Diagnostic Imaging Flashcards

1
Q

Diagnostic imaging types?

A

Diagnostic imaging types?

.Radiography

.Ultrasound

.Nuclear scintigraphy (gamma scan)

.Endoscopy

.Computed tomography (CT/ CAT scan)

.Magnetic resonance imaging (MRI)

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2
Q

X-rays?

A

X-rays?

.Are a type of radiation called electromagnetic waves. The x-ray will show different shades of B&W because different tissues absorb different amounts of radiation.

.Have a short wave-length and high frequency. They are part of the electromagnetic spectrum; this is composed of energy waves.

.Used to detect dislocations & fractures of bones , cancers, pneumonia, foreign bodies, organs diseased ect.

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3
Q

Ultrasound?

A

Ultrasound?

.Uses high-frequency sound waves that are sent into the body by a transducer and when reflected from interfaces between the tissues are collected by the transducer and an image forms on a computer screen.

.Used to demonstrate soft tissues, not always visible on radiographs e.g. abdomen, tendons, ligaments and soft tissue masses.

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4
Q

Magnetic resonance imaging?

A

Magnetic resonance imaging?

.Produces images of bodily organs by measuring the response of the atomic nuclei of body tissues to high-frequency radiowaves when placed in a strong magnetic field.

.Does not use ionising radiation. Is used to produce an image by mapping the locations of the protons of the body tissues.

.Ideal for CNS & spinal column & soft tissues within joints.

.Patient is exposed to a large magnetic field. The magnet has a strength of between 0.2 - 2 telsa(T)

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5
Q

Nuclear scrintigraphy (gamma scan)?

A

Nuclear scrintigraphy?

.Radioisotopes attached to drugs that travel to a specific organ or tissue are taken internally.

.Will demonstrate the function of a tissue or organ and will show where a problem is but no exact diagnosis.

.Mainly used for cats and horses

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6
Q

Computed tomography?

A

Computed tomography?

.Computerised x-ray imaging procedure in which a narrow of x-rays is aimed at a patient and quickly rotated around the body (creates slides of the body).

.Uses a x-ray tube mounted opposite a detector, the tube emits x-rays in a fan shape that passes through the patient to reach the detector. The x-ray tube and the detector move around the patient (3D scan).

.Ideal for skeletal & CNS and diagnoses internal organ injuries in 3D. They are an advanced x-ray device.

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7
Q

Every element is?

A

Every element is?

.Made up of atoms. These atoms contain nucleus, composed of neutrons and protons, surrounded by orbiting electrons

.Protons - always positively charged

.Neutrons - neutral & have no charge

.Orbiting electrons - negative and orbit the necleus in shells.

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8
Q

Hertz (Hz)?

A

Hertz (Hz)?

.Frequency measurement

.1 Hz is equal to 1 cycle per second

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9
Q

Inverse square law?

A

Inverse square law?

.The further away from the x-ray tube you can get, the lower the intensity of x-rays reaching the body and causing damage.

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10
Q

Electric current?

A

Electric current?

.Formed when electrons flow through a conductor.

.If the electrons flow in one direction, then a direct current (DC) is generated and if in alternating directions will be an alternating current (AC).

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11
Q

Cathode?

A

Cathode?

.The negative part of the x-ray tube and is made up of filament and focusing cup.

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12
Q

Anode?

A

Anode?

.Is the positive part of the x-ray tube.

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13
Q

X-ray tube?

A

X-ray tube?

.Produces the x-ray and is composed of a pyrex tube surrounding the anode and cathode.

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14
Q

X-ray beam?

A

X-ray beam?

.May be absorbed by the tissues of the patient.

.Has minimal absorption but if scattered will be absorbed more.

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15
Q

Milliamperage?

A

Milliamperage?

.Higher the milliamperage, the higher the heat and the more electrons produced.

.Heating releases electrons from the surface of the filament wire. The electrons collect in the focusing cup.

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16
Q

Focusing cup?

A

Focusing cup?

.These electrons contain electrical potential and when a charge is applied will flow from negative to positive (cathode to anode).

17
Q

Kilovoltage?

A

Kilovoltage?

.Higher kilovoltage selected the faster the electrons will move towards the target, giving higher energy x-rays.

18
Q

Amperage (mA)

A

Amperage (mA)?

.Controls the amount of heat applied to the cathode and changes the quantity of x-rays produced, which affects the density or degree of blackening of the film

.Increase amperage to blacken film.

.Setting mA’S - time should be as low as possible and mA should be as high as possible.

.mA x time(s) = mAs

19
Q

Voltage (KV)?

A

Voltage (KV)?

.Voltage alters the speed at which the electrons accelerate across the tube and strike the target and affects the contrast of the image.

.Low voltage - for small patients

20
Q

X-ray patients should be positioned?

A

X-ray patients should be positioned?

.100cm from the x-ray tube to table.

21
Q

Production of x-ray diagram?

A

Production of x-ray diagram?

Filament ➡️ mA applied ➡️ electrons produced ➡️ KV between cathode & anode ➡️ electrons accelerated across tube ➡️ electrons hit target ➡️ heat and x-rays produced

22
Q

Radioplaque?

A

Radioplaque?

.Very dense tissue e.g. bone then the x-ray will be stopped.

23
Q

Radiolucent?

A

Radiolucent?

.Less dense tissue e.g. lung will not stop the x-rays and will pass through the tissues.

24
Q

Tissues?

A

Tissues?

.Higher the atomic number the more absorption will occur e.g. bone absorbs more than tissue.

25
Q

Collimator?

A

Collimator?

.Will reduce or increase the area exposed to radiation.

.Collimation - limiting the size of the beam to the required part of the patient.

26
Q

Scatter?

A

Scatter?

.Reducing the voltage as much as possible will reduce scatter and a collimator.

27
Q

Grids?

A

Grids?

.Tools in the reduction of scattered radiation reaching the film and remove 85 - 95% of scattered radiation to stop the film fogging.

28
Q

Effects of radiation?

A

Effects of radiation?

.X-rays will interact with the tissues within the human body, causing ionisation in which the tissue molecules can be broken or damaged and die if severe.

29
Q

Primary beam?

A

Primary beam?

.At least 2m away when x-ray in process.

30
Q

X-ray PPE?

A

X-ray PPE?

.Lead aprons and thyroid shields should be used when remaining in x-ray room and stand 2m away with door closed.

31
Q

Dosimeters?

A

Dosimeters?

.Measure the dose of radiation received by the body.

32
Q

Contrast radiography?

A

Contrast radiography?

.Substances that,when administered to the body, will enhance areas where radiographic contrast is low. They have a higher atomic number than soft tissue and will therefore appear white on the x-ray.

33
Q

Contrast substance types?

A

Contrast substance types?

.Barium sulphate suspension (baritop) used for digestive system.

.Iodine based solution used for subarachnoid or spinal areas.

.Warm contrast solution before injecting

34
Q

Ultrasound image?

A

Ultrasound image?

.Is formed by the reflection of the ultrasound waves within the body.

35
Q

Transducer?

A

Transducer?

.The hand held probe used for examinations and converts electrical energy to mechanical energy from the ultrasound beam.

36
Q

Coupling gel?

A

Coupling gel?

.Placed on transducer to ensure complete contact with skin.

37
Q

Before MRI scan?

A

Before MRI scan?

.Remove all magnetic things from patient e.g. collar

.Have no metallic objects in MRI room

38
Q

Main beam?

A

Main beam?

.The main beam that is produced when making an exposure is called the primary beam.

.This is the biggest hazard to people & no part of the operator’s body should ever be placed in the primary beam.

39
Q

Secondary radiation or scatter?

A

Secondary radiation or scatter?

.Producer when particles of energy from the primary beam hit a surface e.g. tissue and cause the production of lower-energy particles.

.These lower-energy particles bounce off the surface at random and like x-rays, travel in straight lines.

.Everyone who is involved with radiography must be protected from it.