Flashcards in Radiography Deck (21)
What is fluoroscopy?
A radiograph taken in real time
What makes a radiograph a superimposition?
Cannot determine depth of the image
What color is produced if a lot of x-rays reach the film?
What is the order of tissue radio-opacity?
Metal > Bone > Soft Tissue > Fuid > Fat > Gas
What is the order of image density?
Metal < Bone < Soft Tissue < Fluid < Fat < Gas
Why does fat appear lighter than air?
It is more dense
Why are x-ray films placed into cassettes?
A lot of photons are needed to create an image on film alone, cassette decreases the amount of photons needed to produce an image (More safe)
If the x-ray beam is uneven to the film cassette, which distortion will occur?
If two x-ray beams overlap while taking the image, which distortion will occur?
How is a projection named?
The side the animal is laying on, the direction of the beam's path
What is the Compton Effect and how can it be stopped?
Scatter of photons when an x-ray is taken, need 1" thick lead or double brick barrier to stop photons reaching human
How are radiographs placed on a viewer?
Head to the left, right of animal on our left (As if facing us while lying on its back)
What is ultrasound?
High frequency sound wave that is projected at an object, and the resulting waves are read to indicate shape/presence
What is contained in a transducer/probe of an ultrasound machine?
How is a signal transmitted from the transducer through the body?
Electric current causes Piezo-electric crystals to expand and contract, which lets of a sound wave. The sound wave permeates through tissue and is sent back, which is recorded once again through the expansion and contraction of the Piezo-electric crystals.
Should a high or low frequency be used to detect deep objects?
Should a high or low frequency be used for high resolution?
What are three types of transducers that can be used for ultrasound?
Sector/phased array (Small footprint/area of contact, fan-shaped image, poor near-field image), linear array (Large footprint/area of contact, rectangular shaped image, good for superficial structures), curvilinear array (Small footprint/area of contact, fan-shaped image, decent at superficial structures)
What are the other modes of ultrasound besides B (Brightness, most common)?
A mode: For hearts
M mode: Image against time
What is an acoustic shadow?
When a dense tissue (Such as bone, which reflects 30% of sound) is imaged, there is an area underneath the tissue that is not reached by the sound, causes it to be a black wedge in image