Chapter 11+12 Study

Question 1

the protective housing of the tube serves at a prevention of _________ entering the tub to prevent electric shock

Answer 1

high voltage

Question 2

if the luminance of the collimator is good, it will luminate…
all area uncollimated
dark skin
shadows away

Answer 2

all area uncollimated/all skin pigments

Question 3

when in flouro, how is last image hold feature beneficial?

Answer 3

effective dose reduction

Question 4

does beam filtration reduce exposure through removing all low photons or absorbing most of them?

Answer 4

absorbing most

Question 5

most flouro uses what KVP range for adults?

Answer 5

75-110

Question 6

what is the cm minimum distance from skin for the tube in portable?

Answer 6

30 cm

Question 7

when flouro image is amplified, what are some benefits?

Answer 7

increased image brightness, saving of time for the radiologist, patient dose reduction,

Question 8

during a flouro exam, when does the alarm timer go off indicating too long of exposure time?

Answer 8

5 minutes

Question 9

high-level control flouro in interventional procedures results in ____________ entrance exposure rate to allow small or low contrast objects to be seen better

Answer 9

higher

Question 10

what filter would make a foot image exposure uniform?

Answer 10

wedge

Question 11

DR advantages over CR

Answer 11

lower dose
ease of use
immediate results
manipulation of image
less maitence

Question 12

photoconductor is made of..

Answer 12

amorphous selenium

Question 13

dr disadvantages over CR

Answer 13

-dr more expensive
-cr compatible with more traditional system
-multiple cassette sizes with cr
-the psp imaging plates are subject to damage but cheap to replace

Question 14

total filtration of _______ for fixed xray units operating above 70 kvp is the regulatory standard.

Answer 14

2.5mm aluminum equivelant

Question 15

define grayscale

Answer 15

number of shades of gray a digital imaging system can display

Question 16

how many workstations can access a digital radiography image at once?

Answer 16

several at the same time

Question 17

for CR, due to its higher exposure lattitude, grid use for pediatrics is _________________

Answer 17

less necessary than was previously believed

Question 18

luminance is determined by measuring the concentration of light over….

Answer 18

a field of view

Question 19

where is the control panel located? (behind a wall, glass, etc.)

Answer 19

behind a protective barrier with radiation absorbent windows so the patient is visible

Question 20

what is the tabletop commonly made of to be radiolucent and durable?

Answer 20

carbon fiber material

Question 21

how does 1 repeat exposure effect a patient’s dose

Answer 21

double dose in area repeated (skin and gonads if in affected area)

Question 22

what combo of kvp and mas (high/low) is best for pt exposure?

Answer 22

high kvp and low mas

Question 23

girly is pregnant, needs an xray, what do you do to minimize her exposure

Answer 23

sheild abdomen and pelvis if possible,
use technical exposure that is appropriate for body part,
and collimate precisely to avoid retakes and avoid under-collimation

Question 24

according to ACR (American college of radiology), after full consideration of status of pt, including pregnancy, imaging procedures should be (postponed/not postponed)

Answer 24

not postponed

Question 25

why did we stop using sheilds constantly>

Answer 25

to avoid lead getting in image and affecting AEC, and lead obscuring anatomy of interest, and retakes due to these things

Question 26

selective area sheilding used during xray procedures to protect what?

Answer 26

lens of eye breast thyroid

Question 27

what is lowest in radiation effective dose? DEXA XRAY CT MAMMO

Answer 27

DEXA

Question 28

what is the first step ALWAYS in protection of reproductive organs?

Answer 28

collimation precisely done

Question 29

involuntary motion can be attributed to what?

Answer 29

age, breathing pattern/problems, physical discomfort, fear of the exam, mental instability

Question 30

when AEC can't be used for exposure, what should the tech use instead to determine exposure?

Answer 30

standardized technique charts for each unit in facility

Question 31

reducing FOV with collimation effects scatter in what way?

Answer 31

lessens it and increases image quality

Question 32

can bone marrow dose/absorption can/cannot be measured directly>

Answer 32

cannot, only estimated

Question 33

equation for measuring bone marrow / mean marrow dose

Answer 33

average dose * % of bone marrow radiated

Question 34

reasons for bad images can be....

Answer 34

mispositioning, wrong centering, patient motion, incorrect collimation

Question 35

after improvements in dosimetry estimates of the efficacy of shielding with modern equipment and techniques, how are societies modifying shielding practices?

Answer 35

discouraging use of patient gonadal shielding and fetal shielding (effective collimation, no retakes, etc.)

Question 36

define quantum mottle

Answer 36

blotchy image when insufficient photons reach the IR

Question 37

T/F patient motion is a frequent problem in pediatric imaging

Answer 37

true

Question 38

essentially all diagnostic medical procedures result in fetal exposures less than _____ , so that the risk of abnormaility is ______

Answer 38

0.01 Gy; small (very)

Question 39

nonessential radiologic procedures include... 1. chest xray automatically scheduled upon ER admission 2. lumbar spine xray exam for a pre-employment physical/ or any routine health checkup xray that is unjustified 3. whole body CT screening 4. chest xray for TB

Answer 39

all 4

Question 40

analysis of imaging department's repeat rate is helpful how?

Answer 40

provides valuable information for process improvement, helps minimize patient exposure, improves overall performance of the department,

Question 41

which of the following are involuntary motions or clinical manifestations that could cause involuntary motions that cannot be willingly controlled? -chills -tremors -muscle spasms -active withdrawal from drugs -pain

Answer 41

all of them

Question 42

skin surface of patient should be at least ----- cm below the collimator for fixed radiographic material to minimize electron photon interaction with collimator

Answer 42

15

Question 43

define an artifact

Answer 43

unwanted desities in the image that are not part of the patient's anatomy and may negatively affect the ability of a radiologist to interpret the image correctly

Question 44

skin dose

Answer 44

dose to epidermis

Question 45

ESE entrance ___ _____

Answer 45

skin exposure ( can convert to dose by using muliplication factors)

Question 46

TLDs are....

Answer 46

the most sensitive devices used to determine skin dose

Question 47

Genetically significant dose....

Answer 47

equivalent dose to the reproductive organs that if received by every human in a large population, would bring about an identical gross genetic injury to that population.

Question 48

how does the ASRT feel about flouro guided xray positioning?

Answer 48

not worth it due to extra exposure it gives if there was not a repeat image taken should never be used

Question 49

what is the air gap technique

Answer 49

replacement for using a grid, reduces scatter. increase OID to 10 -15 cm from IR to decrease scatter that reaches the detector (Increase SID to avoid magnifying)

Question 50

what type of grid does the air gap technique replacate?

Answer 50

8:1 ratio grid

Question 51

what is high level control flouro

Answer 51

used in intervetional radiology, entrance radiation levels are HIGHER than normal and allows smaller and lower contrast items to be seen USE PULSED MODE

Question 52

maximum tabletop flouro exposure rate without HLC present

Answer 52

10 R/min

Question 53

maximum tabletop flouro exposure rate with HLC present

Answer 53

5 R/min

Question 54

when should a notation be placed in a patients record due to level of skin dose recieved?

Answer 54

is dose was in the range of 1-2 Gy

Question 55

name 4 procedures that require extended flouro time

Answer 55

biliary drainage, urinary or biliary stone removal, stent and filter replacement percuaneous nephrostomy, ERCP, transjugular intrahepatic portosystemic shunt radiofrequency cardiac catheter ablation (Stents, shunts, cholangiographys, angioplasty, veins, draining, urinary ERCP stuff)