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Veterinary Radiology
Veterinary Radiology/Xrays
| Term, Question | Definition / Answer |
|---|---|
| Define Amplitude: | Height of an energy wave |
| Define Frequency: | The number of waveforms that strike an object during a given time period |
| The most common Blue-emitting phosphor | Calcium tungstate |
| What is the benefit of using screened film vs. non-screened film? | Screened = lower radiation exposure time, minimizes blur potential Non-Screened = requires higher mA & longer exposure time. |
| Define X-Ray: | Nonluminous, electromagnetic radiation |
| Cathode filaments are made of: | Thoriated tungsten |
| What is the function of a Bucky Tray? | Holds the film cassette under the tabletop |
| DICOM is an acronym for: | digital imaging and communications in medicine |
| Electrons are generated at the: ______ and travel to the: _______ | Cathode; Anode |
| What is the function of a collimator? | Used to restrict the size of the x-ray beam and reduce the amount of scatter radiation |
| What is the function of a focusing cup? | Allows excited electrons to be released from the cathode in a straight pattern towards a focused target on the anode. |
| Define Time as it relates to radiography: | Duration in seconds the anode has a positive charge and is receiving electrons |
| Define Kilovoltage potential (kVp) | Energy of electrons when they reach the anode |
| Define Milliamperage (mA) | Controls the quantity of electrons that will be produced and released from the filament during x-ray production |
| Usually associated with the contrast of the image: | Kilovoltage |
| Higher kV & lower mA setting is used for: | Soft tissue (abdominal/thoracic); varied contrast, more shades of grays |
| Lower kV & higher mA setting is used for: | Extremities where sharper differences are needed; less shades of gray |
| Define Fluoroscopy: | Live-time image of the area being assessed. Multiple x-rays that make a mini video |
| What is the function of an Intensifying screen? | Helps decrease the amount of radiation needed to produce a diagnostic image; increases contrast of the image |
| Able to absorb more x-rays per crystal & produce more light per absorbed photon | Rare earth phosphors |
| The amount of radiation needed to produce an image on the film is associated with: | Screen Speed |
| Grids should be used when the thickness of the area to be X-rayed is _____cm or more | 10cm |
| What is the function of a Grid and where is it placed? | Decreases scatter radiation while increasing contrast of the radiograph. Placed between the animal and film. |
| The acceleration of the electrons and their striking energy is determined by the: | kVp |
| Define a "RAD": | Unit of absorbed dose of ionizing radiation |
| Define Roentgen: | Measure of radiation and x-ray machine production |
| Define REM (Roentgen equivalent man): | Expresses the dose equivalent that comes from exposure to radiation |
| What is meant by MPD (maximum permissible dose)? | It is the maximum dose of radiation a person can receive in a specific period of time |
| The degraded rays after they have had collision with tissues or structures are defined as: | Scatter radiation |
| What is the best means to reduce exposure to x-ray radiation? | Minimize the duration of time x-rays are being released |
| Define Halation: | Light reflected back off the base resulting in a shadow appearance |
| Why do you store film in an upright position? | It is pressure sensitive. |
| Single emulsion film is best used for: | CT (computed tomography) and MRI (magnetic resonance imaging) |
| What is the chemical: Phenidone used for when processing film? | To produce gray densities on the film |
| What is the chemical: Hydroquinone used for when processing film? | To increase the contrast of the image and black areas of the film |
| Hydroquinone is sensitive to: | Oxygen, temperature and the age of the chemical |
| What is the function of the fixer when developing film? | To remove unchanged silver halide crystals from the emulsion layer on the film. |
| The ideal wash time for film is: | 12 minutes with flowing water |
| The pH of the fixer is: | Acidic |
| What wattage is used for safelight bulbs? | 7-10 watts |
| What are the six components of the developer? | Developing agents, activator, restrainer, preservative, hardener, solvent |
| Image detail refers to: | The degree of sharpness of the image |
| The biggest factor that affects the detail of the image is: | Focal-film distance (FFD): distance between x-ray tube and film |
| The major factor affecting density is the: | mAs setting (Milliamperage) |
| Why is a higher kVp preferred for thoracic imaging? | They are more uniformly absorbed amongst body tissues resulting in lower contrast. |
| If the film contrast is too dark or over-penetrated, what should you adjust? | Decrease the kVp by 10-15% |
| If the film density is too dark, what should you adjust? | Decrease the mAs by 30-50% |
| Sante's rule states that kVp should be approx:____ plus ____ the measurement in cm. | 40, twice |
| When should the tabletop method be used? | When the anatomic measurement is less than 10 cm |
| The penetrating power of the incident photons is concerned with what? | Kilovoltage (kV) |
| Contrast is mostly dependent upon: | Increases or decreases in milliamperage and time |
| You should collimate your field size in as much as possible, because if you don't you'll have increased scatter. This scatter will be more noticeable at: | higher kVp, thicker patient, and larger field size. |
| If the xray machine is set at 50kV when it should have been set at 60 kV, the film would look: | light |
| The quality of a beam refers to the____ and is controlled by the ___ | Penetration of the beam; kV |
| Compare kV at 40 and at 80. The kV at 80 will have: | A higher-quality beam |
| When is x-ray film most vulnerable? | When it's wet during development |
| When does the film get initially rinsed in water? | Between the developer and fixer tanks |
| The exposure time for nonscreen film can run as high as | 2 seconds |
| Image noise refers to: | Unwanted, random variations in shades of gray produced on a digital radiograph from electric or quantum interference. |
| Increased noise increases or decreases image contrast? | Decreases |
| What is Dose Creep? | Increases in exposure factors made in an attempt to reduce the amount of image noise |
| How soon should you process an image plate after exposure? | As soon as possible. The electrons only retain the image for a few hours. 25% is lost within 8 hours. |
| Cassettes and IPs are not required for which type of imaging? | Digital Radiography (DR) |
| What is DQE? | Detective quantum efficiency = the sensitivity and accuracy of the system expressed as a % of x-ray energy that strikes the detector. |
| What is a scintillator? | Material that fluoresces when exposed to the x-ray beam |
| What is a histogram? | The graphical representation of the signal intensity of each of the pixel values. |
| Windowing controls the _____ and leveling controls the ______ | range of densities displayed; brightness of the image |
| Which imaging method is preferred for Esophagography? | Fluoroscopy or standing imaging. Lateral and dorsal are the least effective. |
| What are BIPS and what are they used for? | BIPS = Barium impregnated polyethylene spheres. Used to assist in diagnosing GI obstructions, motility and gastric emptying disorders. |
| What is the purpose of performing a lower GI study? | To evaluate the cecum, colon and rectum to help identify extramural masses, lesions, disease of ileocolic valves and morphology. |
| What is the purpose of performing an upper GI study? | To evaluate the morphology of the stomach & small intestines and visualize extramural, mural and intramural lesions of the GI tract. |
| What are the four types of contrast agent? Which one is considered a negative contrast? | Soluble (1) ionic & (2) nonionic radiopaque media, (3) insoluble inert radiopaque media, (4) radiolucent gases. Radiolucent = negative contrast. |
| What two studies are part of an excretory contrast study? | Nephrogram (flow of blood to kidney) and Pyelogram (renal pelvis & ureters). |
| What is Azotemia? | an excess of urea and other nitrogenous wastes in the blood as a result of kidney insufficiency |
| What is the best position for excretory contrast studies? | Right lateral due to separation of the right and left kidney |
| Which positive contrast compound is not diluted by secretion or absorbed through the intestine? | Barium Sulfate |
| Which contrast agent is used if the Veterinarian suspects a perforation of the small bowel? | Triiodinated compound |
| The Radiolucent gases used as negative contrast agents include: | Air, oxygen, carbon dioxide and nitrous oxide |
| Areas in an ultrasound that do not generate an echo are described as: | Anechoic - appear black on ultrasound. Usually fluid filled structures. |
| Areas with returning echoes on an ultrasound that are the same as the surrounding tissues | Isoechoic |
| Which transducer array is ideal for use in abdominal imaging? | Microconvex curvilinear transducers |
| What shape does a sector array transducer produce? | Wedge/pie-shaped image |
| What affect does increasing the intensity of the sound wave (amp) have on an ultrasound? | Higher voltage = louder sound = louder echoes = brighter image. |
| What does the gain control modify? | The strength of the returning echo |
| What is doppler ultrasound primarily used for? | Evaluating blood flow |
| Abdominal focused assessment w/sonography for trauma (aFAST) requires what type of patient placement? | Right lateral recumbency |
| Loss of amplitude in an ultrasound wave is referred to as: | Attenuation |
| Which gas is used during endoscopic insufflation and why? | CO2 because it has a reduced risk of air embolisms and you can control the flow rate. |
| Caudal aspect of the hind limb, distal to the tarsus: | Plantar |
| Caudal aspect of the forelimb distal to the carpus: | Palmar |
| ____ and ____ within the structures of the abdominal cavity affect radiographic contrast. | Gas; Fluid |
| Abdominal radiographs are exposed during: | respiratory pause (after full exhalation; before inspiration) to minimize motion artifacts and position diaphragm cranially for better visualization of other organs. |
| What is the proper positioning for Lateral projection? | Right lateral recumbency w/ forelimbs extended cranially and hindlimbs extended caudally. Foam pad under sternum to avoid rotation. Measure and Center: Slightly caudal to last rib. |
| What is the proper positioning for Ventrodorsal projection? | Dorsal recumbency in V-trough; sand/foam bags on lateral wall if needed; extend forelimbs cranially and hindlimbs caudally. Measure and center: caudal aspect of last rib. |
| When should the lateral decubitus be used? | When there is a suspicion of fluid or gas within the abdominal cavity or if standard ventrodorsal position would compromise the animal |
| What is the proper positioning for Ventrodorsal projection using a horizontal beam (lateral decubitus)? | Right lateral recumbency w/ forelimbs extended cranially and hindlimbs extended caudally. Foam pad under sternum to avoid rotation. Measure and Center: Slightly caudal to last rib. |
| How can you confirm when a DV or VD thoracic image is properly positioned? | When the sternum appears superimposed on the thoracic vertebrae |
| Thoracic imaging is primarily used to evaluate: | The heart and lungs |
| When lesions are suspected in one lung, the patient should be positioned: | with the unaffected lung down on the table |
| Which position is preferred for evaluation of the heart? | Dorsoventral (DV) |
| Which position is preferred for evaluation of the Lungs? | Ventrodorsal (VD) at full inspiration |
| What is the caudal collimation border for the ventrodorsal projection of the thorax? | 1st lumbar vertebrae |
| Which characteristic can confirm proper position for the lateral view of the abdomen? | The lateral process on the right side of the vertebra should superimpose over the ones on the left side |
| What are the collimation borders for Lateral projection of the abdomen? | Cranial: halfway between caudal border of scapula and xiphoid Caudal: coxofemoral joints Dorsal: Spinous processes of vertebral column Ventral: Sternum |
| What are the collimation borders for Ventrodorsal projection of the abdomen? | Lateral: abdominal wall within V-trough Cranial: halfway between caudal border of scapula and xiphoid Caudal: coxofemoral joints |
| When is the modified lateral projection of the abdomen used? | To evaluate the entire length of the urinary tract when hindlimbs would obscure urethra if in standard lateral position |
| What are the collimation borders for Lateral projection of the thorax? | Cranial: Thoracic inlet | Caudal: 1st lumbar vertebrae | Dorsal: spinous processes | Ventral: xiphoid | Entire rib-cage in collimated area |
| What are the collimation borders for Ventrodorsal projection of the thorax? | Cranial: Thoracic inlet | Caudal: 1st lumbar vertebrae | Lateral: body walls | V-trough entirely within collimated area |
| What are the collimation borders for Lateral projection of the pelvis? | Cranial: edge of ilium | Caudal: border of ischium | Dorsal: include 1/3 of femurs | Ventral: spinous processes of vertebrae |
| How are the hindlimbs positioned for a Ventrodorsal Extended hip projection? | Fully extended evenly & parallel to each other; stifles rotated medially & parallel to each other; patellas centered over trochlear groove; tail aligned w/spine |
| Where is the cassette placed for a hindlimb image and why? | On the tabletop b/c the measurement for dog & cat limbs is fairly small. |
| How are the hindlimbs positioned for a Craniocaudal projection of the femur? | Place band of tape around femurs proximal to the stifles and pull femurs together so patellas are straight over distal femurs |
| What is the preferred position for mediolateral projection of the femur? | Femoral head toward cathode end of x-ray tube. |
| What is the collimation for the flexed lateral projection of the tarsus? | From the distal portion of the tibia to proximal portion of metatarsals |
| What is the collimation for a mediolateral projection of the femur? | From the coxofemoral joint to the stifle |
| Where is the primary beam centered for the lateral projection of the pelvis? | Greater trochanter of the femur |
| You can tell when a patient is in proper position for Ventrodorsal abdominal radiograph when: | there is symmetry of the wings of the ilium and ribs, and central alignment of the spinous processes within the vertebrae. |
| Proper thoracic lateral positioning is evidenced by: | the right and left ribs over the heart will be superimposed |
| Proper thoracic Ventrodorsal or Dorsoventral positioning is evidenced by: | The sternum appearing to be superimposed on the thoracic vertebrae. |
| If you are asked to take a lateral decubitus view of the thorax, you would essentially be taking a: | Ventrodorsal with a horizontal beam |
| How many baseline dental radiograph images are needed for Canines and Felines? | Generally: 12 for Canines, 8 for Felines |
| What is the parallel technique used for in dental radiography? | To obtain images of the mandibular 4th premolars and molars in dogs and cats |
| How would you correct a dental image that appears foreshortened? | Decrease the bisecting angle by redirecting the tube head toward the patient. |
| How would you correct a dental image that appears elongated? | Increase the bisecting angle by redirecting the tube head toward the sensor. |
| If additional magnification of small patients is desired, you should: | Increase the object-film distance |
| If the alveolar bone isn't visible on a dental radiograph, then you should: | Move the sensor laterally |
| What is the special x-ray tube placement for the ventrodorsal cervical spine and why is it necessary? | Angled slightly toward the head of the animal so the x-ray beam can pass cleanly through the space between the vertebrae. |
| When positioning an animal for a craniocaudal humerus view, a common problem is that the: | Humerus usually looks somewhat magnified |
| What is proper positioning for a Rostrocaudal Foramen Magnum projection? | Dorsal recumbency, forelimbs secured caudally, foam/sandbag under neck, tilt nose approx. 30 degrees with mandible close to chest. |
| To determine if a lateral skull view is truly lateral or not, the ______should be superimposed | Top and bottom canine teeth |
| When radiographing the thorax, where should the positioning sponges be placed to prevent rotation? | Under the elbows and ventral abdomen |
| When positioning for the caudocranial view of a tibia, the ____side of the animal should be closest to the table | Ventral |
| When should a left marker be used? | When a ventrodorsal pelvis radiograph is being taken or a left limb is being radiographed |
| For a radiograph of soft tissue such as the pharynx, how should the x-ray machine settings be changed from the settings for the cervical spine? | The kV should be increased, the mAs decreased |
| When performing a dorsoplantar radiograph of an equine hoof, what special piece of positioning equipment is used for this view and why? | Tube tilted downward, cassette placed under hoof. All equine radiographs are taken in standing position. The cassette needs to be placed in a tunnel so that it is not damaged under the weight of the horse. |
| An evaluation of the navicular bone of an equine includes what views? | Dorsopalmar/dorsoplantar view (65 degrees), flexor view, Oblique view |
| An evaluation of a carpus of a horse includes what views? | Dorsopalmar/lateral, medial oblique, lateral oblique, flexed, skyline |
| Even though avian patients can be restrained with tape directly to a cassette, what method is more highly recommended and why? | Tape the bird to a Plexiglass sheet rather than the cassette to allow the bird to be moved from one cassette to another without having to untape each time |
| A cervical spine study of an equine requires collimation centered: | On the ventral part of the neck, in a lateral view |
| Computed tomography is not useful for imaging which body part? | The abdomen of a horse |
| What would be the best type of equipment and settings to use for optimal radiographs of birds or lizards? | High mA, low kVp, rare earth screen |
| Define echogenicity: | How well a certain tissue type reflects sound waves |
| What is a concern when attempting to ultrasound the GI area? | The concern is gas or air which is reflective and doesn't allow for proper visualization of the structures around it |
| When fractures are suspected in the hips, the __________ view is often used for initial evaluation. | Frogleg view: dorsal recumbency with thorax in V-trough, femurs at 45 degrees to the spine (large dogs 90 degrees). Center between ischial tuberosities. |
| What do you look at when evaluating a film to see if the ventrodorsal abdominal radiograph is truly ventrodorsal? | Dorsal ventral processes |
| According to the bone rule of collimating radiographs, how should the beam be centered? | Over the caudal joint and should include one inch of bone on either side. |
| The thoracic girdle is also referred to as the: | Shoulder area (including scapulae and clavicle. |
| Minimally, what 2 views are taken of every area radiographed? | Lateral view and ventrodorsal (VD) view |
| Generally speaking, the most common error in taking an abdominal radiograph is that the shot is too: | Caudal and doesn't include the liver |
| You're taking a radiograph of a spaniel's abdomen. It's best to put the animal in which position(s)? | Right lateral or Dorsal recumbency |
| When radiographing the pelvis in a lateral position the _____ should be included in the view | Entire femur |
| Which radiographic view of a horse requires general anesthesia? | Ventrodorsal view of the pelvis |
| What is generally the ideal focal-film distance when radiographing exotic companion animals? | 40 inches |
| Where should a Bird be measured for the lateral and VD radiographs? | Mid-sternum at the thickest part of the chest |
| For small mammals, a chest film is taken with the primary beam centered on the: | Xiphoid process |
| What does PID stand for? | Position indicating device |
| How many views are normally required when radiographing an equine joint? | 6 views |
| Which bone in horses only requires three views to be taken? | Navicular bone |
| The vasovagal response is induced in lizards by gentle digital pressure applied to the: | Orbits |
| Incisors generally require an angle of ______ degrees to produce a good quality dental radiograph. | 60 degrees |
| To take a lateral proximal phalanx (P1) in a horse, you should position the beam at what angle to the ground? | Parallel |
| Technique is the term used to describe: | All factors that are set on the machine |
| What are the 3 methods of radiation protection? | Distance, shielding, & time |
| Radiographic envelopes generally do not contain what information? | kVp and mA settings |
| What is the best way to remove hair and dust from an intensifying screen? | Dampen a gauze pad with cleaning solution and wipe the surface carefully. |
| The purpose of a rectifier is to: | Convert direct current to alternating current (DC to AC) |
| After placing the film into the tank for developing, you should: | Gently move the film up and down to remove air bubbles |
| When should you refill a film cassette? | Immediately after you place the film into the water tank |
| What material absorbs the most x-rays? | Bone |
| If a radiograph has a dark background, and the bones are relatively bright, for the next radiograph you should: | Decrease the mAs |
| According to the inverse square law, if you double the subject's distance from the X-ray tube, the X-ray exposure is: | Cut to one quarter (1/4) |
| An automatic processor takes less time to process film than hand developing because: | It uses special chemicals and a higher developing temperature |
| Why is it important to keep the darkroom counter tops clean? | When a film box is opened, it creates a vacuum that can draw in dirt and debris |
| If the 'S' setting is correct what is true about an image taken at 70 kVp as compared to one taken at 50 kVp? | At 70 kV there's an increased radiographic density and decreased radiographic contrast |
| A higher kVp will result in: | dense, darker images |
| What component of the fixer decreases the time needed for drying a developed film? | Hardener |
| A special film must be used with an intensifying screen using rare-earth phosphorus because the: | Crystals emit light in the green spectrum, which silver halide film won't absorb |
| Along with solvent and preservatives, fixer contains: | a fixing agent, acidifier and hardener |
| Why would you perform a survey radiograph before a GI series? | To ensure that a previously administered enema worked properly |
| In what situation would barium be contradicted as a first line contrast agent? | If there's suspected intestinal perforation |
| Computed tomography is useful for imaging which body part of a feline? | The Spine |
| In ultrasound, _____ wave lengths produce greater resolution. | shorter wave lengths |
| Name two functions of the adjustable collimator seen on most stationary small-animal machines: | To limit the area covered by the primary beam; to reduce scatter radiation |
| What is the minimal radiation safety protection necessary when in the room during the x-ray exposure? | Lead gown, lead gloves with 0.5mm lead equivalent, thyroid protector |
| What is the purpose of a rotating anode? | To dissipate heat more quickly and prevent damage to the anode. |
| What determines the amount of absorption of the x-rays as they pass through an object? | The atomic number of the material, the physical density of the object, and the energy of the x-rays |
| What is the difference between primary and scatter radiation? | Primary = found in x-ray beam leaving machine and makes the image on the film. Scatter = radiation that bounces off the target and is harmful to others in room at time of exposure |
| What is the purpose of the aluminum filter, located between the x-ray tube and the collimator? | Eliminates the soft x-ray, which causes skin damage. |
| Why is it important in veterinary radiology to keep the mA setting as high as possible? | Exposure time can be lower. Since motion is the main artifact in vet med, shortened time = less chance of motion from the animal. Also reduces radiation exposure. |
| List three functions of a cassette: | hold the intensifying screens, keep the film clean, and keep light away from the film. |
| What is a latent image? | Image on film once the film is exposed to radiation, but cannot be seen because film development hasn't yet occurred. |
| When storing film, what three factors must be considered? | The film storage must be light-tight, dry, and cool. Free from radiation; no fumes from chemicals in sufficient amounts to be a detriment to the film. |
| What is the most common cause of x-ray tube failure? | Filament evaporation |
| Where is the grid located and what is its purpose? | Under the table; above the cassette holding tray. Prevents scatter radiation from reaching the film when cassette is placed in the holding tray. |
| What is the difference between nonscreen film and regular film? Discuss appearance and function: | Screen film: placed in cassette for use; sensitive to light which produces the image via intensifying screens. Nonscreen: placed in lighttight paper envelope; sensitive to x-rays which produce the image vs. light. Higher detail, requires more radiation |
| When does reticulation of the film occur? | During the developing process when film is moved from a chemical of one temperature to another at a different temperature. The change causes reticulation. Keeping all at same temp prevents reticulation. |
| What are the steps in the manual film processing procedure? | Developer; wash; fixer; wash; dry |
| When developing, films should spend twice as long in the ____ as in the _____ | fixer; developer |
| List three possible causes in the radiology room for a light radiograph: | Not enough radiation; tube is too far away from the cassette; cassette was placed in the tray when it should have been placed on the tabletop. |
| List two possible causes in the darkroom for a dark radiograph: | Overdeveloped (too long in the developer solution); fog due to improper lighting or light leak. |
| Why is it necessary to check the collimator light against the x-ray beam? | The light mechanism is located in the collimator, but isn't the same mechanism that controls the size of the beam. If they don't align, you might expose a different area than the light is indicating. |
| For most vet clinic technique charts, exposure time usually needs to be ____ when a grid is used. | Doubled |
| Which skull view requires the x-ray tube to be tilted? Why is this a requirements for this view? | Open-mouth nasal view (ventrodorsal). Helps prevent the mandible from superimposing over the nasal area and therefore rendering the radiograph useless for this area |
| Name two ways the tympanic bullae can be evaluated. Give the positioning for each. | Lateral position- head is rotated to the affected side Open-mouth tympanic bullae-dorsal recumbency, nose is pointed to ceiling, lower jaw slightly opened and beam centered into back of mouth |
| When radiographing the spine of an animal, there are four "points" that we use for landmarks. What are they? | Base of skull, shoulder, where last rib meets spine, the greater trochanter of the femur |
| Name several contrast agents that are commonly used in veterinary radiography. | Barium sulfate, iodine preparations, oxygen, carbon dioxide, nitrogen, and nitrous oxide |
| Describe the steps required for taking a dorsoventral view of a turtle: | Turtle on back, flip ventrally right before exposure but wait for legs and head to be extended then take radiograph |
| What is the concept behind ultrasound images? | a transducer placed against the skin emits sound waves into patient; different tissues reflect different amounts of the waves and the information is fed to computer for evaluation |
| What angle is used for obtaining the image of the premolars and molars with a feline patient in sternal recumbency? | 35 degrees |
| What angle is used for obtaining the image of the fourth premolar in a canine patient placed in sternal recumbency? | 45 degrees |
| What is the proper collimation for the small mammal lateral view of the abdomen? | Cranial to the xyphoid and caudal to the pubis |
| What is the proper collimation for the small mammal lateral view of the thorax? | Cranial to thoracic inlet and caudal to last rib |
| What are two common errors that occur in dental radiography? | Elongation and foreshortening of the teeth |
| What are the two techniques used in dental imaging? | Parallel and bisecting angle techniques |
| Describe the basic idea of how an x-ray tube works: | Electrons generated at cathode by filament. Voltage passed between cathode & anode. Electrons pass from cathode to anode an colide with target. X-rays are then directed down towards patient. |
| How is the electromagnetic spectrum measured? | Energy (eV), frequency (Hz), and wavelength (l) |
| Why are short wavelengths better than long wavelengths for radiograph production? | They’re more powerful; higher potential for penetration through mass. |
| Define milliamperage (mA): | The number/quantity of x-rays that will be emitted from the machine. Higher amount = darker image. |
| What affects the film speed? What are the film speed ratings? | The size of the silver halide crystals. Ratings = high-speed (fast), average (par), slow (detailed). |
| Define Object Film Distance (OFD): | The distance from the object being radiographed to the cassette. |
| What are the 4 technique charts normally kept for the x-ray machine? | Thorax, abdomen, pelvis/spine, extremities |
| What is the density order of tissues from low to high? | Gas > fat > water > bone |
| What four areas are evaluated on a completed radiograph to decide if it’s high quality? | Film contrast, density of the image, proper positioning, and labeling. |
| How do you try to remove image noise? | since noise is directly inverse to image contrast, use higher mAs or kVp to minimize noise |
| What type of cassette screen is used in computed radiography (CR)? | A screen composed of photostimulable phosphors |
| What needs to be done prior to a contrast study? | Animal fasted 8-24hrs; enema if applicable. Perform early so gas doesn't build up and obscure the image. Take a survey radiograph. before admin of contrast. |
| List three types of transducers: | Sector, linear, curvilinear, phased, and annular arrays |
| What is the difference between Positioning and Landmarks? | Positioning: the way the animal looks when lying on the table. Landmarks: part of the animal you use to determine whether or not you are including entire body part in radiograph |
| What does OFA stand for? | Orthopaedic Foundation for Animals |
| What does CHD stand for? | Canine Hip Displasia |
| What do the PennHIP radiographs evaluate? | Distraction index, arthritis, and breed laxity profile ranking |
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