Reviewer in RT Chapter 9-13 PDF

CHAPTER 9 - The depth of the filament in the cathode cup slot. Where do cathode cups are typically It is a device for generating x-rays by manufactured from? accel...

CHAPTER 9 - The depth of the filament in the cathode cup slot. Where do cathode cups are typically It is a device for generating x-rays by manufactured from? accelerating electrons to a high energy by an electrostatic field. - Molybdenum, nickel or an iron alloy - X-ray tube It is connected to a common lead for It is produced by heating the cathode by both filament is supplied with a lower means of white-hot tungsten filament. than operating current to heat the - Electron beam filament. What supplies the high voltage, often - High Tension 100 kV? It limits the number of electrons - Transformer produced at the filament, thereby limiting the maximum tube current Fact: possible. 1. On the half-cycles when the target - Electrostatic field is negative nothing happens. 2. When the target becomes positive, Fact: the electrons bombarding it 1. As the tube voltage increases, the generate x-rays. tube current increases up to a What are the two main parts of an x-ray point when all the electrons in tube? the space charge have been used up and the tube is then said to have - Cathode reached saturation current. - Anode This effect happens as more and kore It consists of the filaments, focusing electrons build up in the area of the cup, and associated wiring. filament, their negative charges begin to oppose the emission of additional - Cathode assembly electrons. A small coil of thin thoriated tungsten - Space charge effect wire. It is where the electrons for the production of x-rays are emitted. This effect happens as kVp increases; a greater percentage of the thermionically - Filament emitted electrons are driven toward the It is set centrally in a slot machined anode. into a metal focusing cup. - Saturation current - Filament This assembly consists of the anode, What is the focusing cup being referred stator, and rotor. to in aforementioned? - Anode assembly - Cathode cup It is a positively charged so that Fact: electrons from the filament (cathode) are attracted to it to produce x-rays. 1. The shape of the cup, along with electrostatic forces, prevents the - Anode assembly electron beam fanning out. It is the stationary part of an electric 2. The design is called an electronic motor or alternator. This consist of lens system with a resulting focal series of electromagnets equally spaced spot width that depends upon: around the neck of the tube. - The diameter of the filament helix - The length of the filament helix - Stator - The width of the cathode cup slot It is the non-stationary part of a It is the physical area of the focal rotary electric motor or alternator, track that is impacted. which rotates because the wires and - Actual focal spot magnetic field of the motor are arranged so that a torque is developed about the It is the portion of the anode where the rotor’s axis. high voltage electron stream will impact. - Rotor - Focal track Facts about anode: It is the area of the focal spot that is 1. It serves as a target surface for projected out of the tube toward the the high voltage electrons. object being radiographed. 2. Conducts the high voltage from the cathode back into the x-ray - Effective focal spot generator circuit. 3. Served as the primary thermal It is one way to control the size of the conductor. effective focal spot. An anode assembly that is immobile. - Angle of the focal spot - Stationary anode It is used to produce the effective area of the focal spot. An anode assembly that turns during exposure. - Line-focus principle - Rotating anode The effective focal spot size is controlled by what? Facts: - Size of the actual focal spot and 1. Proton (atomic) number 74 - The the anode target angle. higher the proton number of the target the grater the amount of It is the one that is stated as the the target the greater the amount focal spot size. of the radiation that will be - The effective focal spot’s produced for a given tube voltage vertical dimension and current. 2. High melting point - Tungsten’s This effect is due to the geometry of melting point of around 3400 the angled anode target, the radiation degrees celsius means it can intensity is greater on the cathode withstand the high temperatures side. involved without melting and with little distortion. - Anode heel effect 3. Electrical conductivity - The Fact: anode is required to conduct the tube current. 1. When an anode stops turning, the 4. Thermal conductivity- The target anode actually melts. needs to dissipate the large It is the glass housing that protects amounts of heat produced. the tube. It is also used to help protect from excessive exposure to x- rays. It is used for soft tissue imaging. - Envelope - Molybdenum (42) It is also the first part of the The target, focus, focal point, focal filtration system. spot means the same thing. (T/F) - Envelope - True This is where the high voltage electrons hit the anode. - Target area It is the removal of the air permits It permits the calculation of the time electron to flow from cathode to anode necessary for the anode to cool enough without encountering the gas atoms. for the additional exposure to be taken. - Vacuum - Anode cooling charts It controls the leakage and scattered radiation, isolates the high voltages, CHAPTER 10 and provides a means to cool the tube. - Protective housing These are produced in the target of the It is any photons that escape from the anode when high energy projectiles housing except at the port. And it must electrons are rapidly decelerated. not exceed 100 mR/hr at 1 meter. - Diagnostic x-rays - Leakage radiation This also provides the means for These are photos that were not produced practitioner to control the quality and at the focal spot or extrafocal quantity of the x-ray beam. radiation. - Diagnostic x-rays - Off-focus radiation In x-ray tube, its purpose is to provide It is a guide regarding the most common technical factor combinations that can the free electrons necessary for x-ray production. be used without overloading the tube. - Filament - Radiographic tube rating chart (RTRC) This process happens when the rotor is activated the current passing through What are the three min types of heat the filament heats to the point where generation in an x-ray tube. electrons boil off. - Convection - Thermionic emission - Conduction - Radiation What is the potential energy for each electron? It is the transfer if thermal energy by actual physical movement from one - One kiloelectron volt (keV) of location to another of a substance in energy for each kilovolt (kV) which thermal energy is stored. They are sometimes called projectile - Convection electrons that travel from the cathode to anode make up the tube current. It is the flow of thermal energy through a substance from a higher-to a lower- - Electrons temperature region. This is from the stator axel to the anode. Fact: - Conduction 1. Approximately 99% of the energy of the projectile electrons converts It is the energy radiated by solids, into heat. Only about 1% of the liquids, and gases in the form of energy converts into x-ray electromagnetic waves as a result of photons. their temperature. This occurs when projectile electrons - Radiation (also known as thermal pass by the outer shell of target atoms radiation) and interact with the force field of the nucleus of the atom. This occurs when the electron hit the anode target and heat up the anode. - Bremsstrahlung radiation - Radiation It is a continuous radiation. - Bremsstrahlung radiation The loss of kinetic energy that occurs What is the maximum photon energy that when a projectile electron slows down is is determined by the maximum voltage? emitted as an? - Kilovolt peak (kVp) - X-ray photon Example: In the diagnostic range, approximately 1. If the potential difference across how many percentages of x-ray emissions the tube were 90 kVp, an electron are the result of bremsstrahlung accelerated across the tube would interactions? attain a kinetic energy of 90 keV - 85% as it interacted with the target. It is produced when projectile electrons Is the maximum photon energy dependent with sufficient kinetic energy eject an on the potential difference across the inner orbital electron. tube (kVp), regardless of the target material? - Characteristic radiation - Yes When was the x-ray bombardment of pure elements first observed? And by who? It reflects the quality and quantity of the x-ray beam. - 1909 - Charles G. Barkla and C.A. Sadler - The size and shape of the emission spectrum It is essential to have at least one filament for x-ray production. Where do ranges located more which represents the x-ray beams of higher - Cathode energy or quality? The shape of the focusing cup and its - More towards the right negative electric charge cause the electrons to be repelled in the Graphically, the area under the curve direction of a very precise area on the represents what? target called? - Total number of x-rays emitted - Focal spot The greatest number of x-rays have This energy conversion takes place at approximately one-third to one-half of the target. And constructed to dissipate the maximum energy. (T/F) heat. - True - Anode It is referred to as discrete or Modern tubes for radiography have a distinct spectrum. (blank) anode? - Spectrum produced by - Rotating anode, which is in the characteristics x-rays form of a disk with a beveled-edge What is the 5th energy level of target. characteristic x-ray from tungsten? It is a graphic representation of the - Interactions at the K shell number of x-rays plotted against the energy of the radiation, which is What is the 4th energy level of measured in kiloelectron volts (keV). characteristic x-ray from tungsten? - Emission spectrum - Interactions at the L shell It is the difference between the *The remainder are from the interactions entering and exiting kinetic energy of at the lower energy outer shell. the projectile electron. In tungsten, only what characteristic x- - Energy of a bremsstrahlung rays are considered sufficient energy to be of diagnostic value? - From five K shell interactions Is the number of photons produced at - Distance each characteristic energy level - kVp different? - mAs - Yes, because the likelihood for It changes the characteristics of the filling a K shell void varies from beam by removing ineffective low energy shell to shell. x-rays. Often, the five energy levels are - Beam filtration represented on what? When a radiologist inherent and added - Emission spectrum of a single line filtration that reduces the quantity and increases the average energy of the x- What is the quality of radiation in an ray beam, what will happen to patient’s x-ray beam? skin? - The penetrating ability of the - Reduced patient skin dose beam It affects the quantity of x-ray What is the quantity of radiation in an photons, where the inverse square law x-ray beam? governe the relationship between the - The number of photons in the beam quantity if x-ray photons and the dustance from the target of the image What are the basic factors influencing receptor. the quality and quantity of the x-ray beam? - Distance - Target material What does SID stand for? - Beam filtration - Source-image distance - Distance - Prime exposure factors Fact: These affects the quality and quantity 1. The quantity of x-ray photons at if the x-ray beam. the image receptor is inversely proportional to the square of the - The target material and beam distance from the source. filtration 2. For example, if the SID is reduced Can practitioners control distance and by one half, the number of x-ray prime factors? photons quadruples. - Yes What are the two prime exposure factors? Can practitioners the selection of the - kVp target material and limited options? - mA exposure time - Little or no It affects both quality and quantity. It affects both quality and quantity of - kVp the x-ray beam. It affects only the quantity of the x- - The photon number of the target ray beam. material - mA exposure time What are the factors affecting x-ray It determines the voltage or potential quality? difference applied across the cathode - Target material and anode during the exposure. - Beam filtration - Kilovoltage peak (kvP) - KVp This controls the speed of electrons What are the factors affecting x-ray traveling from the cathode and anode. quantity? - Kilovoltage setting - Target material - Beam filtration Fact: It is controlled through a separate circuit called the Filament circuit. 1. The maximum energy of an x-ray beam remains equal to the kVP - Tube current settiny. It is provided by taps of the It determines the quantity if electrons autotransformer. in the tube current. - Voltage - Milliamperage (mA) and expaure The tube current is usally not time continuously variable, usually how many It is the product of mA and exposure currents are provided? time. - 50, 100, 150, 200, and 300 mA and - Milliampere-second higher When the autotransformer lowers the voltage, what is it called? CHAPTER 11 - Step down transformer Fact: It is the part of Thank you machine that the operator controls the operation of 1. For any given radiographic the x-ray machine. examination, the number of x-rays reaching the image receptor is - X-ray imaging system directly related to the tube Fact: current and time that the tube is energized. 1. All machine consoles are a little different but the are always Is the timer circuit separate from the similarities. other circuits? It is where we control x-ray tube - Yes current and voltage. It consists of a mechanical or - Console electronic device whose action is to make and break the high voltage across The console will have controls for. the tube on the primary side of the high voltage. - mA and time or mAs - kVp - Exposure timers - Focal spot - Line voltage compensation What are the types of timers? - Automatic exposure control - Mechanical timers It is designed to supply voltage of - Synchronous timers varying magnitude to several different - Electronic timers circuits of the x-ray machine. - mAs timers - Phototimers - Autotransformer It is a very simple device that has a How many windings and core does the clock mechanism. It can be used for autotransformer have? exposure time longer than 250 milliseconds. - One - Mechanical timers The tube current, the number of electrons crossing from the cathode to It is a very old machine and dental anode per second is measured in what? units. - Milliamperes (mA) - Mechanical timer It is the most sophisticated, complicated and most accurate timer, since it consists of complex circuit - The patient is measured, and the based upon the time required to charge a back-up mAs is set at 2x the capacitor. normal mAs. - Radiation is measured at the - Electronic timer center of the film or off to the Most units have this type of timer. sides of the film. - The center is read for most - Electronic timer radiography and especially for the spine A type of modern machine that is - The sides are read for PA chest, designed to accurately control the tube abdomen and rib radiography. current and exposure time. The rotor of control console can spin up - mAs timer to? It is special type of monitor the - 3400 RPM product of mA and terminates the exposure when the desired mAs has been What color of light will let you know attained. that the machine is ready to make the exposure? - mAs timer - A green light Designed to provide the shortest exposure and the highest safe tube It is often depressed and the exposure current for the given filaments. is initiated. - mAs timer - Exposure button What does APT stand for? What will happen to the exposure if your finger slips off the button of the - Anatomically Programs Timers exposure button? It measures the quantity of radiation - The exposure is terminated reaching the receptor and terminates the exposure when sufficient radiation The exposure control buttons are needed to produce correct density on the referred to as? film. - Dead man Switch - Phototimer Fact: It is commonly referred to as Automatic Exposure Control or AEC. 1. During the exposure you will hear an audible tone so you will know - Phototimer that the exposure is in progress. What are the two types of phototimers? This voltage section converts low voltage from incoming power to kilo- - Photomultiplier tube that reads a voltage of the correct wave form. It is fluorescent screen and behind the usually enclosed in a large metal filam. container in the x-ray. - Ion chamber between the grid and film - High voltage section It is used in most modern x-ray units. The high voltage section consists of three primary sections, what are these? - Ion chamber - High voltage step up transformer It can be used to optimize the image. - Filament transformer - Multiplier chambers - Rectifiers (Diodes) All components immersed in oil. With AEC console, an operator can do the ff. What kind of transformer is the high voltage transformer? - Do not measure the patient and set an arbitrary back up mAs or time. - Step up transformer The ratio of windings is referred to as? This power has technical factor cut into half due to more efficient power. And - Turns ratio this is too expensive got office use. What is the only difference between the - Thee-phase power primary and secondary waveforms? Facts: - Amplitude 1. Changing the frequency from 60 Hz What is the turn ratio for most x-ray to a higher frequency of 500 to high voltage transformer? 1000, the ripple is reduced o less - Between 500 and 1000 than 1%. 2. Single phase machine operating on The incoming volts converted to output 220 volts and even 110 volts are becomes? more efficient that machine operating on three-phase power. - Kilovolts If 220-volt power is not available, the Transformers operate with what king of operator my choose to use what machine? current in voltage rectification? - Stored energy machine - Alternating current What do we call the disadvantage to the To convert AC to DC, what do we use? design which is a drop in power at the - Rectifiers end of the exposure of about 1kV/mAs? What is it called when the x-ray tube - Falling load generator alone will work as the diode? A type of generator that is cheap but - Self-rectification not efficient. What is it called when one or two diodes - Single-phase half or self- are placed in the circuit that stops the rectified negative flow of electrons? An expensive type of generator to - Half wave rectification install but cheaper to maintain. And it is too costly for most offices. 6 pulses How many pulses per second is observed less costly than 12 pulses. in half wave rectification? - Three phase - 60 pulses per second A type of generator that is very Full wave rectified x-ray machines efficient and works with single or three contain at least how many diodes? phase power. - At least 4 diodes - High frequency This rectification changes the polarity This generator works on conventional of the negative half of the wave. 110-volt power, but batteries must be - Full-wave rectification replaced. How many pulses is observed in full-wave - Stored energy rectification? It is a circuit that make up the basic - 120 pulses per second x-ray machine. Fact: - Basic x-ray circuits 1. If three phases of power are Ir is attached to the x-ray tube below combines with the phase off by one glass window where the useful beam is step, the normal reduction of emitted. voltage back to zero is removed, - The collimator commonly called as the ripple. It is our greatest tool in keeping It is found in many radiology patient exposure as low as possible. departments, has very different image receptor. - Collimation - Digital radiography It allows dynamic imaging of the body. It is used in computed radiography (CR), - Fluoroscopy equipment and is the most common digital image Who invented the fluoroscopy in 1896? receptor. - Thomas Edison - Photostimulable Fact: This involves the flat panel detector that vontains an electronic array. 1. Fluoroscopy tube operate at less than 5 mA. 2 to 4 is normal. - Direct digital radiography (DR) After the world war II, who invented the It is less commonly used in radiographic photomultiplier tube? imging, also use an electronic process to convert light to a digital signal. - Bell laboratories - Charge-coupled devices (CCD) How many potential volts is maintained between the photocathode and the anode? These are used in medical imaging departments, depending on the specific - 25,000 application. One of the uses of fluoroscopy ia the - Screen types of radiographic film Dynamic spinal imaging of range of motion and with contrast called? Film manufacturers produce film in a variety of sizes, ranging from what? - Myelograms - 20x25 cm (8x10 inches) to 35x43 It studies the joints with or without (14x17 inches) contrast media, and the digestive system, and the arteries and blood flow It is the smallest size of a film. called angiography. - 20x25 cm or 8x10 inches - Fluoroscopy It is the largest size of a film. - 35x43 cm or 14x17 inches CHAPTER 12 This type of film has two sensitive emulsion layers, one on each side of base. And it is used for most general It is the most common film screen image applications. receptor used in radiography today. - Duplitized umlsion - Double-emulsion radiographic film These are also used for intraoral dental These screens absorb the transmitted x- film. rays and produce light, which exposes the film. - Duplitized emulsion - Intensifying screens These thin layer of polyester (polyethylene terephthalate), Which It is the rigid, light-tight container transmit light and provides a support that holds the screens and film in close for the layers. contact. - Film base - Cassette It is the foundation of the radiographic film. And a flexible fracture-resistant to allow easy handling. - Film base  What are the purposes? Whta is the primary purpise of film - To enhance contrast base? - To reduce glare - To provide a rigid structure onto What do we call the oroperty of a which the emulsion cn be coated radiographic film when it maintains its size and shape dueing the use and Approximately, how thuck is the film processing so that it does not base? contribute to the image distortion? - 150 to 300 micrometer - Dimensional stability And what it is made of (film base? It is the thun, strong adhesive layer - Semi-rigid lucent polyester that binds the base to emulsion. It plays a bital role in ensuring that It is the original film base used during these do nit separate while processing. WW1 - Substratum or subbing layer - Glass plate The substratum layer is usually a It is the substitute material for glass mixture of what? plate. - Solvent and gelatin - Cellulose nitrate It is a suspension of light/radiation- Why is it dangerous to use the cellulose sensitive silver halides suspended nitrate? within a gelatin binder. - It is flammable - Emulsion layer What causes the several hospital fires It is a very thun coating if hardened during the 1929s and and early 1930s? gelatin that protects the sensitive wmulsion layer against mechanical damage - Improper handling of x-ray film that can arise from handling and files (cellulose nitrate films) transport within manual. It replaced cellulose nitrate in mid- - Superciat/anti-abrasive layer 1920s film with safety base. How high should the temperature when - Cellulose triacetate storing the film? It was introduced as film base in early - No greater than 68 to 70 degrees 1960s. It has taken place of cellulose fahrenheit. truacetate as the film base of choice. How about the humidity? - Polyester (polyethylene teraphthalate) - 40% to 60% It is more resistant to warping from age What are the four factors to keep it and is stronger than cellulose away with, in order to prevent increased triacetate, but thinner than triacetate density and fog? bases. - Radiation - Polyester - Fumes - Outdating How thinnis the polyester film? - Light - Approximately 175 micron Should you store it (radiographic film) What color of dy is added to the in a flat surface or boxes? polyester film base? - No - Blue dye How should you handle the film? - Pressure marks - Static What causes the film to have crinkle or It is referred as the emission of light half-moon marks? by a substance when excited by any form of energy. - Bending film - Rough handling - Luminescence What are the different types of film? What are the two steps involved in luminescence? - Nonscreen film - Copy film - Initial energy causes the elctrons - Film badge of the atoms of the abosorbing - Dental film material to become excited and - Bite-wing film jump from their inner orbits to - Spot film the outer orbits. - The electrons fall back to their A film for getting very fine detail, original state, a photon of light used without a cassette and requiring is emitted. long exposure. Ehat is the interval between the two - Nonscreen film steps? A film with a special reversal emulsion - Maybe shor (1/100000 of a sec)or so that a contact print can be made with long (many hours) white light. If the interval is short, the process is - Copy film called? A film worn as a badge and used for - Fluorescent detection and approximate measurement of radiographic exposure of personnel. If the interval is long, the process is called? - Film badge - Phosphorescence A nonscreen film used in dental radiography. The emission of light which cease within 10^-8 seconds of the removal of the - Dental film luminescnet energy source. (No after An x-ray film iwith protruding tab to be glow) held between the upper and lower teeth. - Fluorescence - Bite-wing film The emission of light which continues on A film of a small anatomic area obtained or is delayed after the removal of tge (1) by rapid exposure dueing fluoroscopy luminescencent energy source is to provide q permanent record of a removed.(fade slowly in the dark closet) teansiently. (2) by limiting of - Phosphoresence radiation passing through the area to improve definition and detail of the It is the layer of the intensifying image produced. screen closest to the x-ray film. It is 15 to 25 micrometer thick and is applied - Spot film to the face of the screen to make the What is the efficiency of an x-ray film screen resistant to abrasion. to absorb x-rau photons? - Supercoat or protective layer - 1% It is the active layer of the What is the purpose of intensifying intensifying screen. The phosphor emits screen? the light during stimulation by x-rays. - To amplify the film blackening - Phosphor layer 100-200 micron eefectnon the film exposure by the comvertion of x-ray photons to light photons What is the only one purpise of What element is the atomic number 39, phosphor? which is sometimes included in rare earth elements. - To convert the nergy of the x-ray beam intro visible light - Yttrium Facts about phosphor: What element is the atomic number 21, which is sometimes included in rare 1. High x-ray absorption and light earth elements. efficiency 2. Emission spectral matched to film - Scandium sensitivity What elements with atomic numbers 58 and 3. Fast light emission 71 are commonly known as the lanthanide 4. Absence of afterglow series? 5. Uniform light output - Cerium Whatbre the types of phosphor? - Lutetium - Silver zinc sulphide Facts: - Barium kead sulphate - Rare earth phosphors 1. Gadolinium (Gd), Yttrium (Y), and Lanthanum (La) and the most used The early phojors ,ain blue emitters compounds are their oxy-sulphides around 300-420 nm calcium tungsten, was (O2S) with activators Terbium and discovered in? Europium with Terbium the most - 1897 common. The rare earth elements include the The substratum layer 10-20 micron has elements with atomic numbers of? two types, what are these? - 57-71 - Reflective layer - Absorptve layer Enumerate these elements in order: It is placed between the base and the 57. Lanthanum phosphor layer to reflect as much of the 58. Cerium light produced towards the film. 59. Praseodymium - Reflective layer 60. Neodymium Used to maximize the halation effect. It controls the screens light output cam be 61. Promethium used to match screens into a graduated series for specialists applications. 62. Samarium - Absoprtive layer 63. Europium It acts as a support for the other layer 64. Gadolinium and common materials include card, 65. Terbium polyester and plastic. 66. Dyspeosium - base layer 200-400 micron 67. Holmium It is a separate measured quantity to film speed or film screen combination 68. Erbium speed. 69. Thulium - Screen speed 70. Ytterbium What is comsidered as the base speed 71. Lutetium number? - 100 What is the formula in intensifying It is often linked to a daylight factor (IF)? handling system for the loafing and unloading of cassette. - IF = exposure without screens (over/)exposure with screens - Automatic processing It allows the exposure calculations and Fact: modifications when the rafiographed is 1. The radiograph is said to contain moving from one film screen to another. a latent (hidden) image because - Relative speed numbers (RS) the change in the grains is virtually undetectable, but the What is the formulas for relative speed? exposed grains are now more - mAs1/mAs2=RS2/RS1 sensitive to reactionmwith the - Old mAs/New mAs = New relative developer. speed/Old relative speed What are the five steps in processing a Fact: film? 1. Generally, slower systems are used 1. Development for extremity radiography, fater 2. Stopping the development systems are used formspine, 3. Fixing abdomen, trauma,and pediatric 4. Washing radiography, 5. Drying It is one of the principal influence on The film is dried for viewing. image contrasts. - Drying - Screen influence The film is washed with water to rmove The screen contrast is affected by? all the processing chemicals. - X-ray photon kV - Washing - Phosphor type Unexposed silver halide crystals are - Speed difference between front and removed by the fixing bath. back screen - Fixing It is a film screen combination exposed to a uniform field of exposure produces The stop bath simply stops the an image with a mottled appearance which development process by diluting and is not due tot he grain structure of the washing the debeloper away. film. - Stopping the development - Quantum mottle The developing agent gives up electrons Intensifying screens are in general ro convert the silver halide graisn to mounted in pairs into a cassette and metalic silver. normally there is no distinction between - Development front and back. It is a strict science governed by rigid - Mounting rules of chemical concentration, Fact: temperature, time, and physical movement. 1. Excemption to mounting are the mammography and high details usage - Processing film applications where there may only It is a chemical process that magnifies be a single screen. the invisible latent image into visible It is the final stage in the production halide image. The solution used for this of hardcopy x-ray image. is called developer. - Processing - Development It converts the exposed silver ion into Fact: black metallic silver, by reduction 1. Undesirable changes to the pH process (addition of electron). levels of developer solution may - Developer occur as a result of both aerial oxidation and the acid by-products What are the constituents of the of the development process. developer? What are the factors imfluemcing the - Developing agent development rate? - Accelerator - Restrainer - pH od the solution - Water - Solution temperature - The use of potassium sulphite as - Nature of the developing agent preservatives - Development time - Bactericides and fungucides It continues the process of film - Hardener hardening and terminates the further It supplies electrons for the process of development. reduction. It is normally a combination - Fixation of two specific developing—producing a PQ developer. What are the constituents of fixer? - Developing agent - Ammonium thiosulfate - Acetic acid Provides alkaline environment, pH ranges - Aluminum salts 9.8-11.4 to allow the developer to - Water function effectively. - Preservative - Accelerator - Boric - Buffers Usually benzotriazole, acts to aid the selectivity of the developing agent, The fixing agent is rapid acting and helping to orevent conversion of combines with underdeveloped silver unexposed silver halides. halides to form a soluble silver compound that then migrates through a - Restrainer process of osmosis. It is used as a solvent as it us clean - Amonium thiosulfate and free from chemical deposits and is the medium in which the other developer Ensures the development is terminated constituents are mixed. and provides an appropriate environment. - Water - Acetic acid It acts to reduce the rate of aerial Are commonly used as hardeners to reduce ocidation of the developing agent and to the drying time and enhance the facilitate the generation. hardening effects. - The use of potassium sulphite as - Aluminum Salt preservative Serves as solvent It acts to restrain growth of organism - water within the solution. Reduces the rate at which the fixing - Bactericides and fungicides agent decomposes. It reduces the chances of damage to the - Preservatives emulsion layer during transportation or the film becoming stuck in the Is used as an anti-sludging agent to processor. reduce the rate at which the aluminum dalts may precipitate. - Hardener - Boric acid Acts to control the pH of the solution 3. The wet side, should be used to by neutralizing the effects of the process the film. alkaline developer solution. - buffers The ibjective of orocessing is two-fold, What are the factors affecting fixation what are these? rate? - To produce a radiograph adequate - Presence of hardeners (slows for viewing, and process) - To orepare the radiograph for - High concentration of the silver archival storage. complexes in solution in pH (pH Radiographs are often stored for how should be constant) many years as the record of the - Nature and concentration of fixing inspection? agent - 20 years or more This stage us designed to remove both residual fixer chemicals and silver Is it essential piece of equipment in salts from the film emulsion. every x-ray department. This will reduce film processing time when compared to - Washing manual development by a favtor four. Is washing a 100% effective? - Automatic processor - No What should be carried out to evaluate Fact: if the performance of films in the sutomatic processor is being maximized. 1. Washing is most effective when the film is exposed to a continuous - Sensitometric checks fliw ir spray of uncontaminated What are the three measurements used in water. sensitometric checks? It is used to evaporate excess moisture - Fog level from the film. - Speed - Air - Average gradient It accelerates the process, as do air Fact: circulation. 1. The basic components within an - Air of low humidity (dry air) automatic processor are very similar despit the differences Fact: that occur between manufacturers 1. Approximately 15% of the dry film products in relation to design and is actually moisture film capacity. Where don,anual processing begins? It is essentially a light-tught box containing a series of processing tanks - In the darkroom and a roller transport mechanism. It is often a metal bin that is used to - Processor store and protect the film. What does the corssover assemblies, - Tught compartment located between adjacent processing tanks utilize to remove much surface Facts: liquid? 1. Film should be located in a light, - Squeegee rollers tught compartment 2. An area next to the film bin that To maintain image quality temoerature is dry and free of dust and dirt must be maintained within? should be used to load and unload the film. - 0.5 degree celsius This facilitates the emptying of the It is the most common transport system tank for routine cleaning and and us associated with high capacity maintenance. It is usually a length of processor. plastic tubung which is screwed into a - Deep or vertical rack system drain hole in the base of the tank. Rollers fit into distinct categories, - Drainage system what are these? This pumps fresh developers solution - Hard (made from PVC) into the tank, maintaining the activity - Soft (made from neoprene) and quantity of developer within the tank. This is a type material roller taht guide the film. - Replenishment system - Hard roller This system requires inlet and outlet pipes, an electric pump and possibly a This is a type material roller that filter to ensure agitation and include both the squeegee rollers and recirculation of the solution. those needed for where extra grip is neessary to change direction. - Recirculaty system - Soft roller This section contains drainage, recirculatory and replenisher systems This roller play an important in that are similar in fucntion to those reducing carry-over rate of chemicals. within the developer section. - Squeegee roller - Fixer section This system activates all the main This section aims to remove both processor functions, and, in instances residual fixer complexes and silver when manual loading of the processor complexes, thus improving archival occurs, gives an audible signal taht is permanence of the film. safe. - Wash section - film feed system What are the different types of wash It occurs when a film activates a switch section available? in the entry roller. - Spary rinse - Entry roller detection - Tank of running water with a flow rate of 7 L It is placed just inside the processor behind the entry roller assembly. There is danger to the film emulsion if the air used for drying is too hot. - Infrared detectors - Drying section This calculate the film size and the required amount of replishment. What are the diffeent types of drying systems available? - Replishment system - Infrared drying It can be used the same way as film- - Hot air drying screen cassettes: in the Bucky, on the tabletop, or on mobile exams. And it is This is where the heat from electrically a cassette-based system. heated elements is radiated onto the film whilst. - Computed Radiography Image Receptor (CRIR) - Infrared drying Give the comparison of conventional This ensures heated, filtered air is screen versus imaging phosphor plate. directed tubes onto the film from a series of cylindrical tubes. - Conventional scree: a. Intensifying screen layers - Hot air drying b. Protective layers c. Rare earth phosphor layer  d. Reflective layer - A display devices with view e. Polyester base support layer operated controls This image receptor differs - Imaging phosphor plate significantly among the three types of a. Imaging plate layers image receptor, because it is the result b. Protective layers of deposits of silver ions at the c. Barium fluorohalide phosphor layer sensitivity specks in the emulsion. d. Reflective layer e. Conductive layer - Latent image receptor f. Polyester base support layer g. Light shielding layer This image receptor is formed by h. Backing layer electrons traooed in the barium fluorohalide crystals (in the phosphor Facts: layers). 1. If the CR imaging plates are nor - CR latent image used within 48 hours, they should be put through an erasure cycle before use. CHAPTER 13 2. CR imgaging plates should be processed within 1 hour of exposure, otherwise fading of the latent image wi begin to impact It is an evacuated glass bulb with image quality. positive (anode) and negative (cathode) 3. When using the CR, it is electrodes. appropriate to asjust the mAs as - X-ray tube if using a 200-speed film-screen system. Since many regular film- It is an electrode toward which screen combinations are 400-speed negatively charged electrons migrate. this requires doubling the mAs. - Anode It uses a flat panel direct capture Is a filament that gives iff electrons detector array that absorbs radiation when heated (the source of electrons). and converts the energy into electrical signals. And it is cassetteless system, - Cathode since it is in a permanent location. Fact: - Direct digital radiography (DR) 1. The primary by-product of energy Is DR easy to use for monile exams? conversion is 99% heat and less than 1% is x-ray. - No It enhances the images if the body, but Fact: it does not provide cross-sectional 1. Typically, the DR is 14x17 or views. 17x17 inches in size - Digital imaging What does TFT stand for? A sheet of plastic that is embedded with - Thin film transistor crystals called phosphors. A digital radiography is performed by - Intensifying screen system consisting of the different Fact: functions, what are those? 1. In the interest of patient safety, - A Digital IR it is imperative that dosages be - A Digital image processing unit kept as low as possible. - An image management system 2. Approximately 95% of the image on - Image and data storage devices the film is made by light from the - Interface to a patient information intensifying screens, only 5% of system the image directly by the x-ray. - A communications network A sheet of polyester plastic coated with This can be performed if the patient a thin layer of gelatin and silver cannot be moved from conventional compounds. electrical circuits. - X-ray film - Portable radiography and fluoroscopy Is the permanent record of the examintion of the x-ray film can be This operates from conventional considered a legal document? electrical circuit or battery power. - Yes - Mobile radiography units It provides a live-action view of the It is used in such areas as the OR, PAR, internal part of the body. ICU, ICU, CCU, etc. - Fluoroscopy - Portable radiography Where is the x-ray tube located? It is used primarily in the operating room, where the surgeon must see the - Inside the x-ray table images immediately. It uses animage intesifier that improves - Mobile fuoroscopy and enhances the image and transmits it to the televison monitor. It must be used with greater care to prevent those involved— both workers and - Fluoroscopy patients from being unnecessary It provides a cross-sectional views of radiated. the body. - Portable fluoroscopy - Computed tomography A technique used to obtain radiographs This is able to obtain several dozen of a section or slice of a body part, as slices of information with one exposure. in the use of computed tomography. - CT scanner - Tomogrpahy It allows cross-sectional views of the It uses high frequency sound waves, body to be made without the use of which is a form of non-ionizing ionizing radiation. radiation, to obtain sectional images of the body. - Magnetic resonance imaging - Sonography It is ismilar to nuclear medicine in that it uses a radiopharceutical It is oriinally used by military to injected into the circulatory system to detect enemy submarines image the area of interest. - Sonography - Positron emission tomography Can the evaluation of moving organs can It is used to evaluate the physilogy or also be made using sonography? function of an organ or system un the - Yes body. What technique is used to evaluate the - Positron emission tomography blood flow through the arteries? It is treated by the body muck like its - Doppler technique own natirally occuring components, the information acquired is a highly It brings digital imaging together with accurate representation of the function howpital and radiology information of the area in question. systems, it allows for the total management of a patient’s case. - Radiopharmaceutical - Picture archiving and communication system (PACS) Where do data are being stored? - Optical disks It is a standard protocol used for blending PACS. - Digital imaging and communications in medicine (DICOM) It is a type of nuclear imaging test that shows how blood flows to tissues qnd organs. It is able to privide true 3D information. - Single photon emission computed tomography (SPECT) What kimd of rays is used in SPECT? - Gamma rays It is the gamma-emitting radioisotopes. - Radionuclide It is a simple soluble dissolved ion, such as radioisotopes of gallium (III) which happens to also have chemical properties that allows it to be concentrated. - Radioisotopes What are the applications of SPECT? - Myocardial perfusion imaging - Functional brain imaging