Midterm Exam

Question 1

What is ALRA?

Answer 1

As low as reasonably achievable

Question 2

Benefits must ______risks of any diagnostic study using ionizing radiation.

Answer 2

Outweigh

Question 3

What are the 2 sources of ionizing radiation?

Answer 3

Natural and manmade

Question 4

What are conditions necessary for x-ray production?

Answer 4

1. Source of electrons

2.means for setting them in a high speed of motion (electricity)

3. Mechanism for decelerating them abruptly (anode)

Question 5

What is the cathode filament?

Answer 5

Milliamperage (mA) source of electrons.

Question 6

What is potential difference during X-ray production?

Answer 6

KVP high speed motion

Question 7

What is the target during x-ray production?

Answer 7

Anode (deceleration)

Question 8

What type of tube is the X-ray tube?

Answer 8

Diode tube. Energy of the beam is expressed in kiloelectrons (keV)

Question 9

What are the 5 ways x-rays interact with matter?

Answer 9

1.Classic scattering (Thompson)
2. Photoelectric interactions
3. Compton scattering
4. Pair production
5. Photodisintergration

Question 10

What is classic coherent scatter?

Answer 10

X-rays with energy less than 10 keV. No energy transferred to patient or matter.

Question 11

What are photoelectric interaction?

Answer 11

Within diagnostic x-ray range. Greatest hazard to patients.

Question 12

What is Compton scatter?

Answer 12

Within diagnostic range. Most radiation exposure to workers.

Question 13

What is pair production?

Answer 13

Nuclear medicine.

Question 14

What is photodisintegration?

Answer 14

X-ray must be greater than 10 MeV. Common in nuclear industry.

Question 15

What are the units of measurement in radiography?

Answer 15

Si units (international system of units)
1. Roentgen-in air
2. Gray- radiation absorbed dose (rad) radiation absorbed in any medium. 1Gy= 100 rad
3. Sievert- radiation equivalent man (rem)
4. Becquerel- curie. Measures activity if radioactive material. (Ci)

Question 16

What is KERMA?

Answer 16

Kinetic energy released in matter.

Question 17

What a radiation standards regulated by?

Answer 17

FDA. (CDRH) center for devices and radiological health.

Question 18

What is the annual whole body effective dose limit for workers?

Answer 18

50 mSv (5 rem)

Question 19

What is the whole body dose equivalent limit for the general population?

Answer 19

5 mSv (0.5 rem)

Question 20

What are the cardinal rules of protection?

Answer 20

TIME. DISTANCE. SHIELDING.

Question 21

What is the laws of Bergonie and Tribondeau!

Answer 21

Bergonie- cells are more radio sensitive during active cell division and when they are primitive in structure and function.

Trubondeau- cells are more radio resistant if they are more specialized in structure and function and do not undergo repeated mitosis.

Question 22

What is indirect hit theory?

Answer 22

Involves irradiation of water and creation of free radicals.

Question 23

What is direct hit theory?

Answer 23

Involves x-ray photon hitting DNA causing genetic damage.

Question 24

What is acute radiation syndrome?

Answer 24

Total body response to high radiation exposure.
1.Prodromal stage. (NVD)
2. Latent period. No symptoms but biological change occurs.
3. Manifest stage. Full effects of radiation felt. Patient dies or gets better.