X-Ray Physics Review part 2

Question 1

What does the autotransformer do?

Answer 1

It provides precise voltage to the filament and high voltage transformer

Question 2

Give another name for the high voltage transformer

Answer 2

step-up transfomer

Question 3

Between autotransformers and high-voltage transformers which has a fixed turns ratio and which is adjustable

Answer 3

The autotransformer is adjustable and the high voltage is fixed (usuall 1000:1)

Question 4

What does the rectifier do?

Answer 4

It converts AC to DC because the xray tube can only operate on DC current

Question 5

Is the filament transformer high voltage or low voltage

Answer 5

low voltage

Question 6

What is the relationship between current (amperage) and voltage (v)?

Answer 6

they are inversely proportional. If current is increased, voltage will be decreased.

Question 7

What type of generator is commonly used in Xray equiptment today?

Answer 7

High Frequency

Question 8

Is the negative side of the x-ray tube the anode or the cathode?

Answer 8

The cathode is the negative side

Question 9

What part of the x-ray tube are the filaments and focusing cup located?

Answer 9

The cathode

Question 10

What are the filaments made of that are inside of the focusing cup of an x-ray tube?

Answer 10

Thoriated Tungsten

Question 11

What changes in the x-ray tube when you select large focal spot vs small focal spot?

Answer 11

The large vs small thoriated tungsten filaments

Question 12

Is the positive side of the x-ray tube the anode or the cathode?

Answer 12

The anode is the positive side of the x-ray tube

Question 13

What is the target for the electrons produced by the cathode?

Answer 13

The anode.

Question 14

Is there actually oil in the x-ray tube?

Answer 14

Yes! dielectric oil is used as an insulator in the x-ray tube. It prevents sparking and is a thermal insulator

Question 15

What x-ray tube component produces thermionic emission when heated?

Answer 15

The filament

Question 16

What is it called when additional electrons cannot be emitted from the filament because too many electrons have already collected around the filament?

Answer 16

The Space Charge Effect

Question 17

The greater the mA the (more or less) electrons form the cloud?

Answer 17

more

Question 18

When the electrons strike the anode they either produce nothing but heat or produce x-rays. What is the probability of each?

Answer 18

99% heat - 1% x-rays

Question 19

What are the two main mechanisms for x-ray production in the x-ray tube?

Answer 19

Bremsstrahlung Radiation (interactions) and Characteristic Radiation (interactions)

Question 20

What common term is Bremsstrahlung radiation known as?

Answer 20

“breaking” radiation

Question 21

Why is bremsstrahlung radiation called “breaking” radiation?

Answer 21

because x-rays are given off when the electron slows or “breaks” as it bends around the nucleus

Question 22

Between bremsstrahlung and characteristic radiation (interactions) which is responsible for the majority of the x-rays produced in the x-ray tube?

Answer 22

Bremsstrahlung

Question 23

Which type of x-ray production involves the ejecting of an electron on the target material?

Answer 23

Characteristic radiation

Question 24

Which type of x-ray production involves the projectile electron bending around the nucleus of the target atom but not actually ejecting a target electron?

Answer 24

Bremsstrahlung Radiatioin

Question 25

True or False - Characteristic radiation is only possible when the incident electron has more energy than the binding energy of the inner shell electron?

Answer 25

True

Question 26

True or False - In characteristic radiation the x-rays are only actually produced when the outer shell electron fill an inner shell vacancy?

Answer 26

True

Question 27

What is the primary technical factor set by the technologist that is responsible for the penetrating power or the QUALITY of the x-ray beam?

Answer 27

kVp

Question 28

What is the 15% rule with reference to kVp and mAs?

Answer 28

That increasing the kVp by 15% is roughly equivalent to doubling the mAs when it comes to density

Question 29

Does increasing mAs increase the number of x-rays produced or the quality of x-rays produced?

Answer 29

increasing mAs increases the number or quantity of x-rays produced

Question 30

Does tube filtration remove low energy photons or high energy photons?

Answer 30

filtration removes the useless low-energy x-ray photons. This is known as beam hardening

Question 31

Does CT use a lot of tube filtration or a little?

Answer 31

CT uses a lot of tube filtration because of the high energies needed

Question 32

What is the benefit of reducing low energy photons by increasing filtration in an x-ray tube?

Answer 32

Increased filtration will remove low energy photons and thus reduce patient dose

Question 33

Which generator will produce a spectrum with the highest average energy? (high frequency, 3 phase 12 pulse, 3 phase 6 pulse, or single phase)

Answer 33

High frequency