chapter 10 (x ray interaction with matter)

Question 1

As Z _____, the probability of Compton scatter ____.

Answer 1

increases, remains the same

Question 2

At energies less than ____ is the only time coherent scatter interactions are somewhat probable in soft tissue.

Answer 2

15 Kev

Question 3

Compton scatter is directed at (a) ______ angle from the incident beam.

Answer 3

Any

Question 4

When the mass density of the absorber is ____, it results in ____ Compton scatter.

Answer 4

increased, increased

Question 5

K-shell binding energy increases with increasing

Answer 5

atomic number

Question 6

The scattered X-Ray from a Compton interaction usually retains _______ of the energy of the incident X-Ray.

Answer 6

most

Question 7

As kVp _____, the probability of Compton scatter ____

Answer 7

increases, decreases

Question 8

An incident X-Ray interacts with an atom without ionization during ______.

Answer 8

coherent scattering

Question 9

As kVp _____, the probability of coherent scatter ____

Answer 9

increases, decreases

Question 10

At energies greater than ____ Compton scatter interactions become most probable in soft tissue.

Answer 10

25 keV

Question 11

Materials with higher atomic numbers have lower _____.

Answer 11

transmission

Question 12

__________ requires at least a 1.022 MeV X-Ray to occur.

Answer 12

Pair production

Question 13

What is CT used for in PET/CT in nuclear medicine?

Answer 13

It shows better resolution images for anatomy and makes the PET image better

Question 14

Which of the following is not one of the five basic X-Rays interactions with matter?

Answer 14

Bremsstrahlung

Question 15

At ~20 keV, the main X-Ray interaction in soft tissue and bone is ______

Answer 15

photoelectric absorption

Question 16

The two primary forms of X-Ray interaction in the diagnostic range are ______.

Answer 16

Compton scattering and photoelectric absorption

Question 17

Which X-Ray interaction generally involves ejection of an outer shell electron?

Answer 17

Compton scattering

Question 18

There is complete absorption of the incident diagnostic X-Ray photon causing ionization with ________.

Answer 18

photoelectric effect

Question 19

Image fog in diagnostic imaging is caused by

Answer 19

Compton scatter

Question 20

After photoelectric absorption, there will be ______.

Answer 20

a scattered electron

Question 21

A negative contrast agent is ____.

Answer 21

air

Question 22

The addition of scattered X-Rays to the image receptor______

Answer 22

degrades contrast

Question 23

The use of contrast agents increases the amount of __________.

Answer 23

Compton scatter
photoelectric absorption
differential absorption
(All of the above)

Question 24

X-Rays transmitted without interaction contribute to _______.

Answer 24

the radiographic image

Question 25

Radiographic contrast is ________.

Answer 25

the difference in attenuation between adjacent areas

Question 26

The beam exiting the patient is mostly ______.

Answer 26

high energy X-Rays

Question 27

Radiographic contrast depends on ________.

Answer 27

kVp
tissue thickness
tissue density
(all of the above)

Question 28

Higher energy X-Ray beams have lower ______ than X-Ray beams with lower energy.

Answer 28

attenuation

Question 29

Barium and iodine are good contrast agents because of their _________.

Answer 29

high atomic number

Question 30

Only at the highest X-Ray energies, around 10 MeV, can ____ take place.

Answer 30

photodisintegration

Question 31

About ____ of the incident beam from the X-Ray tube contributes to the finished image.

Answer 31

0.5%

Question 32

Differential absorption is dependent on the ________.

Answer 32

kVp of the exposure.
atomic number of the absorber.
mass density of the absorber.
(All of the above.)