Exam (elaborations)
Irene Gold PART 2 Supplemental: XRAY – Qs & As
- Course
- IRENE GOLD
- Institution
- IRENE GOLD
Irene Gold PART 2 Supplemental: XRAY – Qs & As
[Show more]
Content preview
Irene Gold PART 2 Supplemental: XRAY – Qs & AsWhat am I?
•Fast moving electrons collide with matter in any form, xrays are produced
•In an x ray tube this is done by directing a stream of electrons at a high speed
against a metal target
•As they interact with the atoms of the target, the electrons give up most of
their energy in the form of heat
•However about 1% of their energy is emitted as x radiation
•The X-ray tube is inside a heavily lead lined protective housing.
•The x ray tube is located within a glass envelope (Pyrex inside the tube
housing.
•The tube consists of 2 electrons called the cathode and anode ✔️Ans -
Production of X rays
What does a Cathode consists of? ✔️Ans - • Large filament
• a small filament
• focusing cup
What am I?
• Serve as the source of electrons in the production of x rays and are made of
tungsten
• Thermionic emission occurs when a current is applied to the filament, the
coil of the wire becomes very hot, boiling off electrons
• The temperature of the filament controls the quantity to electrons (mA)
emitted from it.
• The number of electrons determines the number of x rays created ✔️Ans
- The filaments (X-ray)
What am I?
• Part of the cathode and encases the 2 filaments.
• This is where thermionic emission occurs ✔️Ans - Focusing
cup/filament cup
What am I?
• Positive electrode in the x ray tube
• Most x ray tubes consist of a rotating anode
,• Rotating target receives electrons as they move from cathode to anode
✔️Ans - Anode
What am I?
• The reason for the rotating target is to dissipate the heat generated
• This exposes an area of the tungsten target of the anode and this area is
called the focal spot
• Focal spot will be determined by the size. Of filaments that is chose
• Smaller filament=better detail ✔️Ans - The rotating anode target
What am I?
• Has the effect of making the actual focal spot size appear smaller when view
from the position on the film
• The smaller the target angle, the smaller the effective spot.
• Stream of electrons narrows down to an effective beam ✔️Ans - The line
focus principle
What am I?
• Heats the filament causing a boing off of electrons ✔️Ans -
Milliamperage (mA)
What am I?
• More current=more electrons produced=more extras produced=greater
radiograph density (darker) ✔️Ans - Milliamperage per second (mAs)
What am I?
• The overall blackening on a film
• Radiolucent: structures that produce more blackening on the film
• Radiopaque: structures that produce less blackening on the film (whiter)
✔️Ans - Density
What am I?
• The relationship is directly proportional
• Changing the mAs is the primary method to control the blackening on the
film
• MAs increases= more film exposure
, • It takes a minimum change of 30% to see a minimum change in density on
film
• If the mAs is doubled the density is doubled. If the mAs is halved the density
is halved ✔️Ans - MAS and density
What am I?
• Force applied to accelerate the electrons front the cathode to the anode at
the time of exposure
• The greater the force, the greater the numbers of high energy x ray photons
will produced
• Wavelength and frequency are inversely related
• Low kVp=low energy=weak penetration
• Higher kVp produces shorter wavelengths with a greater ability to penetrate
tissue ✔️Ans - Kilovoltage (kVp)
What am I?
• The difference in density between 2 structures
• Contrast makes detail visible
• KVp controls contrast but they are inversely related ✔️Ans - Contrast
What am I?
• High contrast=short scale
• Type of film will have sharp difference in dark and light areas. A black and
white film=underexposed (bone film)
• Low kVp produces less scatter, however the amount of radiation absorbed
by pt is increased ✔️Ans - Low kVp
What am I?
• Low contrast=long scale
• Type of film shows very little differences between densities
• More shades of grey (soft tissue film)
• High kVp produces more scatter, however the amount of radiation absorbed
by the patient is decreased ✔️Ans - High kVP
What am I?
• To lower contrast-longer scale of contrast- more shades of gray you must:
increase kVp by 15% and decrease mAs by 50%
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller LeCrae. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for CA$25.18. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
67096 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now