Explanation:

Indirect contact involves transmission of microorganisms via airborne contamination, fomites, and vectors. Airborne precaution requires the patient to wear a mask to avoid thespread of acid-fast bacilli (in bronchial secretions of TB patients) or other pathogens during
coughing. If the patient is unable or unwilling to wear a mask, the radiographer must wear one.
The radiographer should wear gloves, but a gown is required only if flagrant contamination is likely. Patients infected with airborne precaution require a private, specially ventilated (negative pressure) room. A private room is indicated for all patients on droplet precaution, that is, diseases transmitted via large droplets expelled from the patient while speaking, sneezing, or coughing. The pathogenic droplets can infect others when they come in contact with mouth or nasal mucosa or conjunctiva. Rubella (“German measles”), mumps, and influenza are among the diseases spread by droplet contact; a private room is required for the patient, and healthcare practitioners must use gown and gloves

Explanation:

In the photoelectric effect, a relatively low-energy incident photon uses all of its energy to eject an inner-shell electron, leaving a vacancy. An electron from the next shell will drop to fill the vacancy, and a characteristic ray is given up in the transition. This type of interaction is more harmful to the patient, as all the photon energy is transferred to tissue

Explanation:

The exposed CR cassette is placed into the CR scanner reader, where the PSP plate is automatically removed. The latent image appears as the PSP is scanned by a narrow highintensity
helium–neon laser to obtain the pixel data. As the plate is scanned in the CR reader,it releases a violet light—a process referred to as photostimulated luminescence.
The luminescent light is converted to electrical energy representing the analog image.The electrical energy is sent to an analog-to-digital converter (ADC) where it is digitized becomes the digital image that is eventually displayed (after a short delay) on a high-resolutionmonitor and/or printed out by a laser printer. The digitized images can also be manipulated in postprocessing, electronically transmitted, and stored/archived

Explanation:

The posteroanterior (PA) axial projection (Haamethod/nuchofrontal projection) of the skull requires that the central ray be angled 25-degree cephalad to the perpendicular
orbitomeatal line (OML). This position is used to demonstrate the occipital bone in kyphotic
patients and other patients who are unable to assume the AP recumbent position. If positioned accurately, the dorsum sella and posterior clinoid processes will be demonstrated within the foramen magnum. If the central ray is angled excessively, the posterior aspect of the arch of
C1 will appear in the foramen magnum

Explanation:

A profile view of the glenoid fossa can be obtained in the anteroposterior (AP) oblique projection (left posterior oblique [LPO] or right posterior oblique [RPO], Grashey method).
In the anatomic position, the bony glenoid fossa is seen to project posteriorly and laterally
approximately 40 degrees. Therefore, if the shoulder is positioned with the body rotated 35- to 45-degree toward the affected side, the glenoid fossa will be placed parallel with the CR(perpendicular to the image receptor) and a profile view of the fossa is obtained.

Explanation:

Nonstochastic effects are somatic effects that are predictable, threshold responses; that is, a certain quantity of radiation must be received before the effect occurs, and the greater
the dose the more severe the effect. Examples of nonstochastic effects are erythema, blood changes, cataract formation, and epilation. Stochastic effects of radiation are nonthreshold and randomly occurring. Examples of stochastic effects include carcinogenesis and genetic effects.
The chance of occurrence of stochastic effects is directly related to the radiation dose; that is,
as radiation dose increases there is a greater likelihood of genetic alterations or development
of cancer

Explanation:

Some chemical agents used in health care facilities function to kill pathogenic microorganisms,
while others function to inhibit the growth/spread of pathogenic microorganisms. Germicides and disinfectants are used to kill pathogenic microorganisms, and antiseptics (like alcohol) are used to stop their growth/spread. Sterilization is another associated term and refers to killing of all microorganisms and their spores

Explanation:

Tomography is a procedure that uses reciprocal motion between x-ray tube and image receptor-to-image structures at a particular level in the body, while blurring everything above
and below that level. The thickness of the level visualized can be varied by changing the tube angle (amplitude). In general, the greater the tube angle, the thinner the sectioimaged.Thinner sections may be used for imaging small or intricate structures

Explanation:

As blood pulsates through the arteries, a throb can be detected. This throb or pulse can be readily palpated where the arteries are superficial (examples are wrist, groin, neck, and posterior surface of the knee). The apical pulse can be detected with a stethoscope

Explanation:

The image intensifier in mobile fluoroscopic (“C” arm) equipment has the same function as the image intensifier in fixed equipment; that is, it brightens the x-ray image so that it be viewed in a room having normal lighting. The TV camera/CCtransmits the fluoroscopic image from the output phosphor of the image intensifier to the TV monitor for viewing. Mobile fluoroscopes/”C” arms have no spot-film device, although they frequently have features such as “last image hold” and capacity for digital recording

Explanation:

Inside the CR cassette is the photostimulable phosphor (PSP) image plate, sometimes referred to simply as an image plate or IP. This PSP or IP with its layer of europium-activated barium fluorohalide serves as the image receptor as it is exposed in the traditional manner and receives the latent image. The PSP can store the latent image for several hours; after approximately 8 hours noticeable image fading will occur. Once the CR cassette is placed into the CR processor (scanner or reader), the PSP plate is automatically removed. The latent image on the PSP is changed to a manifest image as it is scanned by a narrow high-intensity helium–neon laser to obtain the pixel data. As the plate is scanned in the “reader,” it releases a violet light—a process referred to as photo- (or light) stimulated luminescence

Explanation:

The knee (tibiofemoral joint) is the largest joint of the body, formed by the articulation of the femur and tibia. However, it actually consists of three articulations: the patellofemoral
joint, the lateral tibiofemoral joint (lateral femoral condyle with tibial plateau), and the medial
tibiofemoral joint (medial femoral condyle with tibial plateau). Although the knee is classified as a synovial (diarthrotic) hinge-type joint, the patellofemoral joint is actually a gliding joint, and the medial and lateral tibiofemoral joints are hinge type

Explanation:

When performing gastrointestinal (GI) radiography, the position of the stomach may vary depending on the respiratory phase, the body habitus, and the patient position. Inspiration
causes the lungs to fill with air and the diaphragm to descend, thereby pushing the abdominal contents downward. On expiration, the diaphragm will rise, allowing the abdominal organs to ascend. Body habitus is an important factor in determining the size and shape of the stomach. An asthenic patient may have a long, J-shaped stomach, while the stomach may be transverse
on a hypersthenic patient. The body habitus is an important consideration in determining
the positioning and placement of the image receptor. The patient position can also alter the position of the stomach. If a patient turns from the right anterior oblique (RAO) position into the anteroposterior (AP) position, the stomach will move into a more horizontal position. Although
the cardiac sphincter and the pyloric sphincter are relatively fixed, the fundus is quite mobile and will vary in position

Explanation:

Ribs below the diaphragm are best demonstrated with the diaphragm elevated. This is accomplished by placing the patient in a recumbent position and by taking the exposure at
the end of exhalation. Conversely, the ribs above the diaphragm are best demonstrated  the diaphragm depressed. Placing the patient in the erect position and taking the exposure at the end of deep inspiration accomplishes this

Explanation:

Protective barriers are classified as either primary or secondary. Primary barriers protect from the useful, or primary, x-ray beam and consist of a certain thickness of lead. They
are located anywhere the primary beam can possibly be directed, for example, the walls of the x-ray room. The walls of the x-ray room usually require 1/16-inch (1.5-mm) thickness of lead 7-feet high. Secondary barriers protect from secondary (scattered and leakage) radiation.
Secondary barriers are control booths, lead aprons and gloves, the wall of the x-ray room above
7 feet. Secondary barriers require much less lead than primary barriers

Explanation:

Syncope, or fainting, is a result of a drop in blood pressure caused by insufficient blood (oxygen) to the brain. The patient should be helped into a dorsal recumbent position
with feet elevated to facilitate blood flow to the brain

Explanation:

The phenomenon in which the radiographic information recorded on the PSP/IP upon exposure to x-rays decreases with the elapsed time until it is read by the scanner/reader
is termed fading. This occurs because the photoelectrons generated by x-ray excitation upon exposure of the photostimulable phosphor are thermally released over time and therefore are unable to contribute to photostimulated luminescence upon scanning/reading. Luminescence
decreases by approximately 25% within 8 hours of exposure. The greater the elapsed time and
the greater the environmental temperature, the greater will be the degree of fading

Explanation:

According to Bergoni´e and Tribondeau, the most radiosensitive cells are undifferentiated, rapidly dividing cells such as lymphocytes, intestinal crypt (of Lieberk¨uhn) cells, and spermatogonia. Liver cells are among the types of cells that are somewhat differentiated and capable of mitosis. These characteristics render them somewhat radiosensitive. Muscle cells, as well as nerve cells and red blood cells, are highly differentiated and do not divide. Therefore, in order of decreasing sensitivity (from least to greatest sensitivity), the cells are intestinal crypt cells, liver cells, and muscle cells.

Explanation:

Distortion is caused by improper alignment of the tube, body part, and image receptor.Anatomic structures within the body are rarely parallel to the image receptor in a simple recumbent position. In an attempt to overcome this distortion, we position the part to be parallel with the image receptor, or angle the central ray to “open up” the part. Examples of this technique are obliquing the pelvis to place the ilium parallel to the image receptor, or angling the central ray cephalad to “open up” the sigmoid colon

Explanation:

Tissue is most sensitive to radiation exposure when in an oxygenated condition.Anoxic refers to a general lack of oxygen in tissue; hypoxic refers to tissue with little oxygen.
Anoxic and hypoxic tumors are typically avascular (with little or no blood supply) and therefore more radioresistant

Explanation:

Oral administration of barium sulfate is used to demonstrate the upper digestive system, esophagus, fundus, body and pylorus of the stomach, and barium progression through the small bowel. The large bowel, including sigmoid colon, is usually demonstrated via rectal administration of barium

Explanation:

Tissue is most sensitive to radiation exposure when in an oxygenated condition. Anoxic refers to a general lack of oxygen in tissue; hypoxic refers to tissue with little oxygen. Anoxic and hypoxic tumors are typically avascular (with little or no blood supply) andtherefore more radioresistant

Explanation:

The ability of x-ray photons to penetrate a body part has a great deal to do with the composition of that part (e.g., bone vs. soft tissue vs. air) and the presence of any pathologic
condition. Pathologic conditions can alter the normal nature of the anatomic part. Some conditions
such as osteomalacia, fibrosarcoma, and paralytic ileus (obstruction) result in a decreasein body tissue density. When body tissue density decreases, x-rays will penetrate the tissues more readily, that is, more x-ray penetrability. In conditions such as ascites, where body tissue density increases as a result of accumulation of fluid, x-rays will not readily penetrate the body tissues, that is, less x-ray penetrability

Explanation:

The image intensifier’s input phosphor receives the remnant beam from the patient and converts it to a fluorescent light image. To maintain resolution, the input phosphor is made of cesium iodide crystals. Cesium iodide is much more efficient in this conversion process than
was the phosphor previously used, zinc cadmium sulfide. Calciutungstate was the phosphor used in cassette-intensifying screens for many years prior to the development of rare earth
phosphors such as gadolinium oxysulfide

Explanation:

Hysterosalpingography may be performed for demonstration of uterine tubal patency, mass lesions in the uterine cavity, and uterine position. Although hysterosalpingography is often performed to check tubal patency, the uterine anatomy, position, and morphology are exhibited. Additionally, polyps, fibroids, or space occupying lesions within the uterus are well demonstrated

Explanation:

Double-contrast studies of the stomach or large intestine involve coating the organ with a thin layer of barium sulfate, and then introducing air. This permits seeing through the
organ to structures behind it, and most especially allows visualization of the mucosal lining of the organ. A barium-filled stomach or large bowel demonstrates position, size, and shape of the organ, and any lesion that projects out from its walls, such as diverticula. Polypoid lesions,
which project inward from the wall of an organ, may go unnoticed unless a double-contrast examination is performed

Explanation:

The intensity or exposure rate of radiation at a given distance from a point source is inversely proportional to the square of the distance. This is the inverse square law of radiation and is expressed in the following equation:
I 1
I 2
= D2
2
D2
1
Substituting known values:
40 mR/h
x mR/h
= 25
9
25x = 360
x = 14.4 mR/h, therefore 7.2 mR in 30 minutes

Explanation:

The medical suffix plasia refers to development, formation, growth, or proliferation. The suffix denoting embryonic is blast. Condition is indicated by the suffix osis. The suffix kinesia is used to refer to motion or movement

Explanation:

The anteroposterior (AP) axial projection (Towne method) of the skull is used to demonstrate the occipital bone. The skull is positioned AP and the CR is directed caudally.
This serves to project the anterior structures inferiorly and away from superimposition on the occipital bone. The frontal bone is best demonstrated in the PA projection; the facial bones in the parietoacanthial (Waters) position. The sphenoid bone can be seen in the lateral and basal projections

Explanation:

The mediastinum is the space between the lungs that contains the heart, great vessels, trachea, esophagus, and thymus gland. It is bound anteriorly by the sternum and posteriorly by the vertebral column and extends from the upper thorax to the diaphragm

Explanation:

Because the established dose-limit formula guideline is used for occupationally exposed
persons 18 years of age and older, guidelines had to be established in the event a student entered the clinical component of a radiography educational program prior to age 18 years.The guideline states that the occupational dose limit for students younger than 18 years is 0.1rem (100 mrem or 1 mSv) in any given year. It is important to note that this 0.1 rem is included in the 0.5 rem dose limit that allowed the student as a member of the general public

Explanation:

Proper body mechanics includes a wide base of support. The base of support is the part of the body in touch with the floor or other horizontal plane. The center of gravity is the
midpoint of the pelvis or lower abdomen, depending on body build. The line of gravity is the abstract line passing through the center of gravity, vertically. Proper body mechanics can help prevent painful back injuries by making proficient use of the muscles in the arms and legs

Explanation:

The “scapular Y” refers to the characteristic Y formed by the body of the scapula, acromion, and coracoid processes. The patient is positioned in a posteroanterior (PA) oblique position—a right anterior oblique (RAO) or left anterior oblique (LAO), depending on which is the affected side. The midcoronal plane is adjusted approximately 60 degrees to the image.

Explanation:

The automatic exposure control (AEC) automatically terminates the exposure when the proper density has been recorded on the image receptor. The important advantage of the
phototimer, then, is that it can accurately duplicate radiographic densities. It is very useful in
providing accurate comparison in follow-up examinations, and in decreasing patient exposure
dose by decreasing the number of “retakes” because of improper exposure. The AEC automatically
adjusts the exposure required for body parts having different thicknesses and densities.
Remember that proper functioning of the AEC depends on accurate positioning by the radiographer.
The correct ionization chamber(s) must be selected, and the anatomic part of interest must completely cover the ionization chamber to achieve the desired density. If collimation is inadequate, and a field size larger than the part is used, excessive scattered radiation from the body or tabletop can cause the AEC to terminate the exposure prematurely, resulting in anunderexposed radiograph
underexposed radiograph

Explanation:

Chromosome aberration, cell death, and malignant disease are major effects of deoxyribonucleic acid (DNA) irradiation, often as a result of abnormal metabolic activity. If the damage happens to the DNA of a germ cell, the radiation response may not occur until one or more generations later.

Explanation:

Voltage ripple refers to the percentage drop from maximum voltage each pulse of current experiences. In single-phase rectified equipment, the entire pulse (half-cycle) is used; therefore, there is first an increase to maximum (peak) voltage value and a subsequent decrease to zero potential (90-degree past peak potential). The entire waveform is used; if 100 kV (kilovolts) were selected, the actual average kilovoltage output would be approximately 70.
Three-phase rectification produces almost constant potential with just small ripples (drops) in maximum potential between pulses. Approximately a 13% voltage ripple (drop from maximum value) characterizes the operation of three-phase, six-pulse generators. Three-phase, 12-pulse generators have approximately a 4.0% voltage ripple

Explanation:

Obtaining a complete and accurate history from the patient for the radiologist is an important aspect of a radiographer’s job. Both subjective and objective data should becollected. Objective data include signs and symptoms that can be observed, such as a cough, a lump, or elevated blood pressure. Subjective data relate to what the patient feels, and to what
extent. A patient may experience pain, but is it mild or severe? Is it localized or general? Does
the pain increase or decrease under different circumstances? A radiographer should explore this with a patient and document additional information on the requisition for the radiologist

Explanation:

Computed radiography (CR) uses special phosphor plates inside image plates (IPs) to record the radiologic image. No film is used, hence the term filmless radiography. The IP is exposed just like a conventional screen–film cassette. Upon exposure, a latent image is produced on the photostimulable phosphor (PSP), which is located inside the IP. The IP is placed in the CR reader, and the PSP is automatically removed.

Explanation:

There are two types of distortion: size and shape. Shape distortion relates to the alignment of the x-ray tube, the part to be radiographed, and the image receptor. There are two kinds of shape distortion: elongation and foreshortening. Size distortion is magnification and is related to the object-to-image-receptor distance (OID) and source-to-image-receptor
distance (SID). Magnification can be reduced by either increasing the SID or decreasing the OID. However, an increase in SID must be accompanied by an increase in mAs (milliampereseconds)
to maintain density. It is therefore preferable, in the interest of exposure time, to reduce OID whenever possible

Explanation:

Three times a day is indicated by the abbreviation TID. The abbreviation QID means four times a day. Every hour is represented by QH, and PC means after meals

Explanation:

As kV is increased, more high-energy photons are produced and the overall energy of the primary beam is increased. Photon energy is inversely related to wavelength; that is,as photon energy increases, wavelength decreases. An increase in milliamperage serves to
increase the number of photons produced at the target, but isunrelated to their energy

Explanation:

The cervical intervertebral foramina lie 45 degrees to the midsagittal plane and 15 to 20 degrees to a transverse plane. When the posterior oblique position (LPO, RPO) is used, the cervical intervertebral foramina demonstrated are those further from the image receptor.There is therefore some magnification of the foramina. In the anterior oblique position (LAO,
RAO), the foramina disclosed are those closer to the image receptor

Explanation:

Proper alignment of the x-ray tube, body part, and image receptor is required to avoid image distortion in the form of foreshortening or elongation. Foreshortening will usually result when the part is out of alignment. Elongation is often a result of angulation of the x-ray tube.
Grid lines or grid cutoff will occur when the grid itself is off center or is not in alignment with the x-ray tube

Explanation:

Image “fading” will occur if there is delay in reading the PSP. This is because after a time, trapped photoelectrons are released from the “color center” and are therefore unable to participate in PSL. PSL intensity decreases in the interval between x-ray exposure and the
image reading process. If the exposed PSL is not delivered to the reader/processor for 8 hours,PSL decreases by approximately 25%. Fading also increases as environmental  temperature increases. It is recommended that the PSP be scanned in the reader at right angles to grid line direction to avoid/reduce aliasing artifacts

Explanation:

Single-screen cassettes are made to be used with single emulsion film, such as inmammography. The single fluorescing screen is adjacent to, and exposes, the single emulsion.
If double emulsion (duplitized) film is placed in a single screen cassette, it will receive only one-half the intended exposure and the resulting image will exhibit decreased density

Explanation:

Most laser film is sensitive to both the Wratten 6B and the GBX safelight filters. Laser film will fog if handled under these safelight conditions. Most laser film is loaded into a film
magazine in total darkness. Processing temperatures are the same for laser film as for regular
x-ray film

Explanation:

Radiographic contrast is described as the difference between densities, or scale of grays, in the radiographic image. Because the function of grids is to collect scattered radiation,
they serve to shorten the scale of contrast. Beam restrictors function to limit the x-ray field size, thereby reducing the production of scattered radiation, and shorten the scale of contrast.
Focal spot size is one of the geometric factors affecting recorded detail and has no effect on the scale of contrast. It is the function of radiographic contrast to make details visible. The sum of subject contrast and film contrast equals radiographic contrast

Explanation:

A pulse oximeter is used to measure a patient’s pulse rate and oxygen saturation level.
A stethoscope and a sphygmomanometer are used together to measure blood pressure. The
first sound heard is the systolic pressure and the normal range is 110 to 140 mmHg. When no
more sound is heard, the diastolic pressure is recorded. The normal diastolic range is 60 to 90  mmHg. Elevated blood pressure is called hypertension. Hypotension, low blood pressure, is not of concern unless it is caused by injury or disease; in that case, it results in shock

Explanation:

The development of male and female reproductive stem cells has important radiation protection implications. Male reproductive stem cells reproduce continuously. However, the female reproductive stem cells develop only during fetal life; women are born with all the reproductive cells they will ever have. It is exceedingly important to shield children wheneverpossible, as they have their reproductive futures ahead of them

Explanation:

Insufficient milliamperage and/or exposure time will result in lack of radiographic density. Insufficient kV (kilovolts) results inunderpenetration and excessive contrast. Insufficient source-to-image-receptor distance (SID), however, will result in increased exposure rate and  radiographic overexposure

Explanation:

The quantity of x-ray photons produced at the target is the function of mAs. The quality(wavelength, penetration, energy) of x-ray photons produced at the target is the function of kV.The kV also has an effect on exposure rate, because an increase in kV will increase the number of high-energy x-ray photons produced at the target. Exposure rate decreases with an increase in source-to-image-receptor distance (SID)

Explanation:

Anemia is a blood condition characterized by a decreased number of circulating red blood cells and decreased hemoglobin, and has many causes. Adequate hemoglobin is required to provide oxygen to the body. Anemia is treated according to its cause. Hematuria is the term used to describe blood in the urine and is unrelated to anemia

Explanation:

In manual processing there is a stop bath between the developer and fixer solutions that serves to remove developer solution from the film surface and stop the development
process. Automatic processing has no stop bath; film travels directly from the developer into the fixer solution. However, the processor’s transport rollers serve to squeeze the solution from the film surface, and the acid fixer stops the (alkaline) development process. Guide shoes are found in turnaround assemblies and help direct the film as it bends from one direction to another 

Explanation:

The greatest effect of, and response to, irradiation is brought about by a large dose of radiation, to the whole body, delivered all at one time. Whole-body radiation can depress
many body functions. With a fractionated dose, the effects would be less severe because the body would have an opportunity to repair between doses

Explanation:

In the anteroposterior (AP) projection, the proximal fibula is at least partially superimposed on the lateral tibial condyle. Medial rotation of 45 degrees will “open” the proximal tibiofibular articulation. Lateral rotation will obscure the articulation even more 

Explanation:

Some chemical agents used in health care facilities function to kill  pathogenic microorganisms,while others function to inhibit the growth/spread of pathogenic microorganisms.Germicides and disinfectants are used to kill pathogenic microorganisms and antiseptics (like alcohol) are used to stop their growth/spread. Sterilization is another associated term and refers to killing of all microorganisms and their spores 

Explanation:

Epinephrine (Adrenalin) is the vasopressor used to treat ananaphylactic reaction orcardiac arrest. Nitroglycerin is a vasodilator. Hydrocortisone is a steroid that may be used to treat bronchial asthma, allergic reactions, and inflammatory reactions. Digitoxin is used to treat
cardiac fibrillation 

Explanation:

Grids are used in radiography to absorb scattered radiation before it reaches the image receptor, thus improving radiographic contrast. Contrast obtained with a grid compared to contrast without a grid is termed contrast improvement factor. The greater the percentage of scattered radiation absorbed compared to absorbed nonscattered radiation, the greater the“selectivity” of the grid. If a grid absorbs an abnormally large amount of primary radiation because of improper centering, tube angle, or tube distance, grid cutoff occurs

Explanation:

Changes in hormone levels affect changes in the glandular tissue of the breast. For example, breast tissue changes are seen during breast development, during pregnancy and
lactation, and during menopause. Women at higher risk of developing breast cancer includethose having had early menses (before age 12 years), late menopause (after age 52 years), andnulliparity (no full- or late-term pregnancies). Risks other than hormonal include family history
and age 

Explanation:

The bony walls of the orbit are thin, fragile, and subject to fracture. A direct blow to the eye results in a pressure that can cause fracture. That fracture is usually to the orbital floor (inferior aspect of the bony orbit). Because the fracture results from increased pressure within the eye, it is referred to as a “blowout” fracture.

Explanation:

Histogram appearance can be affected by a number of things. Positioning and centering accuracy can have a significant effect on histogram appearance  Otherfactors affecting histogram appearance include selection of the correct processing algorithm (e.g., chest vs. femur), changes in scatter, SID, OID, and collimation. In short, anything that affects scatter and/or dose. Another factor affecting histogram appearance is delay in processing from time of exposure. Processing delay can result in fading of the image

Explanation:

When the barium fluorohalide absorbs x-ray energy, electrons are released and they divide into two groups. One electron group initiates immediate luminescence during the excited state of Eu2+. The other electron group becomes trapped within the phosphor’s halogen ions, forming a “color center.” These are the phosphors that ultimately form the radiographic image because when exposed to a monochromatic laser light source these phosphors emit polychromatic light, termed photostimulated luminescence (PSL).
The PSP layer (or Storage Phosphor Screen/SPS) can store its latent image for several hours, however, after approximately 8 hours noticeable image fading will occur. The Europium activator is important for the storage characteristic of the PSPs; it also has  function similar to the sensitization specks within film emulsion—without europium, the image  will not become manifest

Explanation:

Late, long-term, effects of radiation can occur in tissues that have survived a previous irradiation months or years earlier. These late effects, such as carcinogenesis and genetic effects are “all-or-nothing” effects—either the organism develops cancer or it does not. Most late effects
do not have a threshold dose; that is, any dose, however small, theoretically can induce an effect. Increasing that dose will increase the likelihood of the occurrence, but will not affect its
severity; these effects are termed stochastic. Nonstochastic effects are those that will not occur below a particular threshold dose, and that increase in severity as the dose increases

Explanation:

The patient, as the first scatterer, is the most important scatterer. At 1 m from the patient, the intensity of the scattered beam is 0.1% of the intensity of the primary beam.Compton scatter emerging from the patient is almost as energetic as the primary beam entering the patient

Explanation:

Computed tomography (CT) and magnetic resonance imaging (MRI) are two common examples of digital imaging. Special equipment is also available for digital radiography
(DR), or computed radiography (CR): images produced by either a fan-shaped x-ray beam received by linearly arrayed radiation detectors or a traditional fan shaped x-ray beam received by a light stimulated phosphor plate. Digital images can also be obtained in digital subtraction
angiography (DSA), nuclear medicine, and diagnostic sonography. Analog images are conventional images that can be converted to digital images with a device called a digitizer.
Pluridirectional tomography refers to conventional tomographic equipment that is capable of several x-ray tube movements

Explanation:

After exposure, the IP is placed into the CR reader where the PSP screen is automatically removed, moved at a constant speed, and scanned by a narrow high-intensity helium–neon (infrared) laser or a solid state laser to obtain the pixel data. The appropriate wavelength is absorbed by the “color center” and the electrons trapped there, causing PSL to occur during the excited state of Eu2+.
The phosphors are activated by a monochromatic laser light, however, PSL is a different color (bluish-purple, blue-green, etc.). These two lights (PSL and laser) must not interfere with each other. To improve the image SNR, the PSL (carrying the x-ray image) must be a different
wavelength/color than, and physically separate from, the laser excitation light. An optical filter/beam-shaping optics is used that permits transmission of the PSL, but attenuates the laser light; this filter/beam-shaper is mounted in front of a PMT.
The PMT or photodiode detects the PSL and converts it to electrical signals that are sent to an ADC where it becomes the digital image displayed on a high-resolution monitor. The
digitized images can also be manipulated in postprocessing, electronically transmitted, and
stored/archived

Explanation:

Angina pectoris is a spasmodic chest pain frequently caused by oxygen deficiency in the myocardium. The pain often radiates down the left arm and up to the left jaw. Angina pectoris attacks are frequently associated with exertion or emotional stress in individuals with coronary artery disease. Pain may be relieved with a vasodilator such as nitroglycerin given sublingually or transdermally. Digitalis is used to treat congestive heart failure. Dilantin is used in the control of seizure disorders, and Tagamet is used to treat duodenal ulcers

Explanation:

In the parieto-orbital projection (Rhese method), the patient is prone with the acanthiomeatal  line perpendicular to the image receptor. The head rests on the forehead, and chin, and the MSP should form 53 degrees with the image receptor (37 degrees with the central ray). Radiographically, the optic canal should appear in the lower outer quadrant of the orbit. Incorrect rotation of the MSP results in lateral or medial displacement, and incorrect
positioning of the baseline results in longitudinal displacement of the optic canal

Explanation:

Radiographic contrast is described as the difference between densities in the radiographic image. It is the function of radiographic contrast to make details visible. Radiographs
exhibiting many shades of gray are said to possess long-scale, or low, radiographic contrast; that is, there are many grays, and there is only little difference between the various shades of gray.Conversely, radiographs exhibiting few shades of gray are said to possess short-scale, or high,
radiographic contrast. These images have a very noticeable difference between radiographic densities 

Explanation:

Injectable medications are available in two different kinds of containers. An ampuleusually holds a single dose of medication. A vial is a small bottle that holds several doses of the medication. The term bolus is used to describe an amount of fluid to be injected. A carafe is a narrow-mouthed container not likely to be used for medical purposes.

Explanation:

An increase in kilovoltage (photon energy) will result in a greater number (i.e., exposure rate) of scattered photons (Compton interaction). These scattered photons carry no useful information and contribute to radiation

Explanation:

The distal humerus articulates with the proximal radius and ulna to form the elbow joint. At its proximal end, the ulna presents the olecranon process, found at the proximal and
posterior end of the semilunar (trochlear) notch. The coronoid process is seen at the distal and
anterior end of the semilunar notch. Specifically, the semilunar notch of the ulna articulates with the trochlea of the distal medial humerus. The capitulum is lateral to the trochlea and articulates with the radial head

Explanation:

The patient is the most important radiation scatterer during both radiography and
fluoroscopy. In general, at 1 m from the patient, the intensity is reduced by a factor of 1000, to approximately 0.1% of the original intensity. Successive scatterings can render the intensity to unimportant levels

Explanation:

The sacroiliac joints angle posteriorly and medially 25 degrees to the median sagittal plane (MSP). Therefore, to demonstrate the sacroiliac joints with the patient in the anteroposterior (AP) position, the affected side must be elevated 25 degrees. This places the joint space perpendicular to the image receptor and parallel to the central ray. Therefore, the left posterioroblique (LPO) position will demonstrate the right sacroiliac joint and the right posterior oblique(RPO) position will demonstrate the left. When  performed with the patient posteroanterior (PA), the unaffected side will be elevated 25 degrees

Explanation:

Magnification is part of every radiographic image. Anatomic parts within the body are at various distances from the image receptor and therefore have various degrees of magnification.
The formula used to determine amount of image magnification is:

Image size/Object size = SID/SOD

x/3= 36″SID/32″SOD(SOD= SID-OID)

32x= 108

x = 3.37″ image width

Explanation:

Magnification is part of every radiographic image. Anatomic parts within the body are at various distances from the image receptor and therefore have various degrees of magnification.
The formula used to determine amount of image magnification is:

Image size/Object size = SID/SOD

x/3= 36″SID/32″SOD(SOD= SID-OID)

32x= 108

x = 3.37″ image width

Explanation:

Sternoclavicular joints should be performed posteroanterior (PA) whenever possible to keep OID to a minimum. The oblique position (approximately 15 degrees) opens the joint closest to the image receptor. The erect position may be used, but is not required. Weightbearing images are not recommended

Explanation:

The greater and lesser tubercles are prominences on the proximal humerus separated by the intertubercular (bicipital) groove. The anteroposterior (AP) projection of the
humerus/shoulder places the epicondyles parallel to the image receptor and the shoulder in external rotation and demonstrates the greater tubercle in profile. The lateral projection of the humerus places the shoulder in extreme internal rotation with the epicondyles perpendicular
to the image receptor and demonstrates the lesser tubercle in profile

Explanation:

Radiographic examinations of the large bowel generally include the anteroposterior (AP) or posteroanterior (PA) axial position to “open” the S-shaped sigmoid colon, the lateral position especially for the rectum, and the left anterior oblique (LAO) and right anterior oblique (RAO) (or left posterior oblique [LPO] and right posterior oblique [RPO]) to “open” the colic flexures. Left and right decubitus positions are usually employed only in double-contrast barium enemas to better demonstrate double contrast of the medial and lateral walls of the ascending and descending colon

Explanation:

Protective or “reverse” isolation is used to keep the susceptible patient from becoming infected. Patients who have suffered burns have lost a very important means of protection, their skin, and therefore have increased susceptibility to bacterial invasion. Patients whose immune systems are depressed lose the ability to combat infection, and hence are more susceptible to infection. Active tuberculosis requires airborne precautions 

Explanation:

Conventional screen–film images can be scanned and digitized by a special machine called a film digitizer. Interpretation of digital images is made from the CRT display monitor; this is referred to as “soft copy display.” “Hard copies” can be made with a laser printer. A laser camera records the displayed image by exposing a film with laser light; it can also record several images on one film. The laser printer is connected for processing of the images

Explanation:

Because lead content increases as grid ratio increases, more scattered radiation (and nonscattered remnant radiation) is absorbed before reaching the image receptor. There are, therefore, fewer x-ray photons interacting with the image receptor, with a resulting decrease in optical/radiographic density as grid ratio increases. Scale of contrast would decrease withan increase in grid ratio

Explanation:

Patients who are able to cooperate are usually able to control voluntary motion if they are provided with an adequate explanation of the procedure. Once patients understand
what is needed, most will cooperate to the best of their ability (by suspending respiration and holding still for the exposure). Certain body functions and responses, such as heart action,
peristalsis, pain, and muscle spasm, cause involuntary motion uncontrollable by the patient. The best way to control involuntary and voluntary motion is by always selecting the shortest possible exposure time. Voluntary motion may also be minimized by careful explanation, immobilization, and (as a last resort and only in certain cases) restraint

Explanation:

The manubrial or jugular notch is the depression on the superior border of the manubrium and is located at the level of the third thoracic vertebra. The vertebra prominens is at the level of the seventh cervical vertebra 

Explanation:

An AEC (automatic exposure control) is calibrated to produce radiographic densities as required by the radiologist for interpretation purposes. Once the part being radiographed has been exposed to produce the required optical density, the AEC automatically terminates the exposure. The manual timer should be used as a backup timer should the AEC fail to terminate the exposure, thus protecting the patient from overexposure and the x-ray tube from excessive heat load. Circuit breakers and fuses are circuit devices used to protect circuit elements from overload. In case of current surge, the circuit will be broken (opened), thus preventing equipment damage. A rheostat is a type of variable resistor

Explanation:

The cassette is used to support the intensifying screens and x-ray film. It should be strong and provide good screen–film contact. The cassette front should be made of a sturdy
material with a low atomic number, because attenuation of the remnant beam is undesirable. Bakelite (the forerunner of today’s plastics) and magnesium (the lightest structural metal) are the most commonly used materials for cassette fronts. The high atomic number of tungsten makes it inappropriate as a cassette front material

Explanation:

The female pelvis differs from the male pelvis in that it is more shallow and its bones are generally lighter and more delicate . The pelvic outlet is wider and more circular in the female, the ischial tuberosities and acetabula are farther apart, the angle
formed by the pubic arch is also greater in the female. All these bony characteristics facilitate childbearing and birth

Explanation:

When the foot is positioned for a lateral projection, the plantar surface should be perpendicular to the image receptor, so as to superimpose the metatarsals. This may be accomplished with the patient lying on either the affected or unaffected side (usually affected), that is, mediolateral or lateromedial. The talofibular articulation is best demonstrated in the medial oblique projection of the ankle 

Explanation:

Factors that regulate the number of x-ray photons produced at the target are used to control radiographic density, namely milliamperage and exposure time (mAs). Radiographic density is directly proportional to mAs (milliampere-seconds); if the mAs is cut in half, the radiographic density will decrease by one-half. Although kilovoltage is used primarily to regulate radiogaphic contrast, it may also be used to regulate radiographic density in variable kV (kilovolts) techniques, according to the 15% rule 

Explanation:

Perfect film–screen contact is essential to sharply recorded detail. Screen contact can be evaluated with a wire-mesh test. A spinning-top test is used to evaluate timer accuracy and rectifier operation. A penetrometer (aluminum step-wedge) is used to illustrate the effect of kV on contrast. A star pattern is used to measure resolving power of the imaging system

Explanation:

The mechanical device used to correct an ineffectual cardiac rhythm is a defibrillator. The two paddles attached to the unit are placed on a patient’s chest and used to introduce an  electric current in an effort to correct the dysrhythmia. A cardiac monitor is used to display, and sometimes record, electrocardiogram (ECG) readings and some pressure readings. The crash cart is a supply cart with various medications and equipment necessary for treating a
patient who is suffering from a myocardial infarction or other serious medical emergencies. It is periodically checked and restocked, usually by nursing, although radiographers may be responsible for a daily check of the plastic throwaway locks. These locks are used to ensure that the cart has not been tampered with or supplies inadvertently used in nonemergency situations. A resuscitation bag is used for ventilation, as during cardiopulmonary resuscitation

Explanation:

There are many terms (with which the radiographer must be familiar) that are used
to describe radiographic positioning techniques. Cephalad refers to that which is toward the head, and caudad to that which is toward the feet. Structures close to the source or beginning are said to be proximal, while those lying close to the midline are said to be medial

Explanation:

When barium fluorohalide absorbs x-ray energy, electrons are released and they divide into two groups. One electron group initiates immediate luminescence during the excited state of Eu2+. The other electron group becomes trapped within the phosphor’s halogen ions, forming a “color center.” These trapped phosphors are the phosphors that ultimately form the radiographic image because when exposed to a monochromatic laser light source these phosphors emit polychromatic light, termed photostimulated luminescence (PSL).
The PSP layer stores its latent image for several hours, however, after approximately 8 hours noticeable image fading will occur. The europium activator is important for the storage characteristic of the PSPs; it also has function similar to the sensitization specks within film emulsion—without europium, the image will not become manifest

Explanation:

Because the anode’s focal track is beveled (angled, facing the cathode), x-ray photons can freely diverge toward the cathode end of the x-ray tube. However, the “heel” of the focal
track prevents x-ray photons from diverging toward the anode end of the tube. This results in varying intensity from anode to cathode, fewer photons at the anode end, and more photons
at the cathode end. The anode heel effect is most noticeable using large image receptor sizes, short SIDs (source-to-image-receptor distances), and steep target angles

Explanation:

With the patient in the anteroposterior (AP) position, the scapula and upper thorax are normally superimposed. With the arm abducted, the elbow flexed, and hand supinated, much of the scapula is drawn away from the ribs. The patient should not be rotated toward the affected side, as this causes superimposition of ribs on the scapula. The exposure is made during quiet breathing to obliterate pulmonary vascular markings 

Explanation:

The type of shock associated with pooling of blood in the peripheral vessels is classified as neurogenic shock. This occurs in cases of trauma to the central nervous system
resulting in decreased arterial resistance and pooling of blood in peripheral vessels. Cardiogenic
shock is related to cardiac failure, as a result of interference with heart function. It can occur in cases of cardiac tamponade, pulmonary embolus, or myocardial infarction. Hypovolemic shock is related to loss of large amounts of blood, from either internal bleeding or hemorrhage
associated with trauma. Septic shock, as well as anaphylactic shock, is generally classified as vasogenic shock

Explanation:

An axial dorsoplantar projection is described; the central ray enters the dorsal surface of the foot and exits the plantar surface. The plantodorsal projection is done supine and requires cephalad angulation. The central ray enters the plantar surface and exits the dorsal surface

Explanation:

Surface landmarks, prominences, and depressions are very useful to the radiographer in locating anatomic structures not visible externally. The costal margin is at about the same
level as L3. The umbilicus is approximately at the same level as the L3–L4 interspace. The xiphoid tip is at about the same level as T10. The fourth lumbar vertebra is approximately atthe same level as the iliac crest

Explanation:

In the CR reader, a photomultiplier tube (PMT) or photodiode (PD) is used to detect PSL and convert it to electrical signals. The electrical energy is sent to an analog-to digital converter (ADC) where it becomes the digital image that is displayed, after a short delay, on a high-resolution monitor.In indirect capture DR, a flat-panel detector uses cesium iodide or gadolinium oxysulfide as the scintillator, i.e., that which captures x-ray photons and emits light. That light then transferred directly to the ADC via a photodetector coupling agent—a charge coupled device (CCD) or thin film transistor (TFT) 

Explanation:

Only two pieces of apparatus are needed to construct a characteristic curve . First, a penetrometer (aluminum step-wedge) is used to expose a film. Once the film is processed, a densitometer is needed to read the resulting densities. Log relative exposure is charted along the x (horizontal) axis; an increase in log relative exposure of 0.3 results from
doubling the exposure. Optical density is plotted on the y (vertical) axis and represents the amount of light transmitted through a film compared to the amount of light striking the film