Conventional Radiography
- Created by: EllisA
- Created on: 05-04-18 15:18
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- Conventional Radiography
- What is Conventional Radiography?
- Obtains a 3D image via xrays
- as beam is generated and passed through a patient or detector, producing an image
- different soft tissues attenuate x-ray photons differently on tissue density
- dense- white
- gas/air- black
- TERMS
- Sensitivity: the proportion of people with disease who have a positive test result
- Exposure: Kvp and mAs influence and determine the quantity of rad. to which the patient is exposed to.
- overexposure or underexposure result in loss of contrast therefore, loss of diagnostic info
- controlled by rad: -kilovolt peak -miliamp seconds
- Kilovolt Peak (kVp): the peak voltage applied to the xray tube determining the highest energy of the xray photon
- responsible for acceleration between cathode and anode
- controls quality of beam and contrast
- if kVp increases more scatter is produced
- Miliamp (mA): used to measure electrical current and is equal to one thousanth of an ampere
- mA dettermines no of xrays produced
- patient dose directly proportional to mA
- Exposure Time: kept as sort as possible to minimise motion blur from patient movement, expressed in MS
- Miliamp Seconds: controls density
- milliamp x time = controls wuality or no of photons produced
- Process: 1) beam produced 2)passes through patient is modified 3) variations in energy captured by imaging device 4)data converted into visable image for storage and display
- Via:
- Computed Radiography
- sensors are used instead of film
- more time effiicient and ability to digitally enhance images
- Digital Radiography
- IP stores x-ray energy in proportion to the intensity it recieves
- uses a cassette holding an image plat like an intensifying screen
- Computed Radiography
- Via:
- What is Conventional Radiography?
- DR is faster than CR with lower dose
- Computed Radiography
- sensors are used instead of film
- more time effiicient and ability to digitally enhance images
- Computed Radiography
- Distance: exposure of image receptor according to ISL.
- Distance afects intensity of the xray beam
- TERMS
- Sensitivity: the proportion of people with disease who have a positive test result
- Exposure: Kvp and mAs influence and determine the quantity of rad. to which the patient is exposed to.
- overexposure or underexposure result in loss of contrast therefore, loss of diagnostic info
- controlled by rad: -kilovolt peak -miliamp seconds
- Kilovolt Peak (kVp): the peak voltage applied to the xray tube determining the highest energy of the xray photon
- responsible for acceleration between cathode and anode
- controls quality of beam and contrast
- if kVp increases more scatter is produced
- Miliamp (mA): used to measure electrical current and is equal to one thousanth of an ampere
- mA dettermines no of xrays produced
- patient dose directly proportional to mA
- Exposure Time: kept as sort as possible to minimise motion blur from patient movement, expressed in MS
- Miliamp Seconds: controls density
- milliamp x time = controls wuality or no of photons produced
- OVER EXPOSURE:
- not diagnostic
- black holes appear
- black holes appear
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