Chapter 20

Question 1

computed tomography (CT)

Answer 1

diagnostic x-ray procedure where a cross-sectional image of a specific body segment is produced; newer CT scanners can create 3D images as well

Question 2

contrast studies

Answer 2

radiopaque materials (contrast media) are injected to obtain contrast between tissues that would be indistinguishable from one another

Question 3

gamma camera

Answer 3

machine to detect gamma rays emitted from radiopharmaceuticals during scanning for diagnostic purposes

Question 4

gamma rays

Answer 4

high-energy rays emitted by radioactive substances used in tracer studies

Question 5

half-life

Answer 5

time required for a radioactive substance to lose half its radioactivity by disintegration

Question 6

interventional radiology

Answer 6

therapeutic or diagnostic procedures performed by a radiologist; examples are a needle biopsy of a mass and drainage of an abscess, typically under the guidance of CT, ultrasound, or fluoroscopy

Question 7

in vitro

Answer 7

process, test, or procedure is performed, measured, or observed outside a living organism, often in a test tube

Question 8

in vivo

Answer 8

process, test, or procedure is performed, measured, or observed within a living organism

Question 9

ionization

Answer 9

transformation of electrically neutral substances into electrically charged particles; x-rays cause ionization of particles within tissues

Question 10

magnetic resonance imaging (MRI)

Answer 10

magnetic field and radio waves produce sagittal, coronal, and axial images of the body

Question 11

nuclear medicine

Answer 11

medical specialty that uses radioactive substances (radionuclides) in the diagnosis and treatment of disease

Question 12

positron emission tomography (PET)

Answer 12

positron-emitting radioactive substances given intravenously create a cross-sectional image of cellular metabolism based on local concentration of radioactive substance; give information about metabolic activity

Question 13

radioimmunoassay

Answer 13

test combines radioactive chemicals and antibodies to detect minute quantities of substances in a patient’s blood

Question 14

radioisotope

Answer 14

radioactive form of an element substance; radionuclide

Question 15

radiolabeled compound

Answer 15

radiopharmaceutical; used in nuclear medicine studies

Question 16

radiology

Answer 16

medical specialty concerned with the study of x-rays and their use in the diagnosis of disease; includes other forms of energy, such as ultrasound and magnetic waves

Question 17

radiolucent

Answer 17

permitting the passage of x-rays; structures appear black on x-ray images

Question 18

radionuclide

Answer 18

radioactive form of an element that gives off energy in the form of radiation; radioisotope

Question 19

radiopaque

Answer 19

obstructing the passage of x-rays; structures appear white on the x-ray images

Question 20

radiopharmaceutical

Answer 20

radioactive drug (radionuclide plus chemical) that is administered safely for diagnostic and therapeutic purposes; a radiotracer

Question 21

scan

Answer 21

image of an area, organ or tissue of the body obtained from ultrasonography, radioactive tracer studies, computed tomography, or magnetic resonance imaging

Question 22

scintigraphy

Answer 22

diagnostic nuclear medicine test using radiopharmaceuticals and gamma cameras to create images

Question 23

single photon emission computed tomography (SPECT)

Answer 23

radioactive tracer is injected intravenously and a computer reconstructs a 3D image based on a composite of many views

Question 24

tagging

Answer 24

attaching a radionuclide to a chemical and following its path in the body

Question 25

tracer studies

Answer 25

radionuclides are used as tags, or labels, attached to chemicals and followed as they travel through the body

Question 26

ultrasonography (US, U/S)

Answer 26

diagnostic technique that uses high-frequency sound waves to produce images of the body

Question 27

ultrasound transducer

Answer 27

handheld device that sends and receives ultrasound signals

Question 28

uptake

Answer 28

rate of absorption of a radionuclide into an organ or tissue

Question 29

ventilation-perfusion study (V/Q scan)

Answer 29

consists of two scans: a ventilation scan performed using an inhaled radiopharmaceutical and a perfusion scan using an intravenously injected radiopharmaceutical; used to evaluate for pulmonary embolism