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Core radiation
| Question | Answer |
|---|---|
| What does the silver recovery system do? | Filters silver from going down the drain |
| Which of the following removes unused chemistry on the films before they are used? | Water |
| What chemical in the film processor dissolves unexposed silver ions and makes a permanent image? | Fixer |
| Which chemical in the film processor is a reducing agent that produces shades of gray? | Developer |
| What is the route the film takes through an automatic processor? | Developer to fixer to wash to dry. |
| What type of filter must be used in the Safelite? | An amber filter specifically made for X-ray dark rooms |
| What wattage bulb is recommended in the Safelite | 15 watt |
| What distance must safelights be mounted from the workbench? | 3 ft away |
| Important to remember this order | Developer to fixer to wash to dry |
| What happens to the silver ions in the developer? | The developer reduces silver ions to black metallic silver |
| What happens if the developer is too warm | The image will be overexposed |
| What does the fixer do? | Removes unused silver ions and makes the image permanent. |
| Increasing window level on the monitor does what to the image ? | Darkens the image |
| Short scale | Lower kVp higher contrast More contrast Less shades of gray |
| What is scatter | Interaction of X-ray beams and atoms of a patient X-ray beam enters patient, deviates direction and leaves the patient |
| What are TLDs | Thermoluminescent dosimeter |
| Two common dosimeters | Film badges Thermoluminescent dosimeter |
| What is the actual numbers of electrons caused by? | mA |
| What is the purpose of the grid? | To reduce scatter (Therefore increasing contrast) |
| What controls wavelength | KVp (quality and penetrability) |
| Where does the main source of scatter come from? | The patient |
| What reduces visibility of anatomy and causes fog? | Scatter |
| What absorbs more radiation and has the least amount of scatter? | Bones ( bones appear white on image) |
| What does the CR reader use to cause the latent image to become manifest? | A laser |
| Why do we collimate to the area of interest? | Reduces scatter Reduces patient dose Increase contrast |
| What type of body part gets more scatter (thick/thin) | Thick |
| Long scale | Higher kVP lower contrast Lower contrast More shades of gray |
| What is frequency? | How many wavelengths pass in a given per sec. |
| The higher the atomic number ... | ... the denser the anatomy ( image appears bright and white) |
| What will NOT cause the grid cutoff? | Angling along grid lines |
| A completely accurated digital system will have what? | A MTF ( module transfer function) Measures how efficiently signal is transferred to computer. |
| What is the moiré effect? | Zebra pattern caused by grid lines |
| What does latent mean? | Invisible |
| What controls contrast? | kVp |
| What is the anode heel effect? | When the cathode end is more intense |
| What reduces scatter? | The grid |
| What is the purpose of the compensating filter? | To offset tissue thickness Provides uniform density on the image |
| What is the attenuation order highest to lowest? | Bone/teeth Muscle Organs Epitheal (skin) Fat Gas |
| Where is the step down transformer located? | The filament circuit |
| Four steps in exposure field recognition | Number of pixels sampled Needs to detect collimated edges Histogram creation Great scale rendition |
| HVL can be used Interchangeably with ...? | Filtration |
| What is spacial resolution? | Recorded image and sharpness of image |
| What is the primary purpose of total filtration? | Reduces patient skin dose (Hardens the beam) |
| What is the range of exposure values to the image that will produce an acceptable range of densities for diagnostic purposes? | Exposure latitude |
| What is direct image? | Image immediately turned into electronic signals (no light) |
| What is another term for CR reader? | Plate reader |
| What is another name for quantum model? | Quantum noise |
| What is PACS/ what does it do? | Storage for images (on a server) Archives, stores, distributes and display images |
| What does indirect mean? | When there is light |
| Edge enhancement increases what? | Contrast on the edge of a structure |
| What is CMOS? | Converts light to electrons |
| What is bit depth? | Number of bits per pixel |
| What is DICOM? | Standard exchange of computer data. |
| Why must PA scoliosis exam be PA? | To lower dose to the anterior body protecting patients thyroid and breast specifically. |
| What is a specialized cell? | Mature cell. |
| How thick must lead aprons be? | 0.50 mm Pb eq. |
| What is LET? | Linear energy transfer |
| What is an example of a carcinogenic effect? | Thyroid cancer that is radiation induced |
| What happens to patient dose when collimation size is increased? | Patient dose is increased |
| What absorbs x-ray the most? | Bones |
| Threshold meaning: | There is a safe amount of radiation with no observable effects Non-linear dose response |
| What does milliamperage control? | Patient dose |
| What is meosis? | REPRODUCTIVE cell division (sperm and eggs) |
| What is occupational dose? | Any radiation received on the job |
| Is medical dose related to occupational dose? | No |
| What does ARS stand for? | Acute radiation syndrome |
| What is Bremsstrahlung radiation? | Breaking radiation Interaction b/w filament electron and target nucleus |
| What is grid ratio? | Height of lead strips versus distance between them |
| Where is the central ray for the mortise view? | Central Ray is mid ankle |
| Where is the central Ray for AP toes? | CR 15 degrees cephalic on 3rd MTP |
| What is the tarsal that is inferior to the talus? | The calcaneus |
| Stretcher: How much is it angled? Where is the central ray? | Cassette or tube angled 20° Central ray on scaphoid to elongate bone |
| What is the positioning for camp Coventry? | Patient prone Tube angled 40 to 50° Knee flexed 40° Demonstrates intercondylar fossa and tibial spine |
| What is differential absorption? | Different tissues absorb x-ray at different rates |
| What is the prominence of the proximal lateral femur | The greater trochanter |
| What type of bones are tarsals? | Short bones |
| What does atomic number affect? | Effects beam attenuation High atomic number equals high beam attenuation |
| What is the KVP selector? | Auto transformer Can increase or decrease voltage by a pre-determined amount |
| Relative biologic effect (RBE) is directly related to what? | LET (when LET goes up, RBE goes up) |
| What does the capitulum articulate way? | The Radial head |
| Where is the head of the radius located? | The elbow |
| Where is the head of the ulna located? | The wrist |
| Sampling frequency is associated with what? | Pixel density (bit depth) Spacial resolution |
| What does windowing refer to? | Contrast resolution |
| What does contrast resolution? | The systems ability to differentiate between the shades of gray |
| What does KVP control? | Penetrability of the beam |
| Which digital system is hardwired into the computer | DR ( direct radiography) |
| What is the removal or addition of an electron to a stable atom? | Ionization |
| Which factor is related to the x-ray current? | mAs |
| The quantity of x-ray photons exposing the patient is primarily controlled by? | mAs |
| How are mAs and optical density related during image formation? | mAs.and density are directly proportional |
| Why is the 15% rule for KVP used? | To double or cut in half the density of an image |
| What is the hand position for the lateral elbow? | Hand is lateral |
| What are the topographical landmarks of the elbow? | The humeral epicondyles |
| What does the MCP joint connect? | MCP joint joins the fingers to the hand |
| Hand Where is the central Ray? How many degrees is the oblique? | Central ray is on 3rd MCP joint Oblique 45° |
| What are the only short bones in the body? | Carpals and tarsals |
| Where does the central ray go on digits two through five | PIP ( Proximal inter phalanges joint ) |
| When are the epicondyles perpendicular? When are they parallel? | Perpendicular: lateral humerus position Parallel: AP |
| What is the hand position for an AP forearm? | Hand is supinated |
| Wrist: why does hand need to be flexed? | To move wrist carpal’s closer to the IR |
| What position are the epicondyles for lateral forearm? | Epicondyles are superimposed (stacked) |
| What do you do if a patient cannot flex their elbow? | Do a partial flexion view |
| What’s another name for spongy bone? | Cancellous bone |
| What does the pre-set timer control? | Length of x-ray exposure |
| What does MA control? | Patient dose |
| What is SID? | Source to image receptor distance Distance between tube an image receptor |
| What does the lateral rotation of the elbow show? | The ulna |
| What is the atomic number of an Atom determined by? | Protons |
| What does the flat panel detector replace in the x-ray table? | Bucky assembly |
| What does the rectifier do? | Change is alternating current AC to direct current DC Allows current to flow in one direction |
| What is photo electric affect? | Inner shell electrons X-ray interaction where total absorption takes place during ionization of an inner shell electrons stopping the x-ray in the body Also cascading effect |
| What does osgood-schlatter disease effect? What position best demonstrate this? | Effects tuberosity Knee series |
| What row is used for KVP? | 15% rule |
| What is our ROI ( region of interest) ? | Characterizes pathology In an AOI by using a quantative function that allows for the pixel values to be analyzed ( if an area is solid or fluid) |
| Where is the central ray for the medial lateral lateral knee? And how much is the knee flexed? | CR 1 inch distal to medial epicondyles 5 to 7° cephallad Knee flexed 20 to 30° |
| What is shown during medial rotation of the oblique elbow? | Coronoid process is shown |
| Ulnar deviation (ulnar flexion) How is the tube angled? What does it demonstrate? | Tube angle 10 to 15° Demonstrate scaphoid and elongates bone |
| How many degrees is the oblique foot? | 30 to 45° medially |
| What tarsal is anterior and medial to the talus? | Navicular |
| Where is the central ray for an AP fly? | Central Ray is angled 10° cephalad towards third MTP base. |
| How many degrees oblique for the mortise view? | 20° oblique ankle |
| What makes up the lower leg? What’s lateral? What’s medial? | Tibia and Fibula Fibula is lateral Tibia is medial |
| Where is the central ray for a lateral foot? | CR is perpendicular to the base of the third metatarsal |
| Occupation does per year? Body Skin/extremities Eye | Whole body 5 rem Skin/ extremity 50 rem Eye 5 rem |
| AP knee angle for patient 18 cm and below? | 5° caudad |
| Where is the central ray when performing a medial lateral, lateral position on the ankle? | Central ray is on the medial malleolus |
| What touches IR during an AP foot? | Plantar surface touches the IR |
| Inverse square law | Decrease SID equals more intense Increase SID equals less intense ( always by factor of 4 ) |
| Attenuation is a part of what? | Absorption ( Photo electric effect ) Scatter ( Compton effect ) |
| What states the effective focal spot is smaller than actual focal spot? | Lone focus principle |
| What would be changed if a reduction in the exposure time is needed: maintaining the same optical density on the image? | Use of a higher MA |
| What is the proximal posterior rounded structure of the elbow called? | Olecranon process |
| What is another name for Gaynor-heart method? What angle is the central ray? | Carpal canal Angled 25 to 30° |
| What is the LUT ( look up table ) | Software that changes contrast and brightness of the image Determines the numbers assigned to the input pixel values and changes output pixel values |
| AP knee tube angle for patient 25 cm and above? | 5° cephalad |
| What does mAs control? | Patient dose Quantity of photons Brightness ( density ) |
| What are the landmarks of the wrist? | Styloids |
| The reduction in x-ray photon intensity as it passes through matter is? | Attenuation |
| What is the main articulations surface of the distal humorous? | Trochlea |
| What is found inside the digital imaging receptor? | Photostimulable phosphor imaging plate |
| What position is the hand in for the couple method? | Hand is pronated |
| How do you double the optical density using the kVp? | Increase the kVp by 15% |
| When mA is doubled what happens to the optical density? | Increases |
| What does it mean when a wavelength is shorter? | The beam has more energy |
| What does kVp control? | Energy of the beam and wavelength of the beam |
| How is the intensity of the beam effected, as the tube distance is lowered toward the IR? | Increases |
| What does the “kilo” in kilovolts represent? | 1,000 times more volts |
| As the tube distance is lowered to the IR the intensity of the beam will be effected by a factor of? | 4x greater |
| What is the definition of bremsstrahlung radiation? | Braking radiation |
| Transformers: | Increases voltage - step up Decreases voltage - stem down |
| What is the range of exposure intensities that an image receptor can respond to and acquire image data? | Dynamic range |
| kVp : | Quality Kinetic energy |
| What causes a ghost image | Erasure too short Scatter from other images Burnt out erasure lamp |
| What two things do you multiply together to get mAs ? | Milliamperage and time |
| What is HIS? | Hospital information system |
| Inadequate mAs will increase quantum model, How is this fixed? | By upping the mAs |
| What happens to electrons the higher the kVp | The higher the kVp, the faster the electrons move across the tube |
| What is RIS? | Radiology information system |
| What is frequency? | How many wavelengths go through a given point * the higher the kVp, the higher the frequency |
| What is Roentgen | Ionization of air |
| What happens to images in digital radiography | Images start to degrade immediately |
| Where is DEL? ( detect or element) | Only in FPD in both direct and indirect |
| mAs | Quantity Current 0 energy |
| What does Rad stand for? | Radiation absorbed dose |
| X-ray tube energy | 99% heat 1% X-ray |
| What is Compton effect? | Outer shell electron interaction with X-ray X-ray interacts with patient, attenuates, changes directions and leaves patient body at a lower energy value as when it entered. |
| What is amps? | How we measure current Unit of electrical current |
| What is the unit of measure when calibrating display monitors? | |
| Candela ( measures luminance) | |
| What causes fog on the image? | Compton effect |
| What is erythema ? | Reddening of the skin |
| What does manifest mean? | Visible |
| What is RIS and HIS used for? | Computer networking – how textual info is shared |
| What aspect of the x-ray beam is the kilovoltage responsible for? | Quality of radiation |
| The optical density is decreased by changing the SID: what can be done to the technical factors to compensate for the distance change using new mAs formula | Increase the mAs by four times |
| More signal and what makes good? | Less noise |
| What setting will produce the most optical density? | The higher the KVP the greater the density |
| Two types of radiation | Bremsstrahlung characteristic |
| What does indirect use to convert light to know electrical signal? | CCD, CMOS, or TFT |
| What is grid ratio? | Focusing distance ( focused grid) |
| What does the exposure indicator number measure? | How much radiation was absorbed by the IP (image plate) or FPD |
| What is MPD ( maximum perssible dose) for pregnant X-ray techs? | 500 mrem (0.5 rem ) per 9 months |
| What happens when lethal dose is reached? | LD 50/30 (50% of the population will die in 30 days) |
| Law of conservation of energy states .... | Power output can be no greater than power input |
| What is primary beam? | X-ray beam that exits collimator and exposes the patient |
| What is the source of electrons in the tube? | Filament wire |
| What circle the nucleus of an atom | Electrons |
| Where does electrical potential in the X-ray tube come from? | Voltage ( kinetic energy) |
| What is remnant radiation? | Also known as residual beam exit transmitted The remaining beam after attenuated radiation leaves the body This forms the image |
| High current applied to the filament wire causes what? | Thermionic emission |
| What provides a vacuum inside the tube? | Glass envelope |
| What is characteristic radiation | When an outer shell electron fills an inner shell void Cascading effect |
| What is the measure of resistance? | Ohm |
| What are the most radio resistant cells ( least radio sensitive) | Muscle cells Nerve cells ( neurons) |
| What does Compton cause? | Scatter and secondary radiation |
| What does rem stand for? | Radiation equivalent man ( biological dose) |
Created by:
Waltguzman
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