Frommer: Radiology for the Dental Professional, 9th Edition

Chapter 01: Ionizing Radiation and Basic Principles of X-Ray Generation

Test Bank

COMPLETION

1.	The amount of heat produced in the x-ray tube is ________ than the amount of radiation produced.

ANS: greater

REF: 15

2.	The release of electrons from the hot tungsten filament at the cathode is called the __________.

ANS: thermionic emission effect

REF: 16

3.	The determination of the size and shape of the x-ray beam is called ________.

ANS: collimation

REF: 33

4.	The quantity of x-ray photons produced is determined by the _________ setting.

ANS: milliamperage

REF: 31

5.	The quality of the x-ray photons is determined by the __________.

ANS: kilovoltage

REF: 30

6.	Because of the alternating current supplied to the x-ray tube it is considered to be _______.

ANS: self-rectified

REF: 22
7.	When designing barriers it is important to remember that x-rays travel in _______ lines.

ANS: straight

REF: 6

MULTIPLE CHOICE

1.	If the useful beam is not centered on the film in the patient’s mouth, the result will be:
a.	foreshortening	
b.	elongation	
c.	collimator cutoff	
d.	overlapping	

ANS: C	REF: 35

2.	A diagnostic film is made at 10 mA and 4 impulses. The exposure that would produce the same image at 5 mA would be:
a.	5 impulses	
b.	10 impulses	
c.	8 impulses	
d.	45 impulses	

ANS: C	REF: 31

3.	Collimator cutoff (cone cutting) is caused by:
a.	improper horizontal angulation	
b.	over filtration	
c.	improper beam film alignment	
d.	improper vertical angulation	

ANS: C	REF: 35

4.	If a radiograph is described as “underpenetrated,” then the error must be:
a.	excessive kVp	
b.	too little mA	
c.	excessive mA	
d.	too little kVp	

ANS: D	REF: 30

5.	Which of the following is used in the high-voltage circuit?
a.	a rectifier	
b.	a step-up transformer	
c.	a step-down transformer	
d.	a fuse	

ANS: B	REF: 25

6.	Ionization occurs:
a.	when an atom gains a neutron	
b.	when the atom has no charge	
c.	when an atom loses a proton	
d.	when an atom loses an electron	

ANS: D	REF: 12

7.	Identify the physicist who discovered x-rays:
a.	Hittorf-Crookes	
b.	Roentgen	
c.	Edison	
d.	Kells	

ANS: B	REF: 9

8.	Examples of particulate radiation include:
a.	alpha particles	
b.	electrons	
c.	neutrons	
d.	all of the above	

ANS: D	REF: 2

9.	The difference in the electromagnetic spectrum between x-rays and visible light lies in the:
a.	wavelength	
b.	frequency	
c.	energy	
d.	subatomic particles	

ANS: A	REF: 2

10.	All of the following are properties of x-rays EXCEPT:
a.	x-rays are invisible	
b.	x-rays travel in wavy lines	
c.	x-rays can penetrate structures	
d.	x-rays can adversely affect human tissue	
ANS: B	REF: 6

11.	Identify the particles that compose the nucleus of an atom:
a.	electrons and photons	
b.	electrons and protons	
c.	protons and neutrons	
d.	neutrons	

ANS: C	REF: 10

12.	The target or focal spot in the x-ray tube can be found at the:
a.	positively charged cathode	
b.	positively charged anode	
c.	negatively charged cathode	
d.	negatively charged anode	

ANS: B	REF: 14

13.	Identify the metal used in the focal spot of the x-ray tube:
a.	tungsten	
b.	molybdenum	
c.	copper	
d.	iron	

ANS: A	REF: 14

14.	The total x-ray energy produced by the collision of the electrons with the target inside the x-ray tube is approximately:
a.	less than 1%	
b.	10%–20%	
c.	50%	
d.	99%	

ANS: A	REF: 15

15.	Pointed, plastic cones are not used in dental radiology because:
a.	the cones are difficult for the practitioner to line up correct anatomic structures	
b.	the cones cause the production of excess secondary and scatter radiation	
c.	the cones require a higher kVp setting on the control panel	
d.	the cones require an increase in the time setting	

ANS: B	REF: 28 | 29

16.	The thickness of aluminum that will reduce the intensity of the x-ray beam by 50% is termed:
a.	half value layer	
b.	filtration	
c.	collimation	
d.	penetrating power	

ANS: A	REF: 30