Diagnostic Imaging Flashcards
Diagnostic imaging types?
Diagnostic imaging types?
.Radiography
.Ultrasound
.Nuclear scintigraphy (gamma scan)
.Endoscopy
.Computed tomography (CT/ CAT scan)
.Magnetic resonance imaging (MRI)
X-rays?
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.
Ultrasound?
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.
Magnetic resonance imaging?
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)
Nuclear scrintigraphy (gamma scan)?
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
Computed tomography?
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.
Every element is?
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.
Hertz (Hz)?
Hertz (Hz)?
.Frequency measurement
.1 Hz is equal to 1 cycle per second
Inverse square law?
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.
Electric current?
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).
Cathode?
Cathode?
.The negative part of the x-ray tube and is made up of filament and focusing cup.
Anode?
Anode?
.Is the positive part of the x-ray tube.
X-ray tube?
X-ray tube?
.Produces the x-ray and is composed of a pyrex tube surrounding the anode and cathode.
X-ray beam?
X-ray beam?
.May be absorbed by the tissues of the patient.
.Has minimal absorption but if scattered will be absorbed more.
Milliamperage?
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.
Focusing cup?
Focusing cup?
.These electrons contain electrical potential and when a charge is applied will flow from negative to positive (cathode to anode).
Kilovoltage?
Kilovoltage?
.Higher kilovoltage selected the faster the electrons will move towards the target, giving higher energy x-rays.
Amperage (mA)
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
Voltage (KV)?
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
X-ray patients should be positioned?
X-ray patients should be positioned?
.100cm from the x-ray tube to table.
Production of x-ray diagram?
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
Radioplaque?
Radioplaque?
.Very dense tissue e.g. bone then the x-ray will be stopped.
Radiolucent?
Radiolucent?
.Less dense tissue e.g. lung will not stop the x-rays and will pass through the tissues.
Tissues?
Tissues?
.Higher the atomic number the more absorption will occur e.g. bone absorbs more than tissue.
Collimator?
Collimator?
.Will reduce or increase the area exposed to radiation.
.Collimation - limiting the size of the beam to the required part of the patient.
Scatter?
Scatter?
.Reducing the voltage as much as possible will reduce scatter and a collimator.
Grids?
Grids?
.Tools in the reduction of scattered radiation reaching the film and remove 85 - 95% of scattered radiation to stop the film fogging.
Effects of radiation?
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.
Primary beam?
Primary beam?
.At least 2m away when x-ray in process.
X-ray PPE?
X-ray PPE?
.Lead aprons and thyroid shields should be used when remaining in x-ray room and stand 2m away with door closed.
Dosimeters?
Dosimeters?
.Measure the dose of radiation received by the body.
Contrast radiography?
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.
Contrast substance types?
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
Ultrasound image?
Ultrasound image?
.Is formed by the reflection of the ultrasound waves within the body.
Transducer?
Transducer?
.The hand held probe used for examinations and converts electrical energy to mechanical energy from the ultrasound beam.
Coupling gel?
Coupling gel?
.Placed on transducer to ensure complete contact with skin.
Before MRI scan?
Before MRI scan?
.Remove all magnetic things from patient e.g. collar
.Have no metallic objects in MRI room
Main beam?
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.
Secondary radiation or scatter?
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.
