Some useful revision and questions moodle/powerpoint quiz Flashcards
What does kVp stand for?
Kilovoltage peak, is the peak potential applied to the x-ray tube, which accelerates electrons from the cathode to the anode
What does kVp effect?
kVp controls the penetrating strength of an x-ray beam (beam quality). Whenever an exposure is made, the x-rays must be energetic (strong enough) to adequately penetrate through the area of interest. The higher the kVp, the more likely the x-ray beam will be able to penetrate through thicker or more dense material.
The 2 Chest Radiographs below were taken using different kVp.
Think and make notes about the difference in Contrast and Density seen in the images below.
Can you state which image was taken at a higher kVp? Why?
Chest x-ray A was taken at a lower kVp as less photons penetrated through the lungs than chest x-ray B. We know this because the contrast is lower, meaning you cant easily tell the difference between bone, soft tissue and air as much.
What does mAs stand for?
mAs stands for milli-ampere-second.
What does mAs affect?
mAs stands for milli-ampere-second. 135. It determines how many x-ray photons are produced (quantity). It has no effect on the strength (penetrating power) of the x-ray photons. mAs is a product of multiplying two factors together: time and milliamperage (mA).
The 2 Abdomen Radiographs below were taken of a phantom using different mAs.
Think and make notes about the difference in Contrast and Density seen in the images below.
Can you state which image was taken at a higher mAs? Why?
pelvis x-ray A was taken at a higher mAs, as you can see the differences in contrast and density more easily. For example, you can see the ASIJs better than pelvis x-ray B.
Types of brain haemorrhage
Extradural haemorrhage/haematoma
Subdural haemorrhage/haematoma
Subarachnoid haemorrhage
Intracerebral haemorrhage
How might a patient present with a brain haemorrhage?
Often acute onset of symptoms
Symptoms may include;
Severe headache
Numbness, tingling or weakness of the face, arm or leg, particularly on one side of the body
Dysphagia
Dysphasia
Visual impairment
Change in consciousness level
First line imaging for brain bleeds? why?
CT Brain
Sensitive for pathologies requiring urgent neurological intervention
Widely available
Fast scan times
How does blood show on a CT scan?
Fresh blood- Increased attenuation-HYPERDENSE
Old blood- Decreased attenuation- HYPODENSE
What examination is seen here in image B?
What type of contrast has been used?
What difference has the addition of contrast media made to the visualisation of soft tissue and bone in this region when compared to image A?
Angiogram
Iodine-based omnipaque
What examination is this?
What type of contrast agent has been used?
What difference has the addition of contrast media made to the visualisation of soft tissue and bone in this region?
pulmonary angiogram ct
iodine-based, omnipaque
The vessels are radio plague
What examination is this?
What type of contrast has been used?
Barium meal
Barium
Note to myself, go through all the contrast examations stuff again, and artifacts stuff again
