Quiz (self-made) about choice of imaging modalities Flashcards
Which is the most common form of medical imaging, using high-energy radiation to penetrate skin and tissues but not bone?
? Positron Emission Tomography (PET)
? Ultrasound
? X-ray
? Magnetic Resonance Imaging (MRI)
X-ray
Why does bone appear white on X-rays?
? X-rays are absorbed by bone
? X-rays cause a chemical reaction in bone that makes it glow white
? X-rays excite the atoms in bone so that they glow white
? X-rays are reflected off bone
X-rays are absorbed by bone
Which of these imaging techniques use X-rays?
A) Radiography
B) Fluoroscopy
C) Radiotherapy
D) Ultrasound
E) Computed Tomography (CT)
F) Magnetic Resonance Imaging (MRI)
G) Positron Emission Tomography (PET)
? A, B, C, and E
? C, E and F
? All seven techniques use X-rays
? D, F and G
A, B, C and E
Magnetic Resonance Imaging (MRI) is a medical imaging technique most commonly used in radiology to visualize the internal structure and function of the body. Which of these statements about MRI indicates a drawback of this technology?
? MRI imaging machines can cost between 1 and 3 million dollars and the suites required to house the machines cost up to $500,000 each
? MRI technology can be used to observe changes in brain activity in living time
? MRI is very safe for the patient because it does not use any radiation
? MRI can produce multiple two-dimensional images of body structures and three-dimensional reconstructions of them
MRI imaging machines can cost between 1 and 3 million dollars and the suites required to house the machines cost up to $500,000 each.
Fill in the blank.
The darker areas on a plain radiograph indicate that the x-ray beam has passed through ………….. density tissue.
low
True or false.
The radiation exposure from a chest x-ray is equivalent to 10 days of natural background radiation .
True
Fill in the blank.
You review an MRI scan noting that the joint fluid appears bright and subcutaneous fat is dark. This is characteristic of a T…….. weighted scan
t2
Why is iodine a good contrast agent for x-ray imaging?
High attenuation
Long radioactive half life
Only need a small amount
Produces pink colouration of photographic paper
High attenuation
X-rays are produced when high speed electrons strike a target material. The energy of these electrons can be converted to what, in terms of what is useful in medicine?
- Light photons
- Gamma rays
- Alpha particles
- Microwaves
Gamma rays
Which factors of tissues allow us to distinguish between different tissues on an x-ray image?
- Thickness/distance from source - the longer the distance travelled, the lower the intensity of x-rays detected
- Attenuation - a measure of the material’s ability to attenuate x-rays (higher attenuation = brighter image)
- Oxygen concentration in the tissue
- Fluid content of the tissue
Attenuation - a measure of the material’s ability to attenuate x-rays (higher attenuation = brighter image)
True or false.
Tissues that are more attenuating of x-rays appear brighter on x-rays (i.e. bones are highly attenuating so appear bright white)
True
Which generation of CT scan do modern systems use?
* Generation 1 - dual motion pencil beam scanner in a translate-rotate mechanism
* Generation 2 - dual motion narrow fan beam in a translate-rotate mechanism
* Generation 3 - single motion with a fan beam and rotating detector and source in a rotate-rotate mechanism
* Generation 4 - fan beam with rotating source only and stationary-rotate mechanism
* Generation 5 - scanning electron beam with stationary-stationary mechanism
Generation 3 - single motion with a fan beam and rotating detector and source in a rotate-rotate mechanism
In beta-plus decay, a proton breaks down into what?
- A neutron and a positron
- A proton and neutron
- A proton and electron
- Two protons
A neutron and a positron
What happens when a positron and an electron meet?
* They are converted into two gamma photons travelling in opposite directions
* They form two protons which travel in the same direction
* The positron is converted into an electron and the two orbit one another
* They form one neutron
They are converted into two gamma photons travelling in opposite directions
Why can we use the 18F isotope to monitor metabolism in tissues?
- 18F can be incorporated into fluorodeoxyglucose which the body treats as standard glucose
- 18F emits radiation in high carbon dioxide concentrations
- 18F emits radiation in high oxygen concentrations
- 18F reacts with acetyl CoA, emitting radiation
18F can be incorporated into fluorodeoxyglucose which the body treats as standard glucose
