Image acquisition and Evaluation Flashcards

Question

Conditions in which there is a lack of normal bone calcification include rickets. osteomalacia. osteoarthritis.

Answer 1

1 and 2 only EXPLANATION: Rickets and osteomalacia are disorders in which there is softening of bone. Rickets results from a deficiency of vitamin D and usually is found affecting the growing bones of young children. The body's weight on the soft bones of the legs results in bowed and misshapen legs. Osteomalacia is an adult condition in which new bone fails to calcify. It is a painful condition and can result in easily fractured bones, especially in the lower extremities. Osteoarthritis is seen often in the elderly and is characterized by degeneration of articular cartilage in adjacent bones. The resulting rubbing of bone against bone results in pain and deterioration. (Tortora and Derrickson, 11th ed., p. 190)

Answer 2

1.48 mR EXPLANATION: The relationship between x-ray intensity and distance from the source is expressed in the inverse-square law of radiation. The formula is i1/i2=D2sq/D2sq 10/x=36/16, 36x=160, x=4.44 EXPLANATION: Thus, x = 4.44 mR in 60 minutes and, therefore, 1.48 mR in 20 minutes. Distance has a profound effect on dose received and, therefore, is one of the cardinal rules of radiation protection. As distance from the source increases, dose received decreases. (Bushong, 8th ed., pp. 68–70)

Answer 3

20 mR EXPLANATION: If it is desired to determine entrance skin exposure (ESE), a small ionization chamber (pocket dosimeter) can be placed on the skin, and the approximate ESE can be read immediately. These devices are readily imaged, however, and are awkward to position. For these reasons, thermoluminescent dosimeters (TLDs) or optically stimulated luminescence (OSL) dosimeters are more easily used; they are precise and will not interfere with the radiographic image. The acceptable ESE for a PA chest is approximately 20 mR (12–26 mR is the acceptable range). An image taken with an ESE of 6 mR would be underexposed and require repeating. Similarly, ESEs of 38 mR and 0.6 R (600 mR) would lead to overexposed images that would need to be repeated. (Bushong, 8th ed., p. 586)

Answer 4

1, 2, and 3 EXPLANATION: The best way to ensure patient cooperation is through effective communication. A patient who understands what the examination entails, who knows what to expect, and what will be expected of him or her is better able to cooperate with the radiographer. This patient is more likely to be able to maintain the required position and suspend their respiration when required—thereby avoiding a repeated image. Radiographers who use their knowledge along with patience and critical thinking skills are more apt to obtain good images the first time around, thus avoiding repeat examinations. The use of AEC also helps avoid repeat radiographs; AEC will adjust the exposure—compensating for position, habitus, or pathology, and reducing the likelihood of repeat radiographs. (Dowd & Tilson, p 243)

Answer 5

decrease radiographic density and decrease the amount of scattered radiation generated within the part EXPLANATION: Limiting the size of the radiographic field (irradiated area) serves to limit the amount of scattered radiation produced within the anatomic part. As the amount of scattered radiation produced decreases, so does the resultant density within the radiographic image. Therefore, as field size decreases, scattered radiation production decreases, and overall density decreases. Limiting the size of the radiographic field is a very effective means of reducing the quantity of non–information-carrying scattered radiation (fog) produced, resulting in a shorter scale of contrast with fewer radiographic densities. Limiting the size of the radiographic field is also the most effective means of patient radiation protection. (Shephard, p. 203)

Answer 6

a vial. EXPLANATION: Injectable medications are available in two different kinds of containers. An ampule is a small container that usually holds a single dose of medication. A vial is a somewhat larger container that holds a number of doses of medication. The term bolus is used to describe an amount of fluid to be injected. A carafe is a narrow-mouthed container; it is not likely to be used for medical purposes. (Adler and Carlton, 4th ed., p. 309)

Answer 7

1 and 3 only EXPLANATION: Glucophage (metformin hydrochloride) is used as an adjunct to appropriate diet to lower blood glucose level in patients who have type 2 diabetes and whose hyperglycemia is not being managed satisfactorily with diet alone. Patients on metformin may have intravascular iodinated contrast studies if their renal function is within normal limits. Since the iodinated media, together with metformin, could induce renal failure or acute acidosis, the American College of Radiology currently recommends that patients on metformin have it withheld 48 hours after the exam. (Bontrager and Lampignano, 7th ed., p. 539)

Answer 8

350 mrad EXPLANATION: Patients occasionally will question the radiographer regarding the amount of radiation they are receiving during their examination. Most of these patients are merely curious because they have heard a recent news report about x-rays or have perhaps studied about x-rays in school recently. It is a good idea for radiographers to have some knowledge of average exposure doses for patients who desire this information. The curious patient also can be referred to the medical physicist for more detailed information. The average AP cervical spine radiograph delivers about 80 mrad (0.080 rad). The average AP supine lumbar spine radiograph delivers an ESE of about 350 mrad (0.35 rad). The average AP supine abdomen radiograph delivers about 300 mrad. (Dowd and Tilson, 2nd ed., p. 247)

Answer 9

crystalline material lacking typical crystalline structure. EXPLANATION: Flat-panel detectors used in DR are often made of an amorphous selenium (a-Se)–coated thin-film transistor (TFT) array. They function to convert the x-ray energy (emerging from the radiographed part) into an electrical signal. The TFT capacitors send the electrical signal to the analog-to-digital converter (ADC) to be changed to a digital signal. Amorphous selenium refers to a crystalline material (selenium) that lacks its crystalline structure. Amorphous selenium or silicon is used to produce the direct-conversion flat-panel detectors used in DR. (Bushong, 8th ed., p. 404)

Answer 10

less density more contrast EXPLANATION: Less scattered radiation is generated within a part as the kilovoltage is decreased, as the size of the field is decreased, and as the thickness and density of tissue decrease. As the quantity of scattered radiation decreases from any of these sources, the less is the total density of the resulting image. (Carlton and Adler, 4th ed., p. 256)

Answer 11

The mAs remains unchanged as film–screen speed decreases. EXPLANATION: As the speed of the film–screen system decreases, an increase in milliampere-seconds usually is required to maintain radiographic density. However, when an AEC (phototimer or ionization chamber) is used, the system is programmed for the use of a particular film–screen speed. If a slower speed screen cassette/IR is placed in the Bucky tray, the AEC has no way of recognizing it as different and will result in the exposure required for the system for which it is programmed. For example, if the system were programmed for a 400-speed film–screen combination, and if a 200-speed screen cassette/IR were placed in the Bucky tray, the AEC would produce an exposure appropriate for the 400 speed system, and the resulting image would have half the required radiographic density. (Shephard, p. 291)

Answer 12

pelvis EXPLANATION: The pelvic girdle consists of two innominate (hip, or coxal) bones, one on each side of the sacrum. Each innominate bone consists of three fused bones—the ilium, ischium, and pubis. Parts of these three bones contribute to formation of the acetabulum—the socket articulation for the femoral head. The ilia are the large, superior bones whose medial auricular surface forms the sacroiliac joints bilaterally. The broad, flat portion of each ilium is the ala, or wing; the upper part of the ala forms a ridge of bone called the iliac crest, which terminates in anterior and posterior iliac spines. (Bontrager and Lampignano, 6th ed., p 263)

Answer 13

shoulder girdle elevation & increased AP diameter of the chest EXPLANATION: Emphysema is a chronic obstructive pulmonary disease (COPD) characterized by pathologic distension of the pulmonary alveoli with (destructive) changes in their walls, resulting in a loss of elasticity. Emphysema is seen occasionally following asthma or tuberculosis, but it is caused most frequently by cigarette smoking. Because the emphysematous patient's greatest difficulty is exhalation, it becomes a conscious, forced effort. Breathing is shallow and rapid. Forced and ineffective breathing results in expansion of the AP diameter of the chest and elevated shoulder girdle in established emphysema. Hyperventilation results from too frequent deep breaths in the anxious or tense individual. This results in a feeling of dizziness and tingling of the extremities. (Tortora and Derrickson, 11th ed., p. 887)

Answer 14

high-speed rotation, short pulsed exposures, withstanding millions of heat units. EXPLANATION: A CT imaging system has three component parts—a gantry, a computer, and an operating console. The gantry component includes an x-ray tube, a detector array, a high-voltage generator, a collimator assembly, and a patient couch with its motorized mechanism. Although the CT x-ray tube is similar to direct-projection x-ray tubes, it has several special requirements. The CT x-ray tube must have a very high short-exposure rating and must be capable of tolerating several million heat units while still having a small focal spot for optimal resolution. To help tolerate the very high production of heat units, the anode must be capable of high-speed rotation. The x-ray tube produces a pulsed x-ray beam (1–5 ms) using up to about 1,000 mA. (Bushong, 8th ed., pp. 429–430; Bontrager and Lampignano, 6th ed., p. 731)

Answer 15

1 and 2 only EXPLANATION: The American Hospital Association identifies 12 important areas in its "Patients' Bill of Rights." These include the right to refuse treatment (to the extent allowed by law), the right to confidentiality of records and communication, and the right to continuing care. Other patient rights identified are the right to informed consent, privacy, respectful care, access to records, refuse to participate in research projects, and an explanation of the hospital bill. (Torres et al, p 12)

Answer 16

assault. EXPLANATION: Assault is the threat of touching or laying hands on someone. If a patient feels threatened by a practitioner, either because of the tone or pitch of the practitioner's voice or because the practitioner uses words that are threatening, the practitioner can be accused of assault. A radiographer who performs the wrong examination on a patient may be charged with battery. Battery refers to the unlawful laying of hands on a patient. The radiographer also could be charged with battery if a patient were moved about roughly or touched in a manner that is inappropriate or without the patient's consent. False imprisonment may be considered if a patient is ignored after stating that he or she no longer wishes to continue with the procedure or if restraining devices are used improperly or used without a physician's order. The accusation of defamation can be upheld when patient confidentiality is not respected, and as a result, the patient suffers embarrassment or mockery. (Adler and Carlton, 4th ed., p. 374)

Answer 17

1 and 2 only EXPLANATION: The AP axial projection (Towne method) of the skull requires that the CR be angled 30 degrees caudad if the OML is perpendicular to the IR (37 degrees caudad if the IOML is perpendicular to the IR). The frontal and facial bones are projected down and away from superimposition on the occipital bone. If positioning is accurate, the dorsum sella and posterior clinoid processes will be demonstrated within the foramen magnum. If the CR is angled excessively, the posterior aspect of the arch of C1 will appear in the foramen magnum. (Frank, Long, and Smith, 11th ed., vol. 2, p. 316)

Answer 18

a foreign body, soft tissue EXPLANATION: The lateral hand in extension, with appropriate technique adjustment, is recommended to evaluate foreign-body location in soft tissue. A small lead marker frequently is taped to the spot thought to be the point of entry. The physician then uses this external marker and the radiograph to determine the exact foreign-body location. Extension of the hand in the presence of a fracture would cause additional and unnecessary pain and possibly additional injury. (Frank, Long, and Smith, 11th ed., vol. 1, p. 121)

Answer 19

2.2 mR/min EXPLANATION: The relationship between x-ray intensity and distance from the source is expressed in the inverse square law of radiation. The formula is Substituting known values,: Note the inverse relationship between distance and dose. As distance from the source of radiation increases, dose rate decreases significantly. (Bushong, p 67)

Answer 20

stimulate defecation. EXPLANATION: Cathartics stimulate defecation and are used in preparation for radiologic examinations of the large bowel. Diuretics are used to promote urine elimination in individuals whose tissues are retaining excessive fluid. Emetics induce vomiting, and antitussives are used to inhibit coughing. (Torres et al., 6th ed., p. 283)

Answer 21

Intervertebral spaces Intervertebral foramina EXPLANATION: The thoracic intervertebral (disk) spaces are demonstrated in the AP and lateral projections, although they are probably best demonstrated in the lateral projection. The thoracic apophyseal joints are 70 degrees to the MSP and are demonstrated in a steep (70-degree) oblique position. The thoracic intervertebral foramina, formed by the vertebral notches of the pedicles, are 90 degrees to the MSP. They are, therefore, well demonstrated in the lateral position. (Bontrager and Lampignano, 6th ed., p. 316)

Answer 22

fog. EXPLANATION: This is the definition of fog. Anything other than intensifying screen light or primary x-radiation is undesirable in terms of image exposure. Log-relative exposure is the amount of exposure required to produce a given density as measured on the sensitometric graph. Optical density is normal radiographic density. An artifact is anything foreign to the image; the term could include fog, but it also covers many physical interferences. (Selman, 9th ed., pp. 196–197)

Answer 23

patient skin dose EXPLANATION: It is our ethical responsibility to minimize the radiation dose to our patients. X-rays produced at the tungsten target make up a heterogeneous primary beam. There are many "soft" (low-energy) photons that, if not removed by filters, would only contribute to greater patient skin dose. They are too weak to penetrate the patient and contribute to the image-forming radiation; they penetrate a small thickness of tissue and are absorbed. (Bushong, 8th ed., p. 11)

Answer 24

the incident electron is deflected, with resulting energy loss EXPLANATION: Bremsstrahlung (or Brems) radiation is one of the two kinds of x-rays produced at the tungsten target of the x-ray tube during interaction between high-speed electrons coming from the filament and the anodes' tungsten atoms. The incident high-speed electron, passing through a tungsten atom, is attracted by the positively charged nucleus and, therefore, is deflected from its course, with a resulting loss of energy. This energy is given up in the form of an x-ray photon. (Bushong, 8th ed., pp. 151–152)

Answer 25

radiography of pediatric patients with a myelomeningocele defect should be performed in the supine position. EXPLANATION: Radiography of pediatric patients with a myelomeningocele defect should be performed in the prone position rather than in the routine supine position. The supine position would put unnecessary pressure on the protrusion of the meninges and spinal cord. All the other statements in the question are true. The anatomic dimensions of children are different from those of adults, and this must be kept in mind when performing pediatric radiography. The liver occupies a larger area of the abdominal cavity in a child than in an adult. This causes the kidneys to be in a lower position. Generally, the kidneys will be midway between the diaphragm and the symphysis pubis. Chest radiography for the pediatric patient varies depending on the age of the child. Neonates are routinely radiographed in the supine position. Although infants also may be examined in the supine position, it is preferable to examine them by placing the infant securely in a support device to obtain a good PA erect radiograph. Exceptions to this rule are made if the infant is in respiratory distress. To avoid aggravating the respiratory distress, an erect AP radiograph usually is obtained. (Dowd and Tilson, 2nd ed., vol. 2, pp. 1004–1005, 1013)

Answer 26

cathartics and cleansing enemas. EXPLANATION: Diagnostic x-ray examinations that require contrast agents include upper GI series, lower GI series (BE), IVU, and the occasional GB series. Patient preparation is somewhat different for each of these examinations. An iodinated contrast agent, usually in the form of several pills, is taken by the patient the evening before a scheduled GB examination, and only water is allowed the morning of the examination. The patient scheduled for an upper GI series must receive NPO (nothing by mouth) after midnight. A lower GI series (BE) requires that the large bowel be very clean prior to the administration of barium; this requires the administration of cathartics (laxatives) and cleansing enemas. Preparation for an IVU requires that the patient be NPO after midnight; some institutions also require that the large bowel be cleansed of gas and fecal material. Aftercare for barium examinations is very important. Patients typically are instructed to take milk of magnesia, increase their intake of fiber, drink plenty of water, and expect changes in stool color until all barium is evacuated and to call their physician if they do not have a bowel movement within 24 hours. Because water is removed from the barium sulfate suspension in the large bowel, it is essential to make patients understand the importance of these instructions to avoid barium impaction in the large bowel. The use of barium sulfate suspensions is contraindicated when ruling out visceral perforation. (Bontrager and Lampignano, 6th ed., p. 501)

Answer 27

1, 2, and 3 EXPLANATION: The greater and lesser tubercles are prominences on the proximal humerus separated by the intertubercular (bicipital) groove. The AP projection of the humerus/shoulder places the epicondyles parallel to the IR 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 IR and demonstrates the lesser tubercle in profile. (Ballinger & Frank, vol 1, pp 161–162)

Answer 28

Varices Achalasia EXPLANATION: Dilated, twisted veins, or varices, of the esophagus are frequently associated with obstructive liver disease or cirrhosis of the liver. These esophageal veins enlarge and can rupture, causing serious hemorrhage. Achalasia is dilation of the esophagus as a result of the cardiac sphincter's failure to relax and allow food to pass into the stomach. Dysphasia is a speech impairment resulting from a brain lesion; it is unrelated to the esophagus. Dysphagia refers to difficulty swallowing and is the most common esophageal complaint. Hiatal hernia is another common esophageal problem; it is characterized by protrusion of a portion of the stomach through the cardiac sphincter. It is a common condition, and many individuals with the condition are asymptomatic. Each of these conditions of the esophagus may be evaluated with an esophagogram. Positions usually include the posteroanterior, right anterior oblique, and right lateral positions. (Bontrager and Lampignano, 6th ed., pp. 463–464)

Answer 29

Hysterosalpingography EXPLANATION: The lithotomy position is generally employed for hysterosalpingography. The lithotomy position requires that the patient lie on the back with buttocks at the edge of the table. The hips are flexed, the knees are flexed and resting on leg supports, and the feet rest in stirrups. (Adler & Carlton, p 202)

Answer 30

protected from injury. EXPLANATION: When a patient is experiencing a seizure, he or she should be protected from striking any hard surfaces or falling. The patient exhibits uncontrollable body movements. Any attempt to place the patient in a semierect position or to administer a sedative would prove futile. Following the seizure, it is important to place the patient on his or her side to prevent aspiration of any vomitus or oral secretions. (Adler & Carlton, p 248)

Answer 31

muscle mass. bone calcium. EXPLANATION: Gerontology, or geriatrics, is the study of the elderly. Although bone demineralization and loss of muscle mass occur to a greater or lesser degree in most elderly individuals, the radiographer must not assume that all gerontologic patients are hard of hearing, clumsy, or not mentally alert. Today, many elderly people remain very active, staying mentally and physically agile well into their so-called golden years. The radiographer must keep this in mind as he or she provides age-specific care to the gerontologic patient. (Torres et al., 6th ed., p. 211)

Answer 32

Patellofemoral articulation Tangential patella EXPLANATION: Note the relationship between the thigh, lower leg, patella, and CR. The CR is directed parallel to the plane of the patella, thereby providing a tangential projection of the patella (i.e., patella in profile) and an unobstructed view of the patellofemoral articulation (Figure 2–42). A tunnel view is required to demonstrate the intercondyloid fossa and the articulating surfaces of the tibia and femur. (Frank, Long, and Smith, 11th ed., vol. 1, p. 325)

Answer 33

rubella. mumps. influenza. EXPLANATION: 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 health care practitioners must wear a regular (string) mask to enter a droplet precautions isolation room. (Adler and Carlton, 4th ed., p. 233)

Answer 34

15 to 30 degrees caudad EXPLANATION: When the clavicle is examined in the PA axial projection, the CR must be directed 15 to 30 degrees caudad to project most of the clavicle's length above the ribs. The direction of the CR is reversed when examining the patient in the AP position. (Frank, Long, and Smith, 11th ed., Vol. I, p. 210)

Answer 35

1. partial or complete collapse of pulmonary lobe(s) 2. air in the pleural cavity 3. foreign body EXPLANATION: The phase of respiration is exceedingly important in thoracic radiography because lung expansion and the position of the diaphragm strongly influence the appearance of the finished radiograph. Inspiration and expiration radiographs of the chest are taken to demonstrate air in the pleural cavity (pneumothorax), to demonstrate atelectasis (partial or complete collapse of one or more pulmonary lobes) or the degree of diaphragm excursion, or to detect the presence of a foreign body. The expiration image will require a somewhat greater exposure (6–8 kV more) to compensate for the diminished quantity of air in the lungs. (Frank, Long, and Smith, 11th ed., vol. 1, p. 520)

Answer 36

ventricular septal defect. EXPLANATION: Ventricular septal defect is a congenital heart condition characterized by a hole in the interventricular septum that allows oxygenated and unoxygenated blood to mix. Some interventricular septal defects are small and close spontaneously; others require surgery. Coarctation of the aorta is a narrowing or constriction of the aorta. Atrial septal defect is a small hole (the remnant of the fetal foramen ovale) in the interatrial septum. It usually closes spontaneously in the first months of life; if it persists or is unusually large, surgical repair is necessary. The ductus arteriosus is a short fetal blood vessel connecting the aorta and pulmonary artery that usually closes within 10 to 15 hours after birth. A patent ductus arteriosus is one that persists and requires surgical closure. (Taber, 20th ed., p. 2,323)

Answer 37

0.05 second EXPLANATION: When a spinning top is used to test the timer efficiency of full-wave-rectified single-phase equipment, the result is a series of dots or dashes, with each dot representing a pulse of radiation. With full-wave-rectified current and a possible 120 dots (pulses) available per second, one should visualize 12 dots at 1/10 second, 6 dots at 0.05 second, 10 dots at 1/12 second, and 3 dots at 0.025 second. Because three-phase equipment is at almost constant potential, a synchronous spinning top must be used for timer testing, and the result is a solid arc (rather than dots). The number of degrees covered by the arc is measured and equated to a particular exposure time. (Selman, 9th ed., p. 106)

Answer 38

2 and 3 only EXPLANATION: After forceful eversion or inversion injuries of the ankle, AP stress studies are valuable to confirm the presence of a ligament tear. Keeping the ankle in an AP position, the physician guides the ankle into inversion and eversion maneuvers. Characteristic changes in the relationship of the talus, tibia, and fibula will indicate ligament injury. Inversion stress demonstrates the lateral ligament, whereas eversion stress demonstrates the medial ligament. A fractured ankle would not be manipulated in this manner. (Frank, Long, and Smith, 11th ed., vol. 1, p. 293)

Answer 39

10 to 15 degrees caudal EXPLANATION: With a patient in the PA position and the OML perpendicular to the table, a 15- to 20-degree caudal angulation would place the petrous ridges in the lower third of the orbit. To achieve the same result in a baby or a small child, it is necessary for the radiographer to decrease the angulation or modify the angulation to 10 to 15 degrees caudal. The reason for this can be understood by examining the baselines for skull positioning. In the adult skull, the OML and IOML are about 7 degrees apart. In a baby or small child, the difference is larger, about 15 degrees apart. Remember that in adults, the head makes up about one-seventh the length of the body. In children, the head is about one-fourth the length of the body. These differences must be considered in radiographic examination of the skull for babies. (Frank, Long, and Smith, 11th ed., vol. 3, p. 193)

Answer 40

1. Name of facility where exam performed 2. Examination date EXPLANATION: X-ray images are often subpoenaed as court evidence in cases of medical litigation. In order to be considered as legitimate legal evidence, each x-ray image must contain certain essential and specific patient information. Essential information that must be included on each image is patient identification, the identity of the facility where the x-ray study was performed, the date that the study was performed, and a right- or left-side marker. Other useful information that may be included, but that is not considered essential, is additional patient demographics such as their date of birth, the identity of the referring physician, the time of day that the study was performed, and the identity/initials of the radiographer performing the examination.

Answer 41

Orthopnea EXPLANATION: A patient with orthopnea is unable to breathe while lying down. When the body is recumbent, the diaphragm and abdominal viscera move to a more superior position. It is therefore more difficult to breathe deeply. Patients with orthopnea must be examined in an erect or semierect position. Dyspnea refers to difficulty breathing in any body position. Apnea describes cessation of breathing for short intervals. Oligopnea is infrequent breathing—as slow as 6 to 10 respirations per minute. (Ehrlich, McCloskey, & Daly, p 127)

Answer 42

Genetically significant dose EXPLANATION: The genetically significant dose (GSD) illustrates that large exposures to a few people are cause for little concern when diluted by the total population. On the other hand, we all share the burden of the radiation that is received by the total population, and especially as the use of medical radiation increases, each individual's share of the total exposure increases. (Bushong, 8th ed., p. 589)

Answer 43

respiratory pathway obstruction above the larynx EXPLANATION: The respiratory passageways include the nose, pharynx, larynx (upper respiratory structures), trachea, bronchi, and lungs (lower structures). If obstruction of the breathing passageways occurs in the upper respiratory tract, above the larynx (i.e., in the nose or pharynx), tracheotomy may be performed to restore breathing. Intubation can be done into the lower structures, larynx, and trachea, moving aside any soft obstruction and restoring the breathing passageway. (Tortora and Derrickson, 11th ed., p. 856)

Answer 44

Apply pressure, cold compress, then apply warm, moist heat.

Answer 45

1, 2, and 3 EXPLANATION: Intensifying-screen phosphors that have a high atomic number are more likely to absorb a high percentage of the incident x-ray photons and convert x-ray photon energy to fluorescent light energy. How efficiently the phosphors detect and interact with the x-ray photons is termed quantum detection efficiency. How effectively the phosphors make this energy conversion is termed conversion efficiency. (Shephard, p. 65)

Answer 46

urinary tract. EXPLANATION: Hospital-acquired infections (HAIs) are also referred to as nosocomial. Despite the efforts of infectious disease departments, HAIs continue to be a problem in hospitals today. This is at least partly due to there being a greater number of older, more vulnerable patients and an increase in the number of invasive procedures performed today (i.e., needles and catheters). The most frequent site of HAI is the urinary tract, followed by wounds, the respiratory tract, and blood. (Torres et al., 6th ed., p. 47)

Answer 47

2 and 3 only EXPLANATION: If a fairly large patient is turned prone, the abdominal measurement will be significantly different from the AP measurement as a result of the effect of compression. Thus, the part is essentially "thinner," and less scattered radiation will be produced. If the patient remains supine and a compression band is applied, a similar effect will be produced. Beam restriction is probably the single most effective means of reducing the production of scattered radiation. Grid ratio affects the cleanup of scattered radiation; it has no effect on the production of scattered radiation. (Shephard, p. 203)

Answer 48

Cross-table lateral hip EXPLANATION: The cross-table lateral hip will bring the primary beam in closest proximity to the male reproductive organs. A grid is required, and gonadal shielding is most likely not possible. Close, accurate collimation is recommended to keep exposure to a minimum, but the cross-table lateral hip will deliver the greatest dose to the male reproductive organs. (Bontrager, p 267)

Answer 49

the photoelectric effect EXPLANATION: In the photoelectric effect, the incident (low-energy) photon is completely absorbed and thus is responsible for producing contrast and contributing to patient dose. The photoelectric effect is the interaction between x-ray and tissue that predominates in the diagnostic range. In Compton scatter, only partial absorption occurs, and most energy emerges as scattered photons. In coherent scatter, no energy is absorbed by the part; it all emerges as scattered photons. Pair production occurs only at very high energy levels, at least 1.02 MeV. (Bushong, 8th ed., p. 176)

Answer 50

Reduced patient dosage EXPLANATION: When using photospot camera film, there is reduced patient dosage (A). In fact, dosage is at least half of that which occurs with cassette-loaded spot film (A). A smaller anatomical image size (B) is produced with photospot camera film, when compared to cassette-loaded spot film. The photospot camera provides adequate image quality without interruption of the fluoroscopic examination and an increased rate of exposures (C) of up to 12 images per second. With cassette-loaded spot films, the fluoroscopic examination must be interrupted while the film moves into position within a lead-lined compartment, the mA is switched from low to high mA, and the rotor speed is increased, which can delay the exposure for a couple of seconds. Both photospot camera film and cassette-loaded spot film must be chemically processed (D) in a darkroom. (Bushong, 10th ed., p. 413).

Answer 51

15 EXPLANATION: To change nongrid to grid exposure or to adjust exposure when changing from one grid ratio to another, it is necessary to recall the factor for each grid ratio: no grid = 1x Orig. mAs 5: 1 grid = 2x Orig. mAs 6: 1 grid = 3x Orig. mAs 8: 1 grid = 4x Orig. mAs 10: 1 grid =5x Orig. mAs 12: 1 grid = 5x Orig. mAs 16: 1 grid = 6x Orig. mAs EXPLANATION: Therefore, to change from nongrid to a 12:1 grid, multiply the original milliampere-seconds value by a factor of 5. A new milliampere-seconds value of 15 is required. (Shephard, pp. 247–248)

Answer 52

1, 2, and 3 EXPLANATION: Occupationally exposed individuals are concerned principally with late (i.e., long-term or delayed) effects of ionizing radiation such as radiation-induced genetic effects, leukemia, and cancers (e.g., bone, lung, thyroid, and breast), as well as local effects, such as skin erythema, infertility, and cataracts—these can occur many years following initial exposure to low levels of ionizing radiation. The long-term/delayed effects usually are chronic, and many are represented by the linear, nonthreshold dose–response curve. (Bushong, 10th ed., pp. 507 and 519)

Answer 53

1 and 2 only EXPLANATION: In the lateral position of the skull, the midsagittal plane must be parallel to the IR and the interpupillary line vertical. Flexion of the head is adjusted until the IOML is parallel to the IR. The CR should enter about 2 inches superior to the EAM. The centering point for a lateral sella turcica is ¾ inch anterior and superior to the EAM. (Frank, Long, and Smith, 11th ed., vol. 2, p. 306)

Answer 54

beam HVL EXPLANATION: Aluminum filters are used to decrease patient skin dose by absorbing the low-energy photons (therefore, decreased milliroentgen output) that do not contribute to the image but do contribute to patient skin dose. HVL is defined as that thickness of any absorber that will decrease the intensity of a particular beam to one-half its original value. As filtration of an x-ray beam is increased, the overall average energy of the resulting beam is greater (because the low-energy photons have been removed)—and, therefore, the HVL thickness required would be greater. (Bushong, 8th ed., p. 165)

Answer 55

medical asepsis. EXPLANATION: Medical asepsis refers to practices that reduce the spread of microbes, and therefore the chance of spreading disease or infection. Washing your hands is an example of medical asepsis. It reduces the spread of infection, but it does not eliminate all microorganisms. Disinfection involves the use of chemicals to either inactivate or inhibit the growth of microbes. The complete killing of all microorganisms is termed sterilization. Surgical asepsis refers to the technique used when performing procedures to prevent contamination. (Adler & Carlton, p 211)

Answer 56

Changing from an 8:1 grid technique to nongrid EXPLANATION: Converting from an 8:1 grid to nongrid requires about a fourfold decrease in milliampere-seconds. Increasing the kilovoltage by 15% and cutting the milliampere-seconds in half would reduce patient dose by half. Changing from a 200-speed system to a 400-speed system also would require the milliampere-seconds to be halved. Therefore, the largest decrease will occur with removal of a grid. (Bushong, 8th ed., p. 252)

Answer 57

Lidocaine EXPLANATION: Lidocaine (Xylocaine) is an antiarrhythmic used to prevent or treat cardiac arrhythmias (dysrhythmia). Epinephrine (Adrenalin) is a bronchodilator. Bronchodilators may be administered in a spray mister, such as for asthma, or by injection to relieve severe bronchospasm. Nitroglycerin and verapamil are vasodilators. Vasodilators permit increased blood flow by relaxing the walls of the blood vessels. (Adler and Carlton, 4th ed., p. 304)

Answer 58

45 degrees oblique, affected side down. EXPLANATION: When viewing the glenoid fossa from the anterior, it is seen to angle posteriorly and laterally approximately 45 degrees. To view it in profile, then, it must be placed so that its surface is perpendicular to the IR. The patient is positioned in a 45-degree oblique, affected-side-down position, which places the glenoid fossa approximately perpendicular to the IR. The arm is abducted slightly, the elbow is flexed, and the hand and forearm are placed over the abdomen. The CR is directed perpendicular to the glenohumeral joint. (Frank, Long, and Smith, 11th ed., vol. 1, pp. 192–193)

Answer 59

the arm should be in internal rotation. EXPLANATION: The inferosuperior axial (nontrauma, Lawrence method) projection of the shoulder demonstrates the glenohumeral joint and adjacent structures. The patient is supine with arm abducted 90°, and in external rotation. The (horizontal) CR is directed medially 25° to 30° through the axilla. The coracoid process and lesser tubercle are seen in profile. (Bontrager, p 179)

Answer 60

9 ``` EXPLANATION: To change nongrid exposures to grid exposures, or to adjust exposure when changing from one grid ratio to another, you must remember the factor for each grid ratio: No grid = 1 x the original mAs 5:1 grid = 2 x the original mAs 6:1 grid = 3 x the original mAs 8:1 grid = 4 x the original mAs 12:1 grid = 5 x the original mAs 16:1 grid = 6 x the original mAs To adjust exposure factors, you simply compare the old with the new: x = 9 mAs using 16:1 grid. (Shepard, pp. 247–248) ```

Answer 61

(A) Pylorus (B) Duodenum (C) Ileum (D) Sigmoid ``` EXPLANATION: (A) Pylorus (B) Duodenum (C) Ileum (D) Sigmoid With oral administration, barium sulfate suspension would first pass through the upper gastrointestinal (GI) tract—mouth, pharynx, esophagus, stomach (fundus, body, pylorus), small bowel (duodenum, jejunum, ileum), large bowel (cecum, ascending colon, right colic/hepatic flexure), transverse colon, left colic/splenic flexure, and descending colon, sigmoid colon, rectum). (Tortora and Derrickson, 11th ed., pp. 911–932) ```

Answer 62

a line between the maxillary occlusal plane and the mastoid tip is vertical. EXPLANATION: To clearly demonstrate the atlas and axis without superimposition of the teeth or the base of the skull, a line between the maxillary occlusal plane (edge of upper teeth) and mastoid tip must be vertical. If the head is flexed too much, the teeth will be superimposed. If the head is extended too much, the cranial base will be superimposed on the area of interest. A line between the mentum and the mastoid tip is used to demonstrate the odontoid process only through the foramen magnum (Fuchs method). (Frank, Long, and Smith, 11th ed., vol. 1, p. 393)

Answer 63

Trochlea EXPLANATION: The distal humerus articulates with the proximal radius and ulna to form the elbow joint. Specifically, the semilunar/trochlear notch of the proximal ulna articulates with the trochlea of the distal medial humerus. The capitulum is lateral to the trochlea and articulates with the radial head (Figure 2–50). (Frank, Long, and Smith, 11th ed., vol. 1, p. 99)

Answer 64

1 and 2 only EXPLANATION: The image intensifier can be coupled to the TV camera via a fiber-optic bundle or via a lens coupling device. The fiber-optic connection offers less fragility, more compactness, and ease of maneuverability. The big advantage of the objective lens is that it allows the use of auxiliary imaging devices such as a cine camera or spot-film camera.(Bushong, 8th ed., p. 366)

Answer 65

1 and 2 only EXPLANATION: A patient who is having a BE generally is required to have a low-residue diet for 1 or 2 days, followed by cathartics and cleansing enemas prior to the examination. Any retained fecal material can simulate or obscure pathology. A patient who is scheduled for a pyelogram must have the preceding meal withheld to avoid the possibility of aspirating vomitus in case of an allergic reaction. A metastatic survey does not require the use of contrast media, and no patient preparation is necessary. (Torres et al., 6th ed., p. 234)

Answer 66

paralytic ileus. EXPLANATION: Volvulus and intussusception both involve a mechanical "closure" or obstruction of the intestinal lumen by a change in the continuous pathway of the GI tract—volvulus by a twisting of the bowel on itself causing obstruction and intussusception by "telescoping" of the bowel causing obstruction. Meconium ileus is another form of mechanical obstruction where meconium (first feces of a newborn) becomes hardened and impacted, causing obstruction. Paralytic (or adynamic) ileus, however, is an obstruction caused by loss of peristaltic movement of the intestine. (Bontrager and Lampignano, 6th ed., p. 660)

Answer 67

18 to 20 inches above the level of the vein. EXPLANATION: It is generally recommended that the IV bottle/bag be kept 18 to 20 inches above the level of the vein. If the container is too high, the pressure of the IV fluid can cause it to pass through the vein into surrounding tissues, causing a painful and potentially harmful condition. If the IV container is too low, blood may return through the needle into the tubing, form a clot, and obstruct the flow of IV fluid. (Torres et al., 6th ed., p. 323)

Answer 68

1 and 2 only 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 fog, thus decreasing radiographic contrast. (Selman, 9th ed., p. 117)

Answer 69

1 only EXPLANATION: When performing bedside radiography in a contact isolation room, the radiographer should wear a gown and gloves. The cassettes are prepared for the examination by placing a pillowcase over them to protect them from contamination. Whenever possible, one person should manipulate the mobile unit and remain "clean," whereas the other handles the patient. The mobile unit should be cleaned with a disinfectant on exiting the patient's room, not prior to entering. (Torres et al., 6th ed., p. 69)

Answer 70

5 mSv EXPLANATION: According to the NCRP, the annual occupational whole-body dose equivalent limit is 50 mSv (5 rem or 5000 mrem). The total gestational dose equivalent limit for embryo/fetus of a pregnant radiographer is 5 mSv (500 mrem or 0.5 rem); the monthly dose equivalent limit is 0.5 mSv (50 mrem or 0.05rem). The annual occupational whole-body dose equivalent limit for students under the age of 18 years is 1 mSv (100 mrem or 0.1 rem). The annual occupational dose equivalent limit for the lens of the eye, a particularly radiosensitive organ, is 150 mSv (15,000 mrem or 15 rem). The annual occupational dose equivalent limit for the skin and extremities is 500 mSv (50,000 mrem or 50 rem). (Bushong, 9th ed, p 619)

Answer 71

whole-body dose EXPLANATION: Every radiographic examination involves an ESE, which can be determined fairly easily. It also involves a gonadal dose and a marrow dose, which, if needed, can be calculated by the radiation physicist. If the ESE of a particular examination were calculated to determine the equivalent whole-body dose, this would be termed the effective dose. For example, the ESE of a PA chest radiograph is approximately 70 mrem, whereas the effective dose is 10 mrem. The effective (whole body) dose is much less because much of the body is not included in the primary beam. (Fosbinder and Kelsey, p. 390)

Answer 72

300 mrad EXPLANATION: Patients occasionally will question the radiographer regarding the amount of radiation they are receiving during their examination. Most of these patients are merely curious because they have heard a recent news report about x-rays or have perhaps studied about x-rays in school recently. It is a good idea for radiographers to have some knowledge of average exposure doses for patients who desire this information. The curious patient also can be referred to the medical physicist for more detailed information. The average anteroposterior (AP) supine lumbar spine radiograph delivers an ESE of about 350 mrad (0.35 rad). The average AP supine abdomen radiograph delivers about 300 mrad; the average AP cervical spine radiograph delivers about 80 mrad. (Dowd and Tilson, 2nd ed., p. 247)

Answer 73

1, 2, and 3 EXPLANATION: The x-ray tube anode is designed according to the line-focus principle, that is, with the focal track beveled (Figure 6–24). This allows a larger actual focal spot to project a smaller effective focal spot, resulting in improved recorded detail with less blur. However, because of the target angle, penumbral blur varies along the longitudinal tube axis, being greater at the cathode end of the image and less at the anode end of the image. Therefore, better detail will be appreciated using small focal spots at the anode end of the x-ray beam and at longer SIDs. (Bushong, 8th ed., p. 287)

Answer 74

7 mR EXPLANATION: The intensity/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 it is expressed in the following equation: EXPLANATION: Substituting known values: EXPLANATION: Thus, x = 14.4 mR/h and, therefore, 7.2 mR in 30 minutes. (Bushong, 8th ed., pp. 68–70)

Answer 75

1 and 2 only EXPLANATION: Irradiation during pregnancy, especially in early pregnancy, must be avoided. The fetus is particularly radiosensitive during the first trimester, during much of which time pregnancy may not even be suspected. High-risk examinations include pelvis, hip, femur, lumbar spine, cystograms and urograms, and upper and lower gastrointestinal (GI) series. During the first trimester, specifically the 2nd to 10th weeks of pregnancy (i.e., during major organogenesis), if the radiation dose is sufficient, fetal anomalies can be produced. Skeletal and/or organ anomalies can appear if irradiation occurs in the early part of this time period, and neurologic anomalies can be formed in the latter part; mental retardation and childhood malignant diseases, such as cancers or leukemia, and retarded growth/development also can result from irradiation during the first trimester. Fetal irradiation during the second and third trimesters is not likely to produce anomalies but rather, with sufficient dose, some type of childhood malignant disease. Fetal irradiation during the first 2 weeks of gestation can result in embryonic resorption or spontaneous abortion. It must be emphasized, however, that the likelihood of producing fetal anomalies at doses below 20 rad is exceedingly small and that most general diagnostic examinations are likely to deliver fetal doses of less than 1 to 2 rad. (Bushong, 8th ed., pp. 544–546)

Answer 76

Hill-Sachs defect. EXPLANATION: A Hill-Sachs defect is a compression fracture of the posterolateral humeral head, usually associated with anterior dislocation of the shoulder joint. It can involve the cartilage of the humeral head, causing instability and predisposing the shoulder to subsequent dislocations. A Bankart lesion is a fracture of the anteroinferior portion of the rim of the glenoid fossa. A rotator cuff tear involves injury to one or more of the muscles participating in formation of that muscular structure. The supraspinatus, infraspinatus, subscapularis, and teres minor are the major muscles of the rotator cuff. Adhesive capsulitis, or "frozen shoulder," causes very diminished shoulder movement as a result of chronic joint inflammation. (Bontrager and Lampignano, 6th ed., p 189)

Answer 77

37 ms EXPLANATION: The milliampere-seconds (mAs) formula is milliamperage x time = mAs. With two of the factors known, the third can be determined. To find the milliampere-seconds value that was used originally, substitute the known values: EXPLANATION: We have increased the kilovoltage to 86 kV, an increase of 15%, which has an effect similar to that of doubling the milliampere-seconds. Therefore, only 15 mAs is now required as a result of the kilovoltage increase: EXPLANATION: Thus, x = 0.0375-s exposure = 37.5 ms. (Selman, 9th ed., p. 214)

Answer 78

Tangential metatarsals/toes EXPLANATION: The tangential projection projects the sesamoid bones separate from adjacent structures. The patient is best examined in the prone position because this places the parts of interest closest to the IR. The affected foot is dorsiflexed so as to place its plantar surface 15 to 20 degrees with the vertical. The CR is directed perpendicular to the posterior surface of the foot (near the metatarsophalangeal joints). The dorsoplantar and oblique projections of the foot will demonstrate the sesamoid bones superimposed on adjacent bony structures. (Bontrager and Lampignano, 6th ed., p. 231)

Answer 79

reduce patient skin dose. EXPLANATION: The x-ray tube's glass envelope and oil coolant are considered inherent filtration. Thin sheets of aluminum are added to make a total of 2.5 mm Al equivalent filtration in equipment operated above 70 kVp. The function of aluminum filtration is to remove from the x-ray beam the soft (long-wavelength) x-ray photons that do not contribute to image formation but simply contribute to patient dose. These soft x-rays penetrate only a small thickness of tissue before being absorbed. (Selman, p 411)

Answer 80

2 and 3 only EXPLANATION: The greater and lesser tubercles are prominences on the proximal humerus separated by the intertubercular (bicipital) groove. The lateral projection of the humerus places the shoulder in extreme internal rotation with the epicondyles perpendicular to the IR and superimposed. The lateral projection of the humerus should demonstrate the lesser tubercle in profile. The AP projection of the humerus/shoulder places the epicondyles parallel to the IR and the shoulder in external rotation and demonstrates the greater tubercle in profile. (Frank, Long, and Smith, 11th ed., vol. 1, p. 176)

Answer 81

30-degree oblique EXPLANATION: Lumbar articular facets, forming the apophyseal joints, are demonstrated in the oblique position. L1 through L4 are best demonstrated in a 45-degree oblique, while L5-S1 are best seen in the 30-degree oblique (up to 60° oblique could be required). The AP axial projection is used to demonstrate an AP projection of L5-S1. (Bontrager and Lampignano, 7th ed., p. 334)

Answer 82

3 only EXPLANATION: When the arm is placed in the AP position, the epicondyles are parallel to the plane of the cassette and the shoulder is placed in external rotation. In this position, an AP projection of the humerus, elbow, and forearm can be obtained; it places the greater tubercle of the humerus in profile. For the lateral projection of the humerus, the arm is internally rotated, elbow somewhat flexed, with the back of the hand against the thigh and the epicondyles superimposed and perpendicular to the IR. The lateral projections of the humerus, elbow, and forearm all require that the epicondyles be perpendicular to the plane of the cassette. (Ballinger & Frank, pp 161, 164)

Answer 83

2.8 mR/min EXPLANATION: The relationship between x-ray intensity and distance from the source is expressed in the inverse-square law of radiation. The formula is EXPLANATION: Substituting known values: EXPLANATION: Thus, x = 2.88 mR/min at 5 m. Distance has a profound effect on dose received and, therefore, is one of the cardinal factors considered in radiation protection. As distance from the source increases, dose received decreases. (Bushong, 8th ed., pp. 68–70)

Answer 84

Lateromedial weight-bearing lateral EXPLANATION: Weight-bearing lateral projections of the foot are requested often to evaluate the longitudinal arch structure of the foot. The patient stands on a small platform. The x-ray cassette is placed between the feet, in a slot provided on the platform, with the top of the cassette against the medial aspect of the foot. The CR is directed to enter the lateral aspect of the foot perpendicular to the base of the fifth metatarsal and to exit the medial side of the foot. (Frank, Long, and Smith, 11th ed., vol. 1, pp. 268–269)

Answer 85

1, 2, and 3 EXPLANATION: For negligent tort liability, four elements must be present—duty (what should have been done), breach (deviation from duty), injury sustained, and cause (as a result of breach). The assessment of duty is determined by the professional standard of care. Examples of negligent torts include patient injury as a result of a fall while unattended on an x-ray table, in a radiographic room, or on a stretcher without side rails or safety belt. Radiographing the wrong patient and radiographing the opposite limb are other examples of negligence. If patient injury results from misperformance of a duty in the routine scope of practice of the radiographer, most courts will apply res ipsa loquitur; that is, "the thing speaks for itself." If the patient is obviously injured as a result of the radiographer's actions, it becomes the radiographer's burden to disprove negligence. In many instances, the hospital and/or radiologist also will be held responsible according to respondeat superior, or "the master speaks for the servant." (Adler and Carlton, 4th ed., p. 374)

Answer 86

Reflective layer EXPLANATION: The PSP storage plate within the IP has a layer of europium-activated barium fluorohalide (BaFX: Eu2+; X = halogen) mixed with a binder substance. This layer serves as the image receptor when exposed in the traditional manner; it looks very much like an x-ray cassette intensifying screen. The barium fluorohalide is usually granular or turbid phosphors. Other examples of turbid phosphors are gadolinium oxysulfide and rubidium chloride. "Needle"-shaped, or columnar phosphors (usually cesium iodide), have the advantage of better x-ray absorption and less light diffusion. Just under the barium fluorohalide layer is a reflective layer that helps direct emitted light up toward the CR reader. Below the reflective layer is the base, behind that is an antistatic layer, and then the lead foil to absorb backscatter. Over the top of the barium fluorohalide is a protective layer.

Answer 87

1, 2, and 3 EXPLANATION: All these symptoms are related to a respiratory reaction. There also may be dyspnea, asthma attack, or cyanosis. The patient who has received contrast media should be watched closely. If any symptoms arise, the radiologist should be notified immediately. (Adler and Carlton, 4th ed., p. 331)

Answer 88

Its 12-cm. mode EXPLANATION: Most image-intensifier tubes are either dual-field or trifield, indicating the diameter of the input phosphor. When a change to a smaller-diameter mode is made, the voltage on the electrostatic focusing lenses is increased, and the result is a magnified but dimmer image. The milliamperage will be increased automatically to compensate for the loss in brightness with a magnified image, resulting in higher patient dose in the smaller-diameter modes. (Bushong, 10th ed., p. 407)

Answer 89

1 only EXPLANATION: If the SID is above or below the recommended focusing distance, the primary beam will not coincide with the angled lead strips at their lateral edges. Consequently, there will be absorption of the primary beam termed grid cutoff. If the central ray is off-center longitudinally, there will be no ill effects. If the central ray is off-center side to side, the lead strips are no longer parallel with the divergent x-ray beam, and there will be loss of density owing to grid cutoff. Central ray angulation in the direction of the lead strips is appropriate and will not cause grid cutoff. Central ray angulation against the direction of the lead strips will cause grid cutoff. (Selman, 9th ed., pp. 239–242)

Answer 90

1 and 2 only EXPLANATION: Grid ratio compares the height of the lead strip to the distance between the lead strips. Focused grids have their lead strips angled so as to parallel the divergent x-ray beam. The higher the grid ratio, the greater the grid's efficiency in absorbing scattered radiation before it reaches the image receptor—but the more critical the centering and distance specifications. Although higher ratio focused grids absorb more SR they have a narrower focal range (focusing distance) and grid/tube centering becomes much more critical. Focused grids must not be accidentally inverted—to do so would cause the lead strips to be placed exactly in the path of the lead strips (grid cutoff), everywhere but in the center of the grid. (Ballinger & Frank, vol 3, p 235)

Answer 91

Tangential patella EXPLANATION: In the tangential (sunrise) projection of the patella, the CR is directed parallel to the longitudinal plane of the patella, thereby demonstrating a vertical fracture and providing the best view of the patellofemoral articulation. The AP knee projection could demonstrate a vertical fracture through the superimposed femur, but it does not demonstrate the patellofemoral articulation. The tunnel view of the knee is used to demonstrate the intercondyloid fossa. (Frank, Long, and Smith, 11th ed., vol. 1, pp. 324–325)

Answer 92

15 degrees toward the side being examined EXPLANATION: When one cheekbone is depressed, a tangential projection is required to "open up" the zygomatic arch and draw it away from the overlying cranial bones. This is accomplished by placing the patient in the SMV position, rotating the head 15 degrees toward the affected side, and centering to the zygomatic arch. A 30-degree rotation places the mandibular shadow over the zygomatic arch. (Frank, Long, and Smith, 11th ed., vol. 2, pp. 364–365)

Answer 93

Anoxic EXPLANATION: Tissue is most sensitive to radiation when it is oxygenated and least sensitive when it is devoid of oxygen. Anoxic refers to tissue without oxygen; hypoxic refers to tissue with little oxygen. Anoxic and hypoxic tumors typically are avascular (with little or no blood supply) and, therefore, more radioresistant. Oxygen at a higher level than atmospheric pressure (hyperbaric) can be used to treat infections and promote healing, as well as treat carbon monoxide poisoning. (Bushong, 10th ed., p. 481)

Answer 94

Diarthrotic joint EXPLANATION: The radiograph is a PA projection of the hand and wrist; an oblique projection of the thumb is obtained. The letter T is pointing out the first carpometacarpal joint, formed by the base of the first metacarpal and the trapezium. This is classified as a saddle-type diarthrotic joint. Diarthrotic joints are freely movable joints and the most plentiful type of joint in the human body. Amphiarthrotic joints are partially movable; synarthrotic joints are immovable. (Frank, Long, and Smith, 11th ed., vol. 1, p. 73)

Answer 95

1 and 2 only EXPLANATION: Blowout fractures of the orbital floor are caused by a direct blow to the eye. The orbital floor is caused to collapse; this carries the inferior rectus muscle through the fracture site and into the maxillary sinus. Diplopia (double vision) often results. Blowout fractures are well demonstrated with the modified Waters method (modified parietoacanthal projection) and with CT studies. A modified parietoacanthal projection with the lips-meatal line (LML) perpendicular and the OML 55degrees to the IR will demonstrate the orbital floor. The zygoma usually is not involved with a blowout fracture but rather with a tripod fracture. (Bontrager and Lampignano, 7th ed., p. 422)

Answer 96

1 and 2 only EXPLANATION: Use of high osmolality (ionic) water-soluble contrast media can result in adverse physiological effects. These effects are usually classified as mild, moderate, or severe. Mild effects include warmth, itching, flushing, nausea, pallor, hives, anxiety, chills. Mild reactions are usually temporary and transient. The radiographer should reassure the patient and should observe and communicate with the patient to be certain that the mild reaction is resolved. Treatment is usually not necessary for mild reactions. Moderate adverse effects include hypertension, dyspnea, hypotension, bronchospasm. Patients must be closely observed for possible worsening of reaction; treatment might be required depending on progression of the reaction. Severe reactions include arrhythmia, cardiopulmonary arrest, laryngeal edema. Clearly, severe reactions require immediate recognition and treatment. (Adler and Carlton, 3rd ed, pp 297-298)

Answer 97

1 and 2 only EXPLANATION: Oral administration of barium sulfate is used to demonstrate the upper digestive tract: the esophagus; the fundus, body, and pylorus of the stomach; and the small bowel, consisting of duodenum, jejunum, and ileum. Consistent care must be taken to read and record patient information accurately and correctly. The large bowel is usually demonstrated via rectal administration of barium. (Bontrager, pp 442-443)

Answer 98

The receptor field should be exposed to a uniform X-ray exposure field, followed by visual inspection of the image EXPLANATION: Because digital receptors are re-used, artifacts arising from debris and contaminants such as barium contrast media will show up on subsequent images from the receptor until the problem is corrected. By exposing the receptor to an X-ray exposure field (A) that covers the entire receptor, the resultant image can be inspected for artifacts. Maintenance checks should be conducted by technologists on a regular basis to ensure the production of diagnostic images free from artifacts and maintain patient throughput. If the artifacts cannot be corrected, then the manufacturer or a medical physicist should be contacted to evaluate the equipment (B). Regular maintenance checks should be conducted to proactively detect artifacts prior to exposing patients. Otherwise, potential artifacts may interfere with correct diagnoses (C). Cleaning the surrounding environment (D) to reduce collection of debris that may find its way to the receptor is a good practice. However, detector artifacts caused by debris (or contaminants) cannot be detected prior to patient exposure unless an exposure is made on the receptor and the resultant image is visually inspected. (Seeram, p. 231).

Answer 99

7 ft EXPLANATION: The relationship between x-ray intensity and distance from the source is expressed by the inverse-square law of radiation. The formula is EXPLANATION: Substituting known values: EXPLANATION: Thus, x = 6.5 ft (necessary to decrease the exposure to 6 R/h). Note that in order for the exposure rate to decrease, the distance from the source of radiation must increase. (Bushong, 8th ed., p. 68)

Answer 100

Blur EXPLANATION: Recorded detail is evaluated by how sharply tiny anatomic details are imaged on the radiograph. The area of blurriness that may be associated with small image details is termed geometric blur. The blurriness can be produced by using a large focal spot or by diffused fluorescent light from intensifying screens. The image proper (i.e., without blur) is termed the umbra. Mottle is a grainy appearance caused by fast imaging systems. (Selman, 9th ed., pp. 206–207)

Answer 101

2 and 3 only EXPLANATION: Handwashing remains the single most effective way to prevent spread of microorganisms. Health care workers should wash their hands before and after each patient. Radiographers must wash their hands after contact with patients with known communicable diseases, after contact with blood/body fluids, and before starting any procedure on patients who are at risk of infection (i.e., immunosuppressed). (Ballinger and Frank 10th ed Vol 1, p 15)

Answer 102

rad EXPLANATION: Rad is an acronym for radiation absorbed dose; it measures the energy deposited in any material; that is, it is equal to 100 ergs of energy per gram of any absorber. Roentgen is the unit of exposure; it measures the quantity of ionizations in air. Rem is an acronym for radiation equivalent man; it includes the RBE specific to the tissue irradiated and therefore is a valid unit of measurement for the dose to biologic tissue. (Bushong, p 24)

Answer 103

Spontaneous abortion EXPLANATION: Irradiation during pregnancy, especially in early pregnancy, is avoided because the fetus is particularly radiosensitive during the first trimester. Especially high-risk examinations include pelvis, hip, femur, lumbar spine, cystograms and urograms, upper gastrointestinal (GI) series, and barium enema examinations. During the 2nd to 10th week of pregnancy (ie, during major organogenesis), fetal anomalies can be produced. Skeletal and/or organ anomalies can appear if irradiation occurs early on, and neurologic anomalies can be formed in the latter part; mental retardation childhood malignant diseases can also result from irradiation during the first trimester. Fetal irradiation during the second and third trimester, with sufficient dose, can cause some type of childhood malignant disease. Fetal irradiation during the first 2 weeks of gestation will most likely result in embryonic resorption or spontaneous abortion. It must be emphasized that the likelihood of producing fetal anomalies at doses below 20 rad is exceedingly small and that most general diagnostic examinations are likely to deliver fetal doses of less than 1 to 2 rad. (Bushong, p 561)

Answer 104

Reduced patient dosage EXPLANATION: When using photospot camera film, there is reduced patient dosage (C). In fact, dosage is at least half that used with cassette-loaded spot film (C). A smaller anatomical image size (A) is produced with photospot camera film when compared to cassette-loaded spot film. The photospot camera provides adequate image quality without interruption of the fluoroscopic examination and an increased rate of exposures (B) of up to 12 images per second. With cassette-loaded spot films, the fluoroscopic examination must be interrupted while the film moves into position, the mA is switched from low to high mA, and the rotor speed is increased, which can delay the exposure for a couple of seconds. Both photospot camera film and cassette-loaded spot film must be chemically processed in a darkroom (D). (Bushong, 9th ed., p. 358).

Answer 105

1 only EXPLANATION: Dual x-ray absorptiometry (DXA) imaging is used to evaluate bone mineral density (BMD). It is the most widely used method of bone densitometry—it is low dose, precise, and uncomplicated to use/perform. DXA uses two photon energies—one for soft tissue and one for bone. Since bone is more dense and attenuates x-ray photons more readily, their attenuation is calculated to represent the degree of bone density. Bone densitometry, DXA, can be used to evaluate bone mineral content of the body, or part of it, to diagnose osteoporosis or to evaluate the effectiveness of treatments for osteoporosis. (Ballinger & Frank, vol 3, pp 488–489)

Answer 106

lower and more medial EXPLANATION: The four types of body habitus describe differences in visceral shape, position, tone, and motility. One body type is hypersthenic, the very large individual with short, wide heart and lungs, high transverse stomach and gallbladder, and peripheral colon. The sthenic individual is the average, athletic, most predominant type. The hyposthenic patient is somewhat thinner and a little more frail, with organs positioned somewhat lower. The asthenic type is smaller in the extreme, with a long thorax, a very long, almost pelvic stomach, and a low medial gallbladder. The asthenic colon is medial and redundant. (Frank, Long, and Smith, 11th ed., vol. 1, p. 64)

Answer 107

1, 2, and 3 EXPLANATION: All three factors can affect radiographic contrast. The type of chemistry used in the automatic processor and especially the temperature of the solution can have a big impact on the resulting image contrast. As temperature increases, contrast decreases. Since pathology can alter the degree of attenuation of the x-ray beam, it can affect contrast. The type of pathology will determine how contrast is affected. An additive pathology such as Paget's disease will increase contrast, while a destructive disease such as osteoporosis will decrease contrast. OID can affect contrast when it is used as an air gap. If a 6-inch air gap (OID) is introduced between the part and the IR, much of the scattered radiation emitted from the body will not reach the IR; the air gap thus acts as a grid and increases image contrast. (Carlton & Adler, pp 397–398)

Answer 108

begin external chest compressions at a rate of at least 100 compressions/min. EXPLANATION: The long tradition of ABC'c (airway, breathing, chest compressions) has been changed to CAB (chest compressions, airway, breathing). If the victim is unable to be roused, the rescuer should start with 30 compressions, at a rate of 100 compressions per minute. The victim's airway should then be opened and rescue breathing begun. This is accomplished by tilting back the head and lifting the chin. However, if the victim may have suffered a spinal cord injury, the spine should not be moved, and the airway should be opened using the jaw-thrust method. The rescuer next listens to breathing sounds and watches for the rise and fall of the chest to indicate breathing. If there is no breathing, the rescuer pinches the victim's nose and delivers two full breaths via mouth-to-mouth rescue breathing. (Adler and Carlton, 5th ed., p. 256)

Answer 109

1 only EXPLANATION: The tissue weighting factor (Wt) represents the relative tissue radiosensitivity of irradiated material (e.g., muscle vs. intestinal epithelium vs. bone). The radiation weighting factor (Wr) is a number assigned to different types of ionizing radiations in order to better determine their effect on tissue (e.g., x-ray vs. alpha particles). The Wr of different ionizing radiations depends on the LET of that particular radiation. The following formula is used to determine effective dose E: EXPLANATION: (Bushong, 8th ed., p. 556)

Image acquisition and Evaluation Flashcards

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