The steeper the straight-line portion of a characteristic curve for a particular film, the

The Blurred Mask Subtraction is often used, especially in digital radiography, to enhance the visibility of detail in certain clinical procedures.

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What is straight
What is H and D curve in radiography?
Which area on the characteristic curve represents high exposure levels?
Which region of the characteristic curve represents the inherent density in the film?

Important point....This process does not un-blur an image and recover detail that was completely lost because of blurring from the focal spot, motion, and the receptor. What it does do is increase the visibility (contrast) of some objects, especially where the visibility of the objects is somewhat limited by large area contrast as in chest imaging.

The process consist of two distinct steps. First, a blurred copy of the original image is produced. A common form of digital processing that can be used to produce a blurred image is just by replacing each pixel value with the average of the pixel values in it's neighborhood. This produces a "blurred mask" image.

The blurring removes all detail from the image (that is what blurring does!). We now have two images. The original image contains the general large-area contrast background plus some detail. The blurred mask image contains only the large-area contrast background

The final step is where the computer subtracts the blurred mask image (actually some fraction of it) from the original image.

This process reduces the large-area contrast background in relation to the contrast of the detail. The result is that the contrast and visibility of the detail (small objects and structures) in enhanced.

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Question	Answer
The photon tissue interaction in diagnostic radiography that results in the total absorption of an x-ray photon and the production of contrast in the radiographic image is: A) Compton's B) coherent C) photoelectric D) pair production	C
The traditional unit of in-air exposure is the: A) Coulombs/kilogram B) Rem C) Becquerel D) Roentgen	D
The traditional unit of dose equivalency is the: A) Rem B) Gray C) Quality factor D) LET	A
The amount of radiation deposited per unit length of tissue traversed by incoming photons is called: A) tissue exposure B) linear deposition of energy C) linear energy transfer D) absorbed dose equivalent limit	C
Compton's interaction: 1. produces contrast in the radiographic image 2. results in scattering of the incident photon 3. may produce fog on the radiograph 4. knocks outer orbital shell electron out of orbit	2, 3 and 4 only
Cataractogenesis, life span shortening, embryologic effects, and carcinogenesis are examples of A) short term somatic effects B) genetic effects C) acute radiation syndrome D) long term somatic effects	D
What agency publishes radiation protection recommendations? A) ICRP B) NCRP C) NRC D) ASRT	B
Which of the following states that the radiosensitivity of cells is directly proportional to their reproductive activity and inversely proportional to their degree of differentiation?	A) Inverse square law B) Law of Bergonie and Tribondeau C) Reciprocity law D) Ohm's law B
When radiation strikes DNA which of the following will occur? A) Direct effect B) Law of Bergonie and Tribondeau C) target theory D) indirect effect	A
The effective absorbed dose equivalent limit for radiographers is: A) 3 rem per quarter B) 500 mrem per year C) 5000 mrem per year D) 100 mrem per month	C
The annual effective absorbed dose equivalent for the general public, assuming infrequent exposure, is: A) 0.5 mrem B) 500 rem C) 0.5 rem D) 50 mrem	C
Film badges are generally accurate down to the level of: A) 10 rem B) 5 rem C) 0.1 mrem D) 10 mrem	D
Under what conditions may the radiographers be exposed to the primary beam?	A) When performing moblie rdiograpghy, as long as exposure is low B) not under any conditions C) When preforming crosstable projections, if needed to hold the casette in place D) When assisting with fluoroscopy B
Gonadal shielding should be used: A) On every exam performed B) Whenever it will not obstruct the area of clinical interest C) Only when children and women of childbearing age are imaged D) Only during pergnancy	B
Atomic number refers to: A) The number of protons plus the number of neutrons B) The number of elctrons C) The number of electron shells D) The number of protons	D
The force that holds electrons in orbit around a nucleus is called: A) Gravity B) Atomic Force C) Electron binding energy D) Ironization energy	C
The distance between the peaks of a sine wave of x-rays is called: A) Wavelength B) Altitude C) Amplitude D) Frequency	A
The transformer that makes the use of variable kVp possible is the: A) Step-up transformer B) Step-down transformer C) Induction transformer D) Autotransformer	D
What safety feature is required when using automatic exposure control? A) The minimum response time B) The falling load generator C) The backup timer D) The ionization chamber	C
Devices in the x-ray circuit that increase or decrease voltage are called: A) Rectifiers B) Generators C) Timers D) Transformers	D
Because the x-rays requires direct current to operate properly, what device is required in the x-rays circuit? A) Autotransformer B) Step-up transformer C) Rectifier D) Falling load generator	C
Thermionic emission occurs at the: A) Anode B) Control panel C) Rectifier D) Cathode	D
An interaction that primarily produces heat at the anode but that also produces the majority of x-rays is called: A) Characteristic B) Bremsstranhlung C) Compton's D) Photoelectric	B
When a quality control test for exposure linerity is performed, adjacent mA stations must be within this amount of one another: A) 2% of SID B) 4% C) 10% D) 5%	C
When a quality control test for collimator accuracy is performed, the result must be within this amount: A) 2% of SID B) 4% C) 10% D) 5%	A
The accuracy of collimation of a 72-inch SID must be: A) +/- 1.44 inches B) +/- 7.2 inches C) +/- 3.6 inches D) +/- 0.02 inch	A
The feature of the image intensifier that ensures the radiation striking the input phosphor is constant is the: A) Photocathode B) Electron focusing lens C) Atomtic brightness control D) Vidicon tude	C
The electronic device that may be used for many quality control tests on x-ray equipment is the: A) Automatic exposure control B) Digital dosimeter C) Penetrometer D) Densitometer	B
The image in the emulsion of a film, before processing, is called: A) Manifest-image B) Image-in-waiting C) Perprocessed image D) Latent image	D
Given an original technique of 15 mAs and 75 kVp, which of the following will produce a radiograph with double the density? A) 40 mAs, 75 Kvp B) 30 mAs, 75 kVp C) 40 mAs, 80 kVp D) 15 mAs, 92 kVp	B
Unwanted markings on a radiogrph are called: A) Processing irregularities B) Processing artifacts C) Artifacts D) Plus-density markings	C
The entire processor should be cleaned every: A) day B) week C) month D) 6 months	C
Speed and contrast values measured during sensitometric testing should not vary more than how much from the baseline? A) 5% B) 1% C) 15% D) 10%	D
A malfuction in which the developer temperature runs too high will cause: A) Dark films B) Light films C) Milky films D) Greasy films	A
A malfunction in which there is a white light leak into the processing room will cause: A) Fogged films B) Light films C) Milky films D) Tacky films	A
Which of the following systems moves the film and agitates the chemistry? A) Transport B) Replenishment C) Recirculation D) Dryer	A
which of the following systems removes reaction particles from the developer solution by sending it through a filter? A) Transoprt B) Replenishment C) Recirculation D) Dryer	C
Which of the following grid errors will result in an image that shows normal density in the middle but decreased density in the sides, assuming the correct side of the grids faces the x-ray tube?	A) Upside down B) off-level C) Grid-focus decentering D) Lateral decentering C
Grid ratio is described by which of the following? A) H & D B) H/D C) mAs=mAs D) 15% rule	B
The aspect of a film-screen system that may be examined by conducting a wire mesh test is the: A) Phosphor layer B) Reflective layer C) Protective layer D) Film-screen Contact	D
The portion of an intensifying screen that is made of polyester is the: A) Active layer B) Reflective layer C) Protective layer D) Base	D
A slower film-screen system will exhibit: A) Lower contrast B) Narrower latitude C) Poorer recorded detail D) Increased density	A
The section of an H & D curve that represents D-max is the: A) Shoulder B) Toe C) Body D) x-axis	A
As kVp is increased: A) Density decreases B) Contrast increases C) Recorded detail increases D) Contrast decreases	D
Which of the following sets of exposure factors will produce the radiograph with the best recorded detail?	A) 60 mAs, 80 kVp, 40-inch SID, 4-inch OID B) 30 mAs, 92 kVp, 40-inch SID, 4-inch OID C) 120 mAs, 92 kVp, 40-inch SID, 4-inch OID D) All would produce equal recorded detail D
Which of the following sets of exposure factors will produce the radiograph with the most magnification?	A) 60 mAs, 80 kVp, 40-inch SID, 4-OID B) 30 mAs, 92 kVp, 40-inch SID, 2-inch OID C) 120 mAs, 92 kVp, 20-inch SID, 4-inch OID D) 15 mAs, 100 kVp, 20-inch SID, 2-inch OID C
Beam restriction has the following effect on contrast: A) Decreases contrast B) Increases contrast C) Longer scale of contrast D) No effect on contrast	B
A "typical" skull would be described as: A) Synarthrose B) Amphiarthroses C) Diarthroses D) Mesocephalic	D
Fibrous joints are called: A) Synarthroses B) Amphiarthrosed C) Diarthroses D) Mesocphalic	A
The proximal radioulnar articulation has what type of movement? A) Hinge B) Pivot C) Saddle D) Gliding	B
Which of the following bones has an alveolar process? A) Sphenoid bones B) Ethmoid bone C) Zygoma D) Maxilla	D
Which of the following bones has a sagittal suture? A) Frontal bone B) Temporal bones C) Occipital bone D) Parietal bone	D
Which of the following bones has a trochlear sulcus? A) humerus B) ulna C) radius D) elbow	A
The blunt cartilaginous tip of the sternum is the: A) Manubrium B) Floating C) Xiphiod D) Jugular notch	C
This bone is located in the wrist, between the trapezoid and the hamate: A) Scaphoid B) Hamate C) Pisiform D) Capitate	D
This bone is located in the wrist, between the lunate and the pisiform: A) Scaphoid B) Hamate C) Pisiform D) Triquetrum	D
This bone lies along the lateral border of the navicular bone: A) Scaphoid B) Calcaneus C) Talus D) Cuboid	D
This structure has superior, middle, and inferior lobes: A) Trachea B) Left lung C) Right lung D) Hilus	C
The narrow distal end of the stomach that connects with the small intestine is called the: A) Rugae B) Pylorus C) Fundus D) Greater curvature	B
The lateral surface of the stomach is called the: A) Lesser curvature B) Pylorus C) Fundus D) Greater curvature	D
The portion of the small bowel that connects with the cecum is called the: A) Duodenum B) Jejunum C) Ileum D) Ascending	C
The outer part of the kidney is called the: A) Cortex B) Medulla C) Nephron D) Glomeruli	A
For radiography of a finger, the central ray enters: C) Parallel to the proximal interphalangeal joint D) Perpendicular to the proximal interphalangeal joint	D
For a lateral projection of the wrist, the elbow must be flexed: A) 45 degrees B) 90 degrees C) Only slightly D) Approximately 25 degrees	B
For an AP projection of the toes, the central ray enters at the: A) Third metatarsophalangeal joint B) Second metacarpophalangeal joint C) First metatarsophalangeal joint D) Second metatarsophalangeal joint	A
For an axial projection of the calcaneus, the central ray is angled how many degrees to the long axis of the foot: A) 25 B) 50 C) 10 D) 40	D
For an AP projection of the knee, with measurement taken at the ASIS of 26cm, the central ray is angled: A) 5 to 7 degrees cephalad B) 5 to 7 degrees caudad C) 10 degrees cephalad D) 10 degrees caudad	A
For a lateral projection of the cervical spine, the central ray is directed: A) Perpendicular to C4 B) Parallel to C4 C) 15 to 20 degrees caudad to C4 D) 15 to 20 degrees cephalad to C4	A
For an AP projection of the lumbar spine, the central ray is directed:	A) Parallel to the midline, entering at the level of the iliac crests B) Perpendicular to L2 C) Perpendicular to the midline, entering at the level of the iliac crests D) Perpendicular to L3 C
For the PA projection of the chest, the central ray is directed: A) Perpendicular to T10 B) Parallel to the thoracic spine C) Perpendicular to T7 D) Perpendicular to the posterior ribs	C
For the AP axial (Towne) projection for the skull, the central ray is directed: A) 30 degrees to the IOML B) 37 degrees to the OML C) 25 degrees to the IOML D) 30 degrees to the OML	D
For the parietoacanthial projection (Waters) for the sinuses, the OML forms an angle of how many degrees with the IR? A) 53 B) 37 C) 25 D) 45	B
The pelvocalyceal system will reach greatest visualization approximately how many minutes after injection of contrast? A) 1 to 2 B) 2 to 5 C) 2 to 8 D) 15 to 20	D
Violations of civil law are known as: A) Assault B) Battery C) False imprisonment D) Torts	D
Verbally spreading false information that defames another's character could lead to a charge of: A) Respondeat superior B) Res ipsa loquitur C) Gross negligence D) Slander	D
Tachycardia indicates a pulse of: A) more than 100 beats perminute B) fewer than 60 beats per minute C) greater than 90 beats per minute D) less than 50 beats per minute	A
When oxygen is administered to the patient thru nasal cannula, the usual flow rate is: A) 1 to 5 L per second B) 5 L per hour C) 3 to 5 L per minute D) 10 to 15 L per minute	C
This item is used to restore the heart to normal rhythm: A) Crash cart B) Suction unit C) Defibrillator D) Sphygmomanometer	C
The item that is used to feed the patient or to suction gastric contents is the: A) Ventilator B) nasogastric tube C) Chest tube D) Vanous catheter	B
A patient unable to extend his/her arm is seated at the end of the x-ray table, elbow flexed 90 degrees. The CR is directed 45 degrees medially. Which of the following structures will be demonstrated best? 1. Radial head 2. Capitulum 3. Coronoid proces	1 and 2
In the PA position and the OML perpendicular to the table, a 15-20 degree caudal angulation would place the petrous reidges in the lower third of the orbit. To achieve the same result in a baby or small child, it is necessary to modify the angulation to	A) 10-15 degrees caudal B) 25-30 degrees caudal C) 15-20 degrees cepahlic D) 3-5 degrees caudal A
In the adult the OML and IOML are 7 degrees apart. In infants and small children the OML and IOML are 15 degrees apart. In adults the head makes up about 1/7 of the length of the body; in children the head is about 1/4 the length of the body	x
Baruim sulfate is administered in GI studies as: A) solution B) suspension C) crystals D) organic salt	B
A reaction that may occur in the vein in which the injection occured is: A) Systemic irritation B) Cardiovascular C) Anaphylactic D) Phlebitis	D
This type of infection transmission occurs as a result of coughing or sneezing: A) Contact transmission B) Airborne transmission C) Droplet transmission D) Common vehicle transmission	C
The complete removal of an organism from equipment and the enviroment in which patient care is conducted is called: A) Medical asepsis B) Surgical asepsis C) Standard precautions D) Gas sterilization	B
Soaking objects in germicidal solution causes: A) Medical asepsis B) Surgical asepsis C) Standard precautions D) Chemical sterilization	D
The abbreviation that means "nothing by mouth" is: A) hx B) bx C) CVA D) NPO	D
The word part that means "Kidney" is: A) viscer B) megal C) trans D) nephr	D
Examples of COPD include 1. bronchitis 2. pulmonary emphysema 3. asthma	1,2,3
Forms of intentional misconduct include: 1. slander 2. invasion of privacy 3. negligence	1 and 2
Which of the following conditions describes a patient who is unable to breathe easily while in a recumbent position? A) dyspnea B) apnea C) orthopnea D) oligopnea	C
Which ethical principle is related to the theory that patients have the right to decide what will or will not be done to them? A) Autonomy B) Beneficence C) Fidelity D) Veracity	A
Which of the following exams require(s) restriction of the patient's diet? 1. GI series 2. Abdominal survey 3. Pyelogram	1 and 3
The diameter of a needle is termed the: A) bevel B) gauge C) hub D) length	B
To best demonstrate esophageal varices, the patient must be examined in the: A) recumbent position B) erect position C) anatomic position D) Fowler's position	A
Which of the following projections of the abdomen may be used to demonstrate air or fluid levels? 1. Dorsal decubitus 2 Lateral decubitus 3. AP Trendelenburg	1 and 2
Which of the following positions will demonstrate the right axillary ribs? 1. RAO 2. LAO 3. RPO	2 and 3
During myelography, contrast medium is introduced into the A) subdural space B) subarachnoid space C) epidural space D) epidermal space	B
Again, using the above cooling chart, if the tube contains 150,000 heat units and you are wanting to make an exposure resulting in 250,000 heat units, how long would you have to wait? A) 4 min B) 7 min C) 11 min D) 20 min	C
Which of the following sequences correctly describes the path of blood flow as it leaves the left ventricle?	A) arteries, arterioles, capillaries, venules, veins B) arterioles, arteries, capillaries, veins, venules C) veins, venules, capillaries, arteries, arterioles D) venules, veins, capillaries, arterioles, arteries A
Which of the following radiologic examinations can demonstrate ureteral reflux? A) intravenous urogram B) retrograde pyelogram C) voiding cystourethrogram D) nephrotomogram	C
What angle is formed by the medial sagittal plane and the film in the parieto-orbital projection (Rhese) of the optic canal? A) 90 degrees B) 37 degrees C) 53 degrees D) 45 degrees	C
If the patient is unable to extend his or her head sufficiently for the submentovertex? A) angle CR until it is perpendicular to IOML B) angle CR until it is perpendicular to OML C)CR perpendicular to IR and place sponge behind shoulders	A
When evaluating an open mouth odontiod, you notice that the dens is superimposed by the base of the skull. A) Chin was extended to far B) Chin was tucked to much C) Mouth was not opened wide enough D) This is an acceptable image	A
The inhalation of liquid or solid particles into the nose, throat, or lungs is referred to as A) asphyxia B) aspiration C) atelectasis D) asystole	B
Which of the following radiation-induced conditions is most likely to have the longest latent period? A) leukemia B) temporary sterility C) erythema D) acute radiation lethality	A
Which of the following are methods of limiting the production of scattered radiation? 1. using moderate-ratio grids 2. using the prone position for abdominal exams 3. restricting the field size to the smallest practical size	2 and 3
Greater latitude is available to the radiographer in which of the following circumstances? 1. using high-kVp technical factors 2. using a slow film/screen combination 3. using a low grid ratio	1,2,3
SID affects recorded detail in which of the following ways? A) recorded detail is directly related to SID B) recorded detail is inversely related to SID C) as SID increased recorded detail decreases D) SID is not related to recorded detail	A
A compensating filter is used to A) absorb the harmful photons that contribute only to patient dose B) even out widely differing tissue densities C) eliminate much of the scatter radiation D) improve fluoroscopy	B
Radiographic recorded detail is directly related to 1. SID 2. OID 3. imaging-system speed	1 only
Radiographic recorded detail is inversely related to 1. SID 2. OID 3. screen-speed	2,3
If a 4" collimated field is changed to a 14" collimated field, with no other changes, the radiographic image will possess A) more density B) less density C) more recorded detail D) less recorded detail	A
The contrast improvement factor of a grid will be greatest with A) high-ratio grids with many lines per inch low-ratio grids with many lines per inch C) high-ratio grids with fewer lines per inch D) low-ratio grids with fewer lines per inch	C As increase lines per inch - the lead strips must become thinner - increasing the possibility of energetic scatter passing through
The rear intensifying screen within a cassette may intentionally be made somewhat thicker to A) compensate for photon absorption within the front screen B) improve the resolution capability of the screens C) reduce the amount of light reflectance D) m	A
Which of the following tissues or organs is the most radiosensitive? A) rectum B) esophagus C) small bowel D) central nervous system	C
Factors that are important to evaluate when selecting contrast media include: 1. miscibility 2. potential toxicity 3. viscosity	1,2,3
Possible side effects of an iodinated contrast medium that is administered intravenously include all of the following except: A) warm feeling B) altered taste C) nausea D) hypotension	D distinguish between side effects and adverse effects
The ridge that marks the bifurcation of the trachea into the right and left primary bronchi is the A) root B) carina C) hilus D) epiglottis	B
Aspirated foreign bodies in older children and adults are most likely to lodge in the A) right main bronchus B) left main bronchus C) esophagus D) proximal stomach	A
Place the following anatomic structures in order from anterior to posterior: 1. trachea 2. apex of heart 3. esophagus	C) apex of heart, trachea, esophagus
Examination of the pars petrosae in the posterior profile position (Stenvers) requires 1. the use of the IOML 2. the MSP to be rotated 45 degrees 3. the head rest on the forehead, nose and chin	1,2
Which of the following vertebral group(s) form(s) lordotic curve(s)? 1. Cervical 2 Thoracic 3. Lumbar	1,3
Which of the following positions will most effectively move the gallbladder away from the vertebrae in the asthenic patient? A) LAO B) RAO C) LPO D) Erect	A
n the posterior oblique position of the cervical spine, the intervertebral foramina that are best seen are those A) nearest the film B) furthest from the film C) seen medially D) seen inferiorly	B
Endoscopic retrograde cholangiopancreatography (ERCP) usually involves: 1. cannulation of the hepatopancreatic ampulla 2. introduction of barium into the common bile duct 3. filling all ducts of the biliary tree	1 and 3
The AP projection of the sacrum requires that the central ray be directed 1. 15 degrees cephalad 2. midway between ASIS and the pubic symphysis 3. midline at the level of the greater trochanter	1 and 2
The dose of radiation that will cause a noticeable skin reaction is referred to as the A) linear energy transfer (LET) B) source to skin distance (SSD) C) skin erythema dose (SED) D) source-image distance (SID)	C
Irradiation of water molecules within the body, and their resulting breakdown, is termed A) epilation B) proliferation C) radiolysis D) repopulation	C
Stochastic effects of radiation are those that 1. have a threshold 2. may be described as "all of nothing" effect 3. are late effects	2 and 3
A particular mAs, regardless of the combination of mA and time, will reproduce the same radiographic density. This is a statement of the A) line focus principle B) inverse square law C) reciprocity law D) law of conservation of energy	C
The steeper the straight-line portion of a characteristic curve for a particular film, the 1. slower the film speed 2. higher the film contrast 3. greater the exposure latitude	2
The filament circuit uses what type of transformer? A) Step-up B) Autotransformer C) Step-down D) Falling load	C
Which of the following anatomic parts exhibits the highest subject contrast? A) elbow B) kidney C) esophagus D) lumbar spine	A
The type of shock that is caused by a severe allergic rection is called: A) Hypovolemic shock B) Septic shock C) Neurogenic shock D) Anaphylactic shock	D
Distance and density are governed by what law or rule? A) Reciprocity law B) 15% law C) Inverse square law D) Density maintenance rule	C
Of the following groups of exposure factors, which will produce the greatest radiographic density? A) 200 mA, 500 msec, 36 inch SID B) 400 mA, 0.05 second, 72 inch DIS C) 400 mA, 0.10 second, 72 inch SID D) 200 mA, 100 msec, 36 inch SID	A
Small marks on a radiograph approximately 3.1416 inches apart are called: A) Guide shoe scratches B) Plus-density marking C) Pi lines D) Chemical scratches	C
Poor fixer replenishment will cause: A) Dark films B) Light films C) Milky films D) Greasy films	C
As kVp is decreased: A) Density increases B) Contrast decreases C) Scale of contrast lengthens D) Scale of contrast shortens	D
The section of the stomach where the esophagus enters is called the: A) Rugae B) Pylorus C) Fundus D) Cardiac portion	D
Contraction of the myocardium is termed: A) diastole B) systole C) peristole D) myostol	B
If a transformer has 120 turns of wire on the primary coil, 80 volts in the primary coil and 20 volts in the secondary coil, how many truns of wire must there be in the secondary? A) 30 turns B) 60 turns C) 80 turns D) 160 turns	A
Which of the following is the main component of radiographic noise? A) Quantum mottle B) Structure mottle C) Uniform Mottle D) Random mottle	A
RAdiographic noise increases with an increase in which of the following? A) exposure time B) grid ratio C) phosphor thickness D) image receptor distance	C
On a graph representing the emission spectrum of x-rays produced, the position of the discrete x-ray emission spectrum along the x-axis is best represented by: A) keV B) kVp C) mAs D) target electron binding energy	D
The x-ray emission spectrum is composed of how many separate x-ray emissions spectra? A) One B) Four C) Six D) Unlimited	D
The x-ray emission spectrum represents: A) projectile electron energy B) The x-rays emitted from the x-ray tube C) The atomic mass and number of the target atom D) The electron-binding energy of target material	B
Given a closed loop of wire with no electron flow, an electric current can be induced if: A) a changing magnetic field is present B) a constant magnetic field is present C) no magnetic field is present D) the loop is opened	A
When an electric current is induced by mutual induction, such current flows: A) according to Faraday's law B) according to Lenz's law C) according to Oversted's law D) in the secondary coil	D
The term electromagnetic induction refers to the production of: A) a magnetic field B) a static charge C) an electric current D) electromagnetic radiation	C
In an electric generator: A)a coil of wire is rotated in a magnetic field B)a transformer is charged C)AC is changed to DC D)electrical energy is converted to mechanical energy	A
Radiographic intensifying screen speed increases with increasing: A) atomic mass B) base thickness C) optical density D) phosphor thickness	D
Because x-ray interaction with a phosphor in a screen produces light isotropically: A) a base is required B) a protective layer is required C) the light produced is focused D) the light spreads out in all directions	D
Which of the following principally contributes to the increased speed of rare earth screens? A) conversion efficiency B) high atomic number C) longer wavelength emission D) phosphor thickness	A
What is the approximate percentage of x-rays that are transmitted through a patient? A) 0.1% B) 1% C) 5% D) 10%	B
When kVp is increased with a compensating reduction in mAs, which of the following is reduced? A) optical density B) patient dose C) remnant radiation D)spatial resolution	B
PBL stands for which of the following? A) photon beam level B) photon beam limitation C) photon border level D) positive beam limitation	D
Which of the following techniques will result in the highest patient dose if mAs is changed to maintain optical density? A) 5:1 crossed grid, 70 kVp B) 5:1 crossed grid, 90 kVp C) 10:1 focused grid, 90 kVp D) 12:1 parallel grid, 70 kVp	D
Bedside examination requires a wide range of SIDs. Which of the following parallel grids would be most likely to produce grid cutoff in this type of exam? A) 5:1 B) 8:1 C) 12:1 D) 16:1	D
If the required technique is 5mAs and the mA station selected is 300mA, what is the required exposure time? A) 10ms B) 17ms C) 34ms D) 67ms	B
Referring to the characteristic curve - the generally accepted range of useful optical density on a radiograph is: A) 0.1 - 0.25 B) 0.25 - 2.5 C) 1.0 - 3.0 D) 3.0 - 5.0	B
183. Which of the following is most responsible for radiographic spatial resoulution? A) film graininess B) focal spot size C) SID D) screen mottle	B
When proper radiographic detail cannot be obtained becasue of a large OID, what change in technique may be used to improve detail? A) increase SID B) increase image receptor speed C) reduce mAs D) increase kVp	A
a 120 X 120 matrix will consisst of how many pixels? A) 120 B) 240 C) 625 D) 14,400	D
Increasing the temperature of the x-ray tube filament: A) controls voltage rectification B) increases mA C) increases x-ray energy D) reduces anode heat-loading	B
If saturation is achieved and the filament current is fixed, tube current A) decreases with use B) falls with increasing kVp C) remains fixed D) rises with increasing exposure time	C
The number of volts required to cause a current of 30A in a circuit having a resistance of 3 ohm is: A) 5 V B) 40 V C) 90 V D) 200 V	C
During a fluoroscopic examination, the milliamperage is A) less than 5 B) 10 to 20 C) 50 to 75 D) 100 to 500	A
Which of the following personnel monitoring devices used in diagnostic radiography is considered to be the most sensitive and accurate? A) TLD B) film badge C) OSL D) pocket dosimeter	C
T-tube cholangiography is performed A) preoperatively B) during surgery C) postoperatively D) with a Chiba needle	C
Accurate operation of the AEC device is dependent on 1. thickness and density of object 2. positioning of the object with respect to the photocell 3. beam restriction	2 and 3
The maximum cumulative whole-body exposure that is allowed for a 28-year-old occupational worker is: A) 1.08 Sv (108 rem) B) 0.88 Sv (88 rem) C) 0.28 Sv (28 rem) D) 0.028 Sv (2.8 rem)	C
Which of the following will occur as a result of decreasing the anode target angle?1. anode heel effect will be less pronounced2. effective focal spot size will decrease3. greater photon intensity toward the cathode side of the x-ray tube	2 and 3
Changes in window width in digital imaging result in changes in: A) contrast B) density C) resolution D) distortion	A

What is straight

The straight-line portion The term straight-line portion refers to the section of the curve between 2 and 3 on the diagram. In this portion density increases by a constant factor upon increases in exposure. There is a linear relationship between density and log-exposure (Log E).

What is H and D curve in radiography?

Definition. A graph in which the density of the photographic film (vertical axis) is plotted against the logarithm of the relative exposure (horizontal axis), to illustrate the photographic characteristics of an emulsion (e.g. on an x-ray film).

Which area on the characteristic curve represents high exposure levels?

The shoulder region represents the area of high exposure levels. The optical density in the shoulder region is > 2.5. Dmax is the maximum density the film is capable of recording. A radiograph with optical densities in the region of the toe or shoulder furnishes an image with interior contrast.

Which region of the characteristic curve represents the inherent density in the film?

 The curve has four regions namely base plus fog, toe region, straight-line portion and shoulder region. Dmax represents the maximum density.  The base plus fog region represents the inherent density or the initial film density before exposure to x-ray photons.

The steeper the straight-line portion of a characteristic curve for a particular film, the

What is straight

What is H and D curve in radiography?

Which area on the characteristic curve represents high exposure levels?

Which region of the characteristic curve represents the inherent density in the film?

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