CT Sim

Question 1

ct external gantry components

Answer 1

couch, tilt, emerg off buttons, lasers

Question 2

internal ct components

Answer 2

detector array, x-ray tube

Question 3

ct info recorded by

Answer 3

solid state image detectors or gas filled detectors

Question 4

ct ray is the part of the beam that

Answer 4

falls on one detector

Question 5

ct view is one complete translation generating ?

Answer 5

profile or projection

Question 6

ct image matrix is an image displayed in

Answer 6

rows & columns

Question 7

ct pixel is each cell on the image

Answer 7

matrix

Question 8

ct voxel is each

Answer 8

pixel & slice thickness or volume

Question 9

ct filter back projection is summation method of

Answer 9

reconstructing data; avg linear attn coefficient per pixel

Question 10

ct pitch is the distance traveled by

Answer 10

couch during x-ray tube rotation

Question 11

in inverse planning, planner specifies

Answer 11

desired dose limits & computer produces plan

Question 12

ct contrast is shades of

Answer 12

grey

Question 13

beam hardening artifacts appear and are where

Answer 13

dark bands often near bone

Question 14

ring artifact appears if what’s not working

Answer 14

detector

Question 15

motion artifact appears as

Answer 15

streaks or less resolution or partial volume artifact

Question 16

helical artifact appears as

Answer 16

object shape distortion

Question 17

ct window width (WW) is a range of

Answer 17

’s displayed or the contrast

Question 18

ct window level (WL) represents

Answer 18

central HU of all CT #s w/i the WW

Question 19

incr WW, ? contrast

Answer 19

decr

Question 20

decr WW, contrast

Answer 20

incr

Question 21

incr WL= ? image

Answer 21

darken

Question 22

decr WL= ? image

Answer 22

brighten

Question 23

dicom stands for

Answer 23

digital imaging & communications in medicine

Question 24

scintillation detector contains ? assemblies

Answer 24

crystal photodiode assemblies

Question 25

ct crystal of choice

Answer 25

CdWO4 (Cadmium Tungstate)

Question 26

narrow WW= ? contrast on DRR

Answer 26

incr

Question 27

projection is an intensity pattern created from

Answer 27

linear attn coefficient

Question 28

average ct dose per CT slice ?

Answer 28

1-6 cGy

Question 29

EPID components

Answer 29

cathode tube/tv monitor, charged couple device/TV camera, metallic fluoro screen

Question 30

ct # fat

Answer 30

-100

Question 31

ct pitch determines closeness of

Answer 31

helix

Question 32

high matrix= ? pixel

Answer 32

small

Question 33

small pixel= ? resolution

Answer 33

high

Question 34

high resol= ? noise

Answer 34

high

Question 35

small pixel size = ? noise

Answer 35

more

Question 36

incr mA= ? noise

Answer 36

less

Question 37

incr kvp= less

Answer 37

noise

Question 38

incr FOV= ? noise

Answer 38

less

Question 39

incr pixel size= less

Answer 39

noise

Question 40

incr thickness= ? noise

Answer 40

less

Question 41

ct window level changes

Answer 41

density