Diagnostic Imaging Flashcards
What feature can be used to your advantage when radiographing parts of uneven thickness (ie. deep chested dogs)?
The heel effect
Student #11 ML
McCurnin 10th ed. pg. 446
What is the main source of radiation exposure a vet tech should be concerned about?
Scatter radiation
Student #11 ML
McCurnin 10th ed. pg. 446
What are the 3 factors that must be correctly set to produce a diagnostic radiograph?
kVp
mA
time of exposure
Student #11 ML
McCurnin 10th ed. pg. 447
The distance between the target in the x-ray tube and the surface of the x-ray detector is
Focal-film distance
Student #11 ML
McCurnin 10th ed. pg. 449
When is a grid used?
When the part being radiographed is greater than 10 cm thick
Student #11 ML
McCurnin 10th ed. pg. 451
What is kilovolt peak (kVp)?
the quality factor that regulates the energy of the x-ray beam
Student #10 AJ
McCurins 9th edition pg 481
What is a Cathode of a x-ray machine?
It is a negatively charged side of the x-ray tube that produces electrons from a metal filament when it is heated.
Student #10 AJ
McCurins 9th edition pg 480
What is milliamperage (mA)?
Is the setting controlling the quantity of electrons boiled off the filament in the x-ray tube.
Student #10 AJ
McCurins 9th edition pg 481
What is the anode of an x-ray machine?
It is the positively charge side of the x-ray tube that receives oncoming electrons from the cathode.
Student #10 AJ
McCurins 9th edition pg 481
What is a stationary anode?
Is an anode that block, in the x-ray tube that does not move and is embedded in copper to aid in heat dissipation.
Student #10 AJ
McCurins 9th edition pg 482
What is housed in the PYREX glass envelope?
The PYRIX glass envelope houses the cathode and anode, as well as helps maintain a vacuum environment.
Student #8 KH, McCurnin 10th ed. pg. 444
Portable units vs mobile units?
Portable units can be carried from one location to another such as a farm, while mobile units are medium-powered, wheel mounted units that can be moved around a hospital.
Student #8 KH, McCurnin 10th ed. pg 447
What is a technique chart?
A technique chart provides suggested exposure factors to use based on the anatomic part being radiographed, thickness of tissue, and position of the patient.
Student #8 KH, McCurnin 10th ed. g 451
Cassettes with a solid front made of plastic or light metal such as carbon fiber can reduce the quantity of x-rays needed to make an exposure by up to ____ %?
20%
Student #8 KH, McCurnin 10th ed. pg 453
How should unexposed films be stored and why?
Unexposed films should be stored in a designated unexposed film bin and in a vertical position.
Prevents pieces from sticking together and prevents pressure artifacts.
Student #8 KH, McCurnin 10th ed. pg 455
How does positive contrast media appear on radiographic images?
White or radiopaque
Student #6, AF, McCurnin 10th ed. pg. 469
Which tissues are most readily affected by ionizing radiation?
Skin, lymphatics, hematopoietic and leukopoietic tissues, breast, thyroid, bone, and the germinal epithelium or gonads
Student #6, AF, McCurnin 10th ed. pg. 462
Stochastic effects are a major concern with regard to the technicians exposure to x-rays. How does this result, and what are some examples of this effect?
Stochastic effects result from accumulation of radiation doses over a period of time, and damage may only be evident after years of exposure. Examples of stochastic effects include malignancies, anemias, sterility, and cataracts.
Student #6, AF, McCurnin 10th ed. pg. 462
What is dosimetry?
The measurement of personal radiation exposure.
Student #6, AF, McCurnin 10th ed. pg. 463
When taking radiographs of the thorax, you should expose until during which respiratory phase?
Full inspiration
Student #6, AF, McCurnin 10th ed. pg. 466
Why should your dosimeter badge be stored outside of the radiology area?
So that the radiation exposure that the badge detects is accurate.
Student #3, SC
McCurnin 10th Edition Page:464
What are the three ways technician exposure occurs?
Primary Beam, Scatter Radiation, and Leaking Radiation
Student #3, SC
McCurnin 10th Edition Page:462
Maximum Permissible Dose (MPD)
Maximum dose of radiation a person is allowed to receive during occupational exposure over a specified time.
Student #3, SC
McCurnin 10th Edition Page:463
Identification for radiographs should include what?
Patient/Owner name, Patient/Owner ID number, Date, Name/Location of the practice, and Radiographer’s initials.
Student #3, SC
McCurnin 10th Edition Page:460
What should be placed by the patient at the time of exposure to identify what side the patient is on?
Left or Right marker.
Student #3, SC
McCurnin 10th Edition Page:462
What are the five essential components that are needed to create an x-ray beam?
- A source of electrons
- A method of accelerating those electrons
- An obstacle-free path to allow electrons to move at top speed
- A target for the electrons to interact with
- A vacuum environment
Student #14, Sp
McCurnin 10th Edition pg: 444
Is a kVp or a mA produced by a high-voltage?
kVp
Student #14, Sp
McCurnin 10th Edition pg: 445
Santes’s rule is a estimate of the amount of kVp needed. What is the equation for Sante’s Rule?
(2X thickness of tissue in cm) + distance = kVp
Student #14, Sp
McCurnin 10th Edition pg: 449
What is a Caliper?
A caliper is used to measure the thickness of the anatomic area in the direction that the beam passes through the patient.
Student #14, Sp
McCurnin 10th Edition pg: 449
The gelatin matrix on a x-ray film is protected by a thin covering called?
Supercoat
Student #14, Sp
McCurnin 10th Edition pg: 453
What are the three types of positive contrast agents, and indications?
-Barium sulfate (upper and lower GI examinations)
-Soluble radiopaque ionic contrast (PO for GI, IV for venous/arterial studies)
-Nonionic organic iodides (intrathecally for myelography)
Student #4, BE, Pg 507
Negative contrast examples and uses?
-Radiolucent gases such as air, nitrous oxide, oxygen, and carbon dioxide can be used to distend hollow structures in the body.
Student #4 BE, Pg 507
How does hair interfere with an ultrasound? (Why do we need to shave P’s?)
-Ultrasound beams are reflected when the beam intersects air, hair traps in air which will interfere as the reflection will bounce back prior to entering the body.
Student #4, BE, Pg 511
Should artifact be ignored on an ultrasound?
-Nope! Ultrasound artifacts can provide accurate clues to the makeup of the ultrasound image and therefore shouldn’t be ignored.
Student #4, BE, Pg. 512
How long should a complete abdominal ultrasound take?
-20-30minutes as one must compare organs at similar control settings and depth to determine normal from abnormal tissues.
Student #4, BE, Pg 513
What can cause ghost images?
taking images in succession too quickly, double exposure and not erasing the CR plate.
#19 MW
McCurnin 10th ed. pg. 457
What are common causes of white spots in images?
Hair, dirt or other particles tapped in the cassette.
#19 MW
McCurnin 10th ed. pg. 457
Allows transmission of digital data across the internet from private practices to referral centers
Teleradiology
#19 MW
McCurnin 10th ed. pg. 458
What are deterministic effects?
These are effects seen shortly after (radiographic) exposure, such as sunburns, but these are uncommon.
#13 KM
McCurnin 10th ed. pg. 462
What is the maximum permissible dose for occupational personnel?
0.05 Sv per year
#13 KM
McCurnin 10th ed. pg. 463
What are the collimation borders for abdominal radiographs?
Just cranial of the xiphoid process and caudal to the greater trochanters.
#13 KM
McCurnin 10th ed. pg. 467
What is the focal spot?
The area of the target where electrons collide. A smaller sized focal spot will produce good clarity and sharpness.
#13 KM
McCurnin 10th ed. pg. 445
What does DICOM stand for?
Digital imaging and communication in medicine.
#13 KM
McCurnin 10th ed. pg. 457
The time during which electrons are released from the focusing cup and accelerated across the tube for x-ray production to occur is referred to as what?
Exposure Time
Student #16 ER
McCurnin 10th Edition pg 485
What degree is the target of the anode oriented at, allowing the x-rays produce to be redirected out of the tube towards the patient?
20-degree angle
Student #16 ER
McCurnin 10th Edition pg 481
Increasing the kVp will increase the number of x-ray photons passing through the patient and will cause what to occur to the film?
Increased film blackness
Student #16 ER
McCurnin 10th Edition pg 486
The scale of contrast on radiographs refers to which of the following?
The number of shades of gray
Student #16 ER
McCurnin 10th Edition pg 486
The contrast of a radiograph can be increased or decreased by adjusting which setting?
kVp
Student #16 ER
McCurnin 10th Edition pg 486
what should be done before any radiograph is taken?
Remove any metal like a leash, collar and or harness
Student #20
McCurnin 10th Edition pg 466
What is a protection officer
This is something that every clinic should have that is in charge of maintaining radiation safety. This includes maintaining the dosimeter badges, machines are calibrated, and that there is a proper technique chart made.
Student #20
McCurnin 10th Edition pg 464
Foreshortening
This is when one part of the pt is on the image receptor and the other is lifted off. This makes it where the image looks shorter than it actually is.
Student #20
McCurnin 10th Edition pg 460
What is the degree of darkness on an image called?
radiographic density
Student #20
McCurnin 10th Edition pg 458
Define hyperechoic vs hypoechoic
5 SF
Hyperechoic: structure in an ultrasound that appears brighter than surrounding structures
Hypoechoic: structure in ultrasound that appears darker than surrounding structures
McCurnin’s 9th ed. pg 512
What are the most common indications for performing a CT or MRI scan in veterinary medicine?
5 SF
Neurological examinations of brain/spinal cord
McCurnin’s 9th ed. pg 516
Why is TIVA (total IV anesthesia) commonly used when performing MRIs?
5 SF
Absolutely no metal can be near the MRI machine, so anesthesia machines/monitoring equipment can’t be used. The patient needs to be heavily sedated/anesthetized for a long period of time because any movement of the patient will severely effect the image.
McCurnin’s 9th ed. pg 517
Three methods of radiation safety/protection
5 SF
Time, distance, and shielding
McCurnin’s 9th ed pg 504
A safelight may be used in a darkroom when processing x-ray films for a short period of time. What are three requirements for this light?
18 BKS
- 15 watts or less
- At least 4 feet away from workspace
- Correct color filter to avoid damaging exposed films (usually dark red is best)
McCurnin’s 9th ed. pg 495
What causes the difference in color between bone and thin tissues in an x-ray image?
18 BKS
Bone tissue absorbs x-rays, blocking exposure to the film. This makes them appear white on the film. Thin tissues allow x-rays to penetrate easily, resulting in more exposure to the film, so they appear darker (gray).
McCurnin’s 9th ed. pg 497
A result of accumulating radiation doses over a period of time, including malignancies, anemia, sterility, cataracts, and sunburn effects
18 BKS
Stochastic effects
McCurnin’s 9th ed. pg 501
When radiation damages the DNA of the reproductive cells, in which the damage effects future generations of the recipient rather than the actual recipient
18 BKS McCurnin’s 9th ed. pg 501
Genetic effects
Why is iodinated contrast used for CT scans?
18 BKS McCurnin’s 9th ed. pg 516
Iodinated contrast administered IV will highlight vascular structures and neoplasms will have a characteristic contrast enhancement pattern, aiding in the visualization of problem areas in the patient.
To take advantage of the heel effect and achieve more uniform density, which side of the xray tube (anode or cathode) should the thickest part of the patient be directed?
5 SF
Cathode side- the x-ray beam is more intense on the cathode side than at the center of the xray beam and anode side
McCurnin’s 9th ed. pg 483
What is the Potter-Bucky Diaphragm and how does it work?
A moveable grid. The movement of the diaphragm is timed to suit a particular exposure, and the grid moves across the image receptor during the exposure so that the grid lines are not visible on the resulting film.
#12 JL
McCurnin’s 10th ed. Pg. 451
What are two disadvantages of using the Potter-Bucky Diaphragm?
- It requires a much longer exposure time to make the lead strips move fast enough to blur
- The movement of the grid is loud which can startle the patient and cause motion artifacts to occur.
#12 JL
McCurnin’s 10th ed. Pg. 451
Describe the Air Gap Technique
Increase the distance between the patient and the surface of the receptor.
#12 JL
McCurnin’s 10th ed. Pg. 451
Does the Air Gap Technique reduce the amount of scatter radiation produced?
No, but because of the increased distance, less scatter radiation reached the image receptor.
#12 JL
McCurnin’s 10th ed. Pg. 451
When positioning for a lateral pelvic radiograph, which side should be down?
The affected side
#12 JL
McCurnin’s 10th ed. Pg. 467
What is a rotating anode?
A rotating anode is one that spins on an axis to dissipate heat. They can use higher currents, shorter exposure times, and have a smaller focal spot. They can use more electrons without losing image quality.
Student #7, HHS
McCurnin 10th edition, pg:445
What aspect of the radiographic image does milliamperage control?
Density, the higher the milliamperage the darker the image, and the lower the lighter.
Student #7, HHS
McCurnin 10th edition, pg:449
What types of digital radiography are commonly used in veterinary medicine?
digital fluoroscopy (DF), computed tomography (CT), diagnostic ultrasonography (DUS), nuclear medicine (NM), magnetic resonance imagining (MRI), digital radiography (DR), and computed radiography (CR)
Student #7, HHS
McCurnin 10th edition, pg:455
What is PACS?
Picture archival computing system, this is the remote hard drive for permanent data storage and allows images to be shared between workstations within a hospital or to other hospitals.
Student #7, HHS
McCurnin 10th edition, pg:457
When should chemical restraint be used?
When total immobilization or relaxation is needed.
In cases where the patient is fearful and/or aggressive.
In states that prohibit manual restraint.
Student #7, HHS
McCurnin 10th edition, pg:468
What are the two primary diagnostic imaging techniques available to the veterinarian?
1) Radiology
2) Ultrasonography
#1 MA
McCurnin 10th ed. pg 443
Who’s responsibility is it to provide useful diagnostic images?
Veterinary Technicians
#1 MA
McCurnin 10th ed. pg 443
What is the X-ray tube composed of?
A negatively charge cathode and a positively charged anode, enclosed in a vacuum environment which is maintained by a glass envelope. The glass envelope is surrounded by a metal casing / house
#1 MA
McCurnin 10th ed. pg 444
Why is everything inside the X-ray tube enclosed within a metal housing?
To prevent the escape of stray X-rays
#1 MA
McCurnin 10th ed. pg 444
What is the primary source of radiation exposure for technicians who manually restrain?
Scatter radiation
#1 MA
McCurnin 10th ed. pg 445
What do we include for a pelvic radiograph?
Tip of the iliac wings to the distal patellae.
TSR Student #17
McCurnin 10th edition page 467
What do we include for a thoracic radiograph?
Thoracic inlet and just caudal to the 13th rib. Include the spine and the sternum for lateral views.
TSR Student #17
McCurnin 10th edition page 467
What do we include for skull radiographs?
Tip of nose to base of skull.
TSR Student #17
McCurnin 10th edition page 468
What does radiolucent look like on a radiograph ?
Dark.
TSR Student #17
McCurnin 10th edition page 459
Why does air look radiolucent?
More x-rays are able to pass through air. Theses x-rays interact with the image receptor and that causes the image to look darker.
TSR Student #17
McCurnin 10th edition page 459
Are radiographs part of the patient’s legal record?
Yes
#9 KJ McCurnin 10th ed. pg 460
How often should lead protective devices be thoroughly checked?
Annually
#9 KJ
McCurnin 10th ed. pg 466
What is echogenicity in regards to ultrasonography?
Echogenicity refers to the strength or amplitude of the returning echoes. Echogenicity is a relative term used, but is helpful when viewing structures within the body
#9 KJ
McCurnin 10th ed. pg 474
How often should you clean the endoscope?
Between every patient to avoid spreading pathogens
#9 KJ
McCurnin 10th ed. pg 475
How should an endoscope be stored when not in use?
It should be hung vertically, and outside of the original box it came in. This prevents the growth of bacteria on the endoscope.
#9 KJ
McCurnin 10th ed. pg 475
Why should lead aprons never be folded when put away and rather hung up?
When the apron is folded it can cause the lead to bend and then crack, allowing radiation to get through to the technician.
Student #2 vc
McCurnins 10th ed. pg 466
What does the filament (in the x-ray tube) produce when it is heated up?
The amount of heat applied to the filament determines the number of electrons that are produced.
Student #2 vc
McCurnins 10th ed. pg 444
What does the inverse square law state?
It states that the intensity of the x-ray beam at a given point is inversely proportional to the square of the distance from the x-ray source.
Student #2 vc
McCurnin 10th ed. pg 450
Fast screen vs slow screen on a cassette?
Fast screen requires less radiation than a par screen to produce the same degree of darkness on the radiograph.
Slow screen requires more radiation to produce a radiograph of sufficient density.
Student #2 vc
McCurnin 10th ed. pg 453
A slow screen is best suited for which kinds of animals?
Birds or exotics animals
Student #2 vc
McCurnin 10th ed. pg 453
What does the term “dose creep” refer to?
Dose creep refers to the amount of noise adversely affecting the quality of the image.
#15
HP
McCurnin 9th ed. pg 504
The dose equivalent used to go by the unit Sievert (Sv), but is now being replaced by rem. What is the conversion of Sievert to rem?
1 Sv= 100 rem
#15
HP
McCurnin 9th ed. pg 502
What is the benefit of a focal spot?
The focal spot allows for a sharper image to be created
#15
HP
McCurnin 9th ed. pg 481
If an image is taken using high kVp, will the image be lighter or darker?
The image will be darker, as more x-rays pass through the structures.
#15
HP
McCurnin 9th ed. pg. 486
What is the focal film distance (FFD) for large animals?
90 - 105 cm (36 - 42 in)
#15
HP
McCurnin 9th ed. pg. 487
