Ch. 22 diagnostic imaging CMA review

Angiography

X-ray visualization of blood vessels after the intravascular introduction of contrast media.

nuclear medicine

a branch of medicine that uses radionuclides in the diagnosis and treatment of disorders.

radionuclide

a chemical substance (isotope) that exhibits radioactivity. a gamma camera is used to pick up its radioactive signals as it gathers in organs or tissues.

xeroradiography

a diagnostic x-ray technique in which an image is produced electrically rather than chemically. it permits shorter exposure times and lower radiation levels than is used primarily for mammography.

digital x-ray

a form of X-ray imaging in which digital X-ray sensors are used instead of traditional photographic film. they reduce processing time and also require less radiation to produce images

thermography

a heat-sensing technique used for the detection of tumors. an infrared camera is used, which records variation in skin temperature. warm areas appear light, and cool areas appear dark. tomography is able to view a cross section of an organ.

cassette

a light-proof container that holds X-ray film and serves to intensify the image

magnetic resonance imaging (MRI)

a noninvasive diagnostic modality (way in which doctors diagnose illness or disease) allowing visualization of anatomic structures without using radioactive X-rays. it is contraindicated in patients with pacemakers or metallic prostheses.

radioiodine

a radioactive isotope of iodine used in nuclear medicine and radiotherapy. it is used especially in the treatment of some thyroid conditions.

computer tomography (CT)

a radiographic technique that allows a detailed 360-degree cross section of tissue structure. it is a painless procedure.

noninvasive procedure

a radiological test that does not require the insertion of devices or the breaking of skin. examples include standard X-rays and ultrasonography.

stereoscopy

a rarely used X-ray procedure to study (primarily) the skull.

radiation exposure badge

a sensitized piece of film, in a holder, that indicates the amount of radiation to which the individual has been exposed. the badge should be checked regularly. it is also called a dosimeter.

x-ray film

a special material with a sensitive emulsion layer that reacts when it is exposed to radiation and thereby produces an image. Single-emulsion film is used to create images of the extremities and the breasts.

hysterosalpingography

a special x-ray procedure that utilizes a contrast dye to examine the uterus and fallopian tubes.

roentgen

a unit used to measure X-ray dosage in air

rem

a unit used to measure the X-ray dosage in human beings. it is abbreviation of roentgen equivalent in man.

rad

a unit used to measure the actual absorbed dose of radiation

labeling of the film

-put name of patient -name of doctor who referred -date

tomography

also called sectional imaging and body-section radiography. it allows the visualization of an organ or the body in cross-section.

X-Ray

an electromagnetic wave with a high energy level and short wavelength that can penetrate solid objects. X-rays can be used in diagnosis and therapy.

scan

an image produced on film by a sweeping beam of radiation

radiograph

an image recorded on film that has been exposed. An older term for radiograph is roentgenogram, named after the discoverer of X-rays, Wilhelm conrad roentgen.

film fog

an unwated increase in the density of the emulsion either before or after exposure to radiation. heat, light, chemicals, and extraneous radiation can produce fogging which appears as darkened areas on the finished radiograph

preparation for arthrography

ask patients about possible allergies to contrast media, iodine, or shellfish. no other special preprocedure preparation is necessary.

preparation for tomography or CT scan

ask the patient about possible allergies to contrast media, iodine, or shellfish. the patient must lie still while the scans are taken. for a CT scan, the pt may breathe normally, but it is necessary for the patient to hold his or her breath for a tomograph.

preparation for cholecystography

ask the patient about possible allergies to contrast media, iodine, or shellfish. the patient should eat a fat-free dinner the evening before the examination and should not smoke or have any foods or liquid after midnight.the oral contrast medium should be taken 2 hours after dinner; tablets should be taken 5 minutes apart.

preparation for barium enema or IVP

ask the patient about possible allergies to contrast media, iodine, or shellfish. the patient should follow an all-liquid diet starting the morning before the procedure and should take a prescribed amount of electrolyte solution or other lazative on a specified schedule.

preparation for mammography

avoiding caffeine for a week or 10 days prior will reduce the possibility of swelling and soreness that will heighten discomfort. the patient should not use deodorant, powder, lotion, or perfume on the underarm area or breasts before the examination.

radioactive

capable off emitting radiant energy; or giving off radiation as the result of the disintegration of the nucleus of an atom.

ultrasound

directs high-frequency sound waves through the skin and produces an image based on the echoes. ultrasound has many medical applications, including fetal monitoring, imaging of internal organs, and color imaging of blood vessels.

nuclear energy

energy produced by fission of an atomic nucleus

exposure

exposure to radiation is cumulative, meaning that it adds up to a total dosage over the years. the amount of exposure is measured in units called roentgens

artifacts

extraneous marks and areas of increased or decreased density on film. artifacts interfere with diagnostic value of the radiograph

X-ray machine

has four basic parts: table, control panel, X-ray tube, and high-voltage generator. the table is usually adjustable. the most important part of the machine is the tube.

postprocedural care

have the patient assume a comfortable position while the films are being developed. if the films are satisfactory, have the pt get dressed and give them instructions on how to get the test results.

preparation for MRI

if a contrast medium will be used, ask the patient about possible allergies to contrast contrast media, iodine, or shellfish. ask whether any internal metalic material are present, such as a pacemaker, clips, shunts, heart valves, or slivers or chips from working with metal. patients should avoid caffeine for 4 hours before the examination, and they should not wear eye makeup during the procedure.

positron emission tomography (PET)

involves the injection of isotopes combined with other substances, such as glucose. positrons are emitted and processed by a computer and displayed on a screen. it is useful for diagnosis of brain-related conditions, such as epilepsy and Parkinson's disease.

adverse effects of contrast media

oral agents may cause skin rash, vomiting, diarrhea, abdominal pain, or constipation. IV agents can cause urticaria (rash), skin reddening, anaphylaxis, or death. some individuals have allergies to iodine.

positions

patients need to be positioned in different ways, depending on the specific body part being x-rayed. the most common positions for X-rays are anteroposterior, posteroanterior, oblique, and lateral.

filing of films

place in a film-filing envelope, and file the envelope in the correct place in the filing cabinet.

ionizing radiation

radiation that causes ionization in the tissues that absorb it.

teletherapy

radiation therapy administered by a machine that is positioned at some distance from the patient. teletherapy permits deeper penetration and is used primarily for deep tumors. it is done on an outpatient basis.

fluoroscopy

radiological study of moving body structures, performed by a radiologist, that allows both structural and functional visualization of internal body structures directly on a screen. a contrast medium is needed. it is also called radioscopy.

mammography

radiological study of the breast. it is used for the early diagnosis of breast cancer. -it can detect breast cancer 2 years before it can be palpated by hand

cholecystography definition and how long does this procedure take?

radiological study of the gallbladder, not as frequently done as in the past. the preceding evening meal must be low fat, and on oral contrast medium is taken 12 to 15 hours before the procedure. the exam takes around 15 minutes

sialography how long does this procedure take?

radiological study of the salivary gland duct. the patient sucks on a lemon wedge to open the duct. a catheter is inserted into the duct, and a contrast medium is introduced. the exam takes about 1 to 2 hours.

myelography

radiological study of the spinal cord. the radiologist performs a lumbar puncture, removes some cerebrospinal fluid, and injects some radiopaque, water-soluble contrast medium. it is no longer used very often; tomography and MRI have largely replaced it.

intravenous pyelography (IVP)

radiological study of the urinary system in which a series of X-rays is taken after a contrast medium has been injected into a vein. it is also known as excretory urography.

contrast media

radiopaque substances used in radiography to permit visualization of internal structures. contrast visualization include liquids, powders, and gases. They are administered orally, parenterally, and rectally. A positive contrast medium is more dense than the surrounding tissue. a negative contrast medium is less dense than the surrounding area in the body. barium sulfate and iodine are positive contrast media. air is a negative contrast media.

radiopaque

refers to something that does not permit the passage of X-rays. Bones are relatively radiopaque.

radiographic film

sensitive to x-rays, heat, chemical fumes, light, moisture, and pressure. fresh film must be kept on hand at all times.

retrograde pyelography

similar to IVP, except that the radiologist injects the contrast medium through a urethral catheter and takes a series of x-rays.

cholangiography

similar to the cholecystography and performed by a radiologist. the contrast medium is injected directly into the common bile duct (during gallbladder surgery)

invasive procedure

some radiological tests are invasive in that they require a radiologist to insert a catheter, wire, or other testing device into a patient's blood vessel or organ through the skin or body orifice. all invasive procedures require surgical aseptic technique.

film storage

stored in cool, dry place -best temp is between 60 to 70 F. -the best humidity is between 40% and 60% -do not stack on top of each other

magnetism

the ability of certain materials to attract iron and other metals

absorbed dose

the amount of radiation energy absorbed by tissue

axial projection

the beam is projected at an angle, either cephalad or caudad; also known as a semiaxial projection.

frontal projection

the coronal plan of the body part or entire body is parallel to the film plane; the central ray is perpendicular to both. it is called anteroposterior (supine, or facing the film)

brachytherapy

the implanting of radioactive sources into localized tumor tissues that are to be treated for a specific period of time.

barium meal, or barium swallow

the ingestion of barium sulfate. it is used for the radiographic examination of the esophagus, stomach, and intestinal tract. before the test, the pt should not eat or drink anything for 12 hours.

sensitometry

the measurement or study of how radiographic film responds chemically to radiation exposure and to processing conditions

ionization

the process by which an atom becomes ionized (gains or loses electrons)

oblique projection

the projection is neither front or lateral; this type is also named left or right.

cystography

the radiographic examination of the urinary bladder after the introduction of a radiopaque contrast medium

barium enema

the rectal infusion of barium sulfate, which is retained in the lower intestinal tract during the X-ray studies. it is also called a contrast enema. the digestive tract must be totally empty for this procedure. pt should not eat or drink anything 8 hrs before the test exam except for a cup clear liquid the morning of the test.

Frequency

the repetition rate of electromagnetic radiation measured in hertz.

lateral projection

the sagittal plane is parallel to the film; named for the side of the patient closest to the film (left or right)

radiology

the study of the uses of radioactive substances for visualizing the internal structures of the body in order to diagnose and treat disease. it is divided into three specialties: diagnostic radiology, radiation therapy, and nuclear medicine

radiosensitivity

the susceptibility of cells, tissues, or any living substances to the effects of radiation. also, a biological organism's measure of response to radiation. -immature, nonspecialized cells and cells that are growing rapidly are the most radiosensitive; mature, specialized cells are the most radioresistant.

diagnostic radiology

the use of X-ray technology for diagnostic purposes. it also includes the use of magnetic resonance imaging (MRI), ultrasound, computed tomography (CT), and nuclear medicine technologies, such as positron emission tomography (PET), etc.

radiation therapy

the use of radiation to treat diseases such as cancer by preventing cellular reproduction

contrast

the visible difference between any two areas of radiographic density

arthrography

used for joint conditions. it requires a contrast medium. arthrography is performed by a radiologist and is usually done for knee, shoulder, or hip injuries. it also requires a local anesthetic.

isotopes

variants of a single chemical element that have different atomic weights and different charges