Physics 2 test 4

Question 1

ALARA stands for

Answer 1

As Low As Reasonably Achievable

Question 2

Three cardinal principles of x-ray

Answer 2

STD (MAX, MIN, MAX)
Max, Shielding
Min, Time
Max, Distance

Question 3

Exposure rate formula

Answer 3

2rad/mA/time

2)(mA)(time

Question 4

How should thr fluro foot pedal be used?

Answer 4

In pulsating fashion to reduce exposure and anode heating

Question 5

Heat unit formula

Answer 5

(mA)(time)(kV)
single phase
6 phase pulse
12 phase pulse

Question 6

A point source or non-point source follows the inverse square law if the distance from the source is what?

Answer 6

7 times the source diameter

Question 7

If the focal spot of the tube is 3mm, how far do you need to be before the inverse square law applies?

Answer 7

21 mm
(7 times away, 7X3=21)

Question 8

Occupational effective dose is how much of monitor report?

Answer 8

10%

Question 9

Where do you stand in Fluoro?

Answer 9

Stay back
Sides of table
NOT ends
behind other personnel
wear protective apparel

Question 10

The tenth value layer equals…

Answer 10

3.3 hvl

1 TVL= 3.3 HVL

Question 11

What is my year occupational dose limit?

Answer 11

5 Rem a year

would look like 5000 on my report

Question 12

Protective houseing must reduce leakage radiation to

Answer 12

Less than 100 mR/hr at 1m from housing

Question 13

Control panel MUST indicate when tube is energized, kVp & mA meters by what?

Answer 13

Some type of audible notification

Question 14

MUST be an SID indicator provided with what type of accuracy?

Answer 14

2%

Question 15

Collimators MUST be provided witha light beam with what type of accuracy?

Answer 15

2%

Question 16

`PBL (what does is stand for) is REQUIRED to collimate to receptor size with what type of accuracy?

Answer 16

Positive Beam Limitation 2%

Question 17

Total filtration of at least (blank) equivalent when operated above (blank) kVp

Answer 17

2.5 mm Al

70 kVp

Question 18

Total filtration includes…

Answer 18

Glass envelop
Mirrors
Tube housing port
Al filters

Question 19

Reproducibility refers to

Answer 19

Same exposure over and over

Question 20

Reproducibility exposure duplication can have what variance?

Answer 20

5%

Question 21

Linearity refers to

Answer 21

Same mR/mAs using adjucment mA but get the same output

Question 22

Linearity can have what variance?

Answer 22

10%

Question 23

How far should a technologist be able to get away from a portable machine and still shot an exposure?

Answer 23

2.0 meters

6+ feet

Question 24

Fluoro source to skin distance

Answer 24

Can’t be less than 38 cm

30 for mobile c-arm

Question 25

Tabletop Exposure intensity not allowed to exceed:

Answer 25

2.1 R/min/mA at 80 kVp

Question 26

Maximum tabletop intensity | What about with pulsating fluoro (optional high level control)

Answer 26

100 mGy/min (10R/min) | 200 mGy/min (20R/min)

Question 27

What is the primary barrier shielding for scatter requirement?

Answer 27

1/16" Pb equiv to 7 ft; 1/32" Pb equiv there to celling

Question 28

What is the concrete equivelant?

Answer 28

4" of concrete replaces 1/16" Pb

Question 29

``` Radiation weighting factors: how many more times exposure: X & Gamma rays? Protons? Fast Neutrons? Alpha Particles? ```

Answer 29

1 2 5 20

Question 30

Personel Monitoring is with?

Answer 30

Film Dosimetry (photographic emulsion)

Question 31

Intensity/detect contamination is measured with what?

Answer 31

Gas-filled radiation detector (Geiger counter)

Question 32

xrays come from what source?

Answer 32

Cloud

Question 33

Gamma rays come from what source?

Answer 33

Nucleous

Question 34

Alpha particles-what do you know?

Answer 34

Huge External not to worrysome, internal source very worrysome, can't get out of the body Not going to go far before stopped

Question 35

Beta particles-what do you know?

Answer 35

Small | Going to go far before being stopped

Question 36

Scintillation detection-gamma camera uses what to detect rays?

Answer 36

Crystals, like the crystals in our badges | The heat them up and then they give off light, based on the amount of light they give off determins the exposure

Question 37

TLD-Thermoluminescence dosimetery radiation detection-how does it work

Answer 37

Has a poshpor when it's heated up, gives off light. | Lithium Floride crystals, radiolucent can use the same time you're taking an xray won't interfere with image

Question 38

This is nearly tissue-equivalent and relatively sensitive

Answer 38

Lithium Flouride (LIF)

Question 39

An aluminum oxide detector that gives off light proportional to exposure during processing. Based on excitation of electrons during exposure

Answer 39

OSL-Optically Stimulated Luminescence

Question 40

How are OSL's read and how do they work

Answer 40

They're read with a lazer beam they have "stair step" crystals and work sort of like a step wedge. The readout gives you quality and strength of the photon

Question 41

Why are OSL's the most used detector?

Answer 41

Significantly more durable and less sensitive to water, heat and light. Can be worn for 3 months at a time.

Question 42

What is the number one cause of Radiation Exposure?

Answer 42

Diagnostic Repeats

Question 43

Patient dose/skin entrance dose is measured with what and why

Answer 43

TLD, radiolucent, doesn't measure anything in diagnostic range and doesn't interfere with image.

Question 44

Describe a "Mean Marrow Dose"

Answer 44

A dose of radiation given to a portion of the body and then averaged out over entire bone marrow. Used to estimate risk of late effect leukemia to a population

Question 45

GSD (Genetically Significant Dose)

Answer 45

Dose that would produce the same effect on anyone exposed if equal exposure to entire population 1000 people x 0.1 rem= (10 people x 10 rem)+ (990 people x 0 rem)

Question 46

What is the concern in Mammography exposure?

Answer 46

Glandular (not skin dose) accounts for 15% of dose

Question 47

In Mammography when you're using a grid how much more is the dose increased?

Answer 47

Double

Question 48

What type of scanning is CT versus Fluro?

Answer 48

CT is dynamic and increases occupational exposure, fluoro is pulsating

Question 49

What are the fetal exposure limits?

Answer 49

5 mSv or 500 mrem WHOLE durration of pregnancy

Question 50

How quickly can the total exposure inutero be applied?

Answer 50

May not be accumulated faster than 0.5 mSv/month or 50 mrem a month