Deck 6: The X-ray Tube

Question 1

What is the most common cause of tube failure?

A) Cracked anode
B) Loose bearings
C) Pitted anode
D) Tungsten vaporization

Answer 1

Tungsten vaporization

Question 2

The filament is made of __________.

A) graphite
B) tungsten
C) copper
D) molybdenum

Answer 2

tungsten

Question 3

A dual focus tube has two _______.

A) anodes
B) filaments
C) rotors
D) stators

Answer 3

filaments

Question 4

The filament in an x-ray tube is about _____ cm in length.

A) 1-2
B) 3-4
C) 8-10
D) 10-20

Question 5

When electrons bombard the target, ____% of their kinetic energy is converted to heat.

A) 10
B) 25
C) 50
D) 99

Question 6

The rotating anode is turned by a ____________.

A) thermal cushion
B) rotating belt
C) magnetic field
D) mechanical pulley

Question 7

Tube failure can occur from _______________.

A) extrafocal radiation
B) short exposure times
C) high kVp techniques
D) long exposure times

Question 8

The external structure of the x-ray tube includes the support structure, the protective housing, and the ___________.

A) anode
B) cathode
C) glass envelope
D) focusing cup

Question 9

The most widely used support structure for the x-ray tube is the ______________.

A) C-arm
B) floor-to-ceiling mount
C) ceiling support system
D) floor support system

Question 10

As an x-ray tube ages, the inside can become coated with tungsten, which can cause _____ in the tube.

A) convection
B) anode pitting
C) off-focus radiation
D) arcing

Question 11

What is the formula for heat units for a 3-phase, 6-pulse x-ray machine?

A) kVp × mA × seconds
B) 1.35 × kVp × mA × seconds
C) 1.41× kVp × mA × seconds
D) 1.66 × kVp × mA × seconds

Question 12

Each tube has its own tube rating chart to show __________________.

A) housing cooling times
B) anode cooling times
C) maximum exposure times
D) maximum patient doses

Question 13

Thermionic emission at the filament creates a __________.

A) space charge
B) grid control
C) line focus
D) heel effect

Question 14

The negative side of the x-ray tube holds the ________.

A) filament
B) anode
C) target
D) rotor

Question 15

The ___________ is the source of radiation in the x-ray tube.

A) filament
B) focal spot
C) focusing cup
D) stator

Question 16

Because of the line focus principal, the effective focal spot size decreases with decreasing _____________.

A) target angle
B) rotor speed
C) window thickness
D) space charge

Question 17

High capacity tube rotors revolve at ______ rpm.

A) 2000
B) 3600
C) 6000
D) 10,000

Question 18

The x-ray intensity is lower on the anode side of the tube because of the _________.

A) line focus principle
B) heel effect
C) focusing cup
D) filament length

Question 19

The cathode side of the tube should be directed toward the _____ part of the patient.

A) upper
B) lower
C) thicker
D) thinner

Question 20

The target of the rotating anode is usually coated with a ___________ alloy.

A) molybdenum
B) graphite
C) tungsten
D) copper

Question 21

The heel effect is caused by the ___________.

A) stator windings
B) anode angle
C) exposure times
D) induction motor

Question 22

Extrafocal or off-focus radiation is produced from ____________.

A) overheated anodes
B) scattered x-rays
C) rebounding electrons
D) dual focus cathodes

Question 23

The effective focal spot size is _____________ the actual focal spot size.

A) equal to
B) larger than
C) equal to or larger than
D) smaller than

Question 24

The _______ is/are outside the glass envelope.

A) stators
B) rotor
C) focal spot
D) filaments

Question 25

Localized pitting or cracking on the anode can occur from _____________.

A) filament vaporization
B) a single excessive exposure
C) long exposure times
D) high kVp and low mA