Radiology Lecture Flashcards
What are four reasons taking radiographs are important?
- We can’t see internally.
- They help support a diagnoses.
- They help rule out other causes.
- They help determine a treatment.
Two people can look at the same radiograph and come up with two different diagnoses. What are three reasons for why people may interpret a radiograph differently?
- Quality of the radiograph.
- Patient positioning.
- Blinders phenomenon (When you view one thing on a radiograph and miss another problem)
What is the difference between radiographs and x-rays?
Radiographs are the images we are appreciating while an x-ray is the beams produced by the x-ray machine to make a radiograph.
What is the correlation between x-ray absorption and the density of an object?
The denser the object the more x-rays absorbed (lead, bone, other metals).
X-rays are known to cause damage to cells. What types of cells do they do the most damage to and give four examples.
Fast replicating cells (thyroid, eyes, GI tract, and fetuses).
What five things does one need to produce an x-ray?
- Source of electrons.
- Methods of acceleration.
- Obstacle-free path.
- Vacuum environment.
- Target for interaction
Concerning the cathode portion of an x-ray:
- What is the cathode part of an x-ray?
- What are its filaments made up of?
- What is the correlation between the atomic number (energy) and the number of electrons to give?
- What heats the filaments?
- What does the heated tungsten create?
- What is the current measured in?
- What is the correlation between mA and the number of electrons?
- What directs the electrons to the anode?
- The source of electrons.
- Tungsten.
- High atomic number the more electrons to give.
- Electricity heats tungsten filaments.
- Electron cloud.
- Miliamperage (milliamps or mA)
- The higher the mA the more electrons.
- Focusing cup
Concerning the anode portion of the x-ray machine:
- What is the anode portion of the x-ray machine?
- What is it made of?
- How much energy is released as heat and x-rays?
- How is the anode angled?
- Target area for the electrons (Also called the focal spot and the smaller the spot the sharper the image).
- Tungsten.
- 99% of the energy is released as heat only 1% of the energy is released as x-rays.
- 11-15 degrees downwards towards the patient.
What are two examples of x-ray units with stationary anodes?
- Portable x-ray machines.
- Dental x-ray machines.
What are two disadvantages of stationary anodes?
- Lower heat tolerance.
- Over time exposure to heat pits the anode and causes the x-rays to scatter and is more dangerous.
What x-ray machine contains a rotating anode and why is a rotating anode preferred over a stationary anode?
- Standing x-ray machines that they have in clinics.
- The disks rotates at high speeds which allows the heat to spread evenly and prevents pitting (Pay attention if you do not here rotation then something is wrong and the machine needs to be checked.
Where is the intensity of the x-rays greater?
Cathode side (Usually the right side)?
Since the cathode has a higher concentration of x-rays which part of the patient should be positioned towards the cathode?
The thicker part of the patient (Head and shoulders).
What is the line focus principle?
It is a principle that describes how electrons interact with the anode and change direction.
Concerning the line focus principle what three things occur when the anode is angled 15 degrees or less?
- The beam is narrower and thus produces a higher resolution image.
- There is high heat at the focal spot.
- High levels of x-rays and bloom effect make a larger focal spot.
