Lecture 1: Be a radiology tech in 2 years Flashcards Preview

Radiology > Lecture 1: Be a radiology tech in 2 years > Flashcards

Flashcards in Lecture 1: Be a radiology tech in 2 years Deck (51)
Loading flashcards...
1

Bayesian Analysis plus clinical example

pretest probability affects post-test probability. If you have a strong clinical suspicion of fracture but XR is negative, request further testing.

2

x ray attenuation: definition, function of what 3 variables?

X ray photons are "absorbed" by matter; amount of attenuation depends on: thickness, density of material (function of atomic number), and x ray beam kVp (peak kilovoltage/energy)

3

Xray: does an object of high density appear darker or brighter?

Brighter

4

X ray radiolucency: define

Allows x ray to pass through without absorption, penetrates most easily. Appears dark on XR

5

X ray radiodensity: define

Absorbs x ray beams, appears bright on XR

6

Name a highly radiolucent material

Air, fat

7

Name a material class with high radiodensity

heavy metal

8

Which is more radiolucent: bone or water?

water

9

Which is more radiolucent: contrast or bone?

Bone

10

Which is more radiodense: contrast or bone?

contrast

11

Which is more radiodense: bone or fat?

bone

12

PACS-define

Picture archiving and communication system-a medical imaging technology which provides economical storage of and convenient access to images from multiple modalities (source machine types).

13

DICOM-define

Digital Imaging and Communications in Medicine (DICOM) is a standard for handling, storing, printing, and transmitting information in medical imaging. It includes a file format definition and a network communications protocol.

14

RIS-define

A radiology information system (RIS) is a computerized database used by radiology departments to store, manipulate, and distribute patient radiological data and imagery. The system generally consists of patient tracking and scheduling, result reporting and image tracking capabilities.

15

HIS-define

A hospital information system (HIS) is an element of health informatics that focuses mainly on the administrational needs of hospitals

16

satisfaction of search

phenomenon in which the detection of one radiographic finding interferes with that of others; just because you found something doesn't mean you found everything

17

Hounsfield Units: what modality of imaging? Define.

Measure of attenuation of x ray beam in CT scan

18

Hounsfield units: reference values for water and air

water=0, air=-1000

19

Hounsfeld units: bone, blood, muscle, fat

bone=1000, blood=40, muscle=10-40, fat=-50--100

20

CT scan: 4 types of artifact

Motion, metal, partial volume averaging, beam hardening artifact

21

CT scan motion artifact: example

Cardiac motion (less of an issue with today's fast multislice scanners)

22

CT scan: Partial volume averaging artifact

More of an issue with thicker slices; a substance that occupies several voxels will get "averaged" and look larger and blurrier than it would if it was centered in 1 voxel

23

CT scan: metal artifact

Radiodense structures limits evaluation of adjacent structures, can be minimized by increasing kvp

24

CT scan: beam hardening artifact

Appears like an area of radiolucency (very dark area on scan), low energy portion of the spectrum filtered out,

25

CT contrast

Makes structures more radiodense, therefore brighter and easier to discern on scan. Administered orally, rectally, or intravenously.

26

CT contrast risks

allergic reactions (mild-rash; severe-HOTN, laryngeal swelling, CV collapse); renal failure (creatinine >1,5-1.8); contrast extravasation-contrast leaks out of a ruptured vessel

27

CT scan for pts on dialysis

IV CT contrast OK but not MRI contrast

28

CT scan advantages

fast, high resolution, can be reformatted after scan into 3D image in any plane (multiplanar reformatting MPR)

29

CT scan disadvantages

artifact, risks of IV contrast, RADIATION

30

ionizing radiation-define and risk

electromagnetic waves with the energy to knock an outer shell electron out of valence shell (creates an ion); can result in damage to DNA