P2

Question 1

There are instruments designed to detect radiation or to measure radiation or both.
Those designed to detect usually operated in a pulse or rate mode and are used to detect the presence of radiation.
They will _____ when radiation is detected.
The response measurement is in ____.

Answer 1

chirp or tick, mR/hr or R/hr

Question 2

Units that measure the intensity of radiation are called

Answer 2

dosimeters

Question 3

Dosimeters operate in the ____ where they accumulate the exposure and respond to the total exposure. The response is in ___.

Answer 3

integrate mode, mR or R

Question 4

The earliest dosimeter was the ____. It is still popular today though there are some newer technologies that have some better characteristics.

Answer 4

film badge

Question 5

Types of Dosimeters

Answer 5

Film Badge (photographic emulsion)
Gas filled detectors
• Ion Chambers
•Geiger-Muller Counter
• Proportional Counters
Thermoluminescence dosimeter (TLD)
Optically stimulated dosimeter (OSL) Scintillation detector

Question 6

• Limited range < 10 mR not measured.
• Energy Dependent
• Must be changed monthly
• Popular for personnel monitoring
• Must be worn with proper side to exposure.
• Sensitive to heat never leave in a car.

Answer 6

Film Badges

Question 7

• Can measure a wide range of radiation intensities from 1 mR/hr to several thousand r/hr.
• Used to assay radionuclides in nuclear
medicine.

Answer 7

Gas-Filled Detectors

Question 8

They are used as laboratory instruments and meters to detect very low radiation intensities.

Answer 8

Gas-filled Detectors

Question 9

The _____ is the basis for gas filled detectors.

Answer 9

ionization of gas

Question 10

Some materials glow when heated. This is referred to as ____

Answer 10

thermoluminesecence

Question 11

Some materials will glow brightly after exposure to ionizing radiation and subsequently heated. This is the principle of operation of the _____.

Answer 11

Thermoluminescence dosimeter (TLD)

Question 12

TLD was discovered on ____ at the ____.

Answer 12

1960, University of Wisconsin

Question 13

most commonly used TLD material

Answer 13

Lithium fluoride

Question 14

It is relatively sensitive and can measure doses as low as 5 mrad with modest accuracy and at exposures greater then 10 rad is accurate to better than 5%.

Answer 14

Lithium fluoride

Question 15

-activated with manganese
-is more sensitive and can measure less than 1 mrad
- used for environmental monitoring

Answer 15

Calcium Fluoride

Question 16

-They are reusable
-More accurate
-Not sensitive to heat or humidity
-Can be changed less frequently i.e.
quarterly

Answer 16

TLD

Question 17

Optically Stimulated Luminescence was discovered in the late ___ by ____

Answer 17

1990’s, Landauer

Question 18

uses aluminum oxide at the radiation detector.

Answer 18

Optically Stimulated Luminescence

Question 19

is superior to TLD and Film Badges
because:
— Accurate to 1 mrad within +/-1 mrad.
— Reanalysis is possible to confirm report.
— Gain qualitative information about exposure conditions.
Wide range
Long Term stability

Answer 19

OSL

Question 20

are the basis of nuclear medicine gamma cameras used for bone scans.

Answer 20

Scintillation detectors

Question 21

-are used in computed tomography scanners
-are more sensitive than Geiger-Muller dosimeters

Answer 21

Scintillation detectors

Question 22

• Radiation dose is measured in

Answer 22

units of RADS (GyT).

Question 23

Radiation exposure is measured in

Answer 23

Roentgens (GyA)

Question 24

• When the radiation exposure is to a chiropractor, radiologic technologist or radiologist, the proper unit is

Answer 24

rem (Sv)

Question 25

The ___ is the unit of effective dose and is used for radiation protection purposes.

Answer 25

rem (Sv)

Question 26

The ____ identifies the biologic effectiveness of the radiation energy absorbed.

Answer 26

rem (Sv)

Question 27

The recommended dose for radiology radiation workers is

Answer 27

50 mSv/year (5000 mrem/year)

Question 28

typically receive more radiation exposure than technologists due to fluoroscopy and being closer to the source of radiation.

Answer 28

Medical radiologist

Question 29

is the primary source of the highest occupational exposure.

Answer 29

Fluoroscopy

Question 30

Patient exposure to diagnostic x-rays is usually reported in one of three ways.

Answer 30

Entrance skin exposure Gonadal dose Dose to the bone marrow

Question 31

is most often referred to as the patient dose. It is widely used because it is easy to measure and reasonably accurate estimates can be made in the absence of measurements.

Answer 31

Entrance Skin Exposure

Question 32

can be used to measure the ESE. Accurate to 5%

Answer 32

TLD

Question 33

• A ___ can be used to estimate exposure. Accurate to perhaps 50%.

Answer 33

nomogram

Question 34

is the average radiation dose to the entire active bone marrow.

Answer 34

mean marrow dose

Question 35

If 50% of the marrow was exposed to 25mrad, the mean marrow exposure would be

Answer 35

12.5 mrad.

Question 36

The ____ is the dose that, if received by every member of the population, would produce the total genetic effect on the population as the sum of the individual doses actually received.

Answer 36

Genetically Significant dose

Question 37

There are two areas of special imaging that are important sources of patient exposure are:

Answer 37

-Mammography -Computed Tomography

Question 38

There are two forms of mammography used today:

Answer 38

screen-film and digital mammography.

Question 39

Mammography is done using ___ with an ESE of about ____

Answer 39

26 kVp, 800 mR/view

Question 40

Radiographic grid ratios of ____ are used for most screen film mammograms.

Answer 40

4:1 or 5:1