposing the Silver Halide crystals?
What is the purpose of the Rinse step in processing an X-Ray?
Removes the exposed Silver Halide crystals
What step of the making an X-Ray "Hardens the image, making it permanent on the film"?
What step in making an X-Ray removes the Developer and Fixer?
What three things are indicated by Dark Films?
Developer Temperature too hot
What two things does a Light Film indicate?
Developer temperatures are to low
Chemicals need to be changed/replaced
If the Developer is inadequate what color will the film be?
Milky Films indicated an inadequacy in what factor or the x-Ray processing?
If a film is inadequately Washed how will it appear?
What three things can cause an increase in Film Fog?
What does a Soft Emulsion on a film indicate?
How should film/cassettes be stored?
Vertically to avoid pressure damage
What causes creases on an X-Ray film?
What two colors can be added to the base of an X-Ray film to reduce glare?
What is the term when a "beam of radiation loses energy as it passes thru matter"?
What is the definition of Transducer?
One form of energy to another
What term is described as a "step up or step down in power"?
What part of the X-Ray Machine changes Alternating Current (AC) to Direct Current (DC)?