Physics Test part 6

Question 1

Reaches on ½ of preset value

Answer 1

rectifier malfunction

Question 2

Excessive Fluctuation

Answer 2

– loss of tube vacuum

Question 3

Spiking of meter

Answer 3

indicates a short circuit in the filament circuit of a blown high voltage cable and can be accompanied by smoke and/or the odor of burning rubber.

Question 4

. Filament Transformer

Answer 4

A step-down transformer to decrease voltage to the filament of the x-ray tube (4 – 12 volts).

Question 5

Rectifiers

Answer 5

Found in all equipment except for self-rectified.
They are located between the step-up transformer and the x-ray tube.

Question 6

diode, valve tube, or kenotron tube

Answer 6

Found on older single-phase units.
These are similar in construction to an x-ray tube in that they have a cathode and anode.

Question 7

Solid state

Answer 7

Found in all newer equipment.
These are made up of silicon crystals with various impurities that can make an N-type or P-type semiconductor.

Question 8

Valve Tube Transformers

Answer 8

Step-down transformers for the filaments of valve tubes and only used with valve tube rectifiers

Question 9

High Voltage Cables

Answer 9

Connects the high voltage section to the x-ray tube.

Question 10

POWER RATINGS FOR HIGH VOLTAGE SECTION

Answer 10

This measures the maximum power that this section can deliver to the x-ray tube during x-ray production during a 0.1 second exposure.

Question 11

. Fixed mA

Answer 11

A fixed mA is maintained by the circuitry during x-ray production.

Question 12

Falling Load

Answer 12

Used for all high frequency units and many 3-phase as well.
It is used whenever AEC and mAs timers are utilized.

Question 13

Advantages of falling load

Answer 13

Shorter exposure times in heavy load situations
* Simpler operation

Question 14

Disadvantages of falling load

Answer 14

Will not work with tomography
* Can shorten x-ray tube life due to higher mA.

Question 15

Shared Generators

Answer 15

Two separate exposure rooms share the same high voltage section.
Each room will have its own x-ray tube and control panel but will share a common high voltage section.

Question 16

Advantages of shared generators

Answer 16

• Lower capital cost versus buying two separate units

Question 17

Disadvantages of shared generators

Answer 17

Only one room at a time can make an exposure
* If high voltage section malfunctions, two rooms are down.

Question 18

X-ray Tube Supports

Answer 18

Must possess these characteristics in order to meet FDA guidelines:
a) Strong and sturdy – to support the weight of the x-ray tube, tube housing, and collimator.
b) Support must be counterbalanced
c) Must allow adequate range of motion in order to perform x-ray exams.
Must have SID indicator
e) Immobilization locks need to be incorporated in the support

Question 19

) Floor Mounted or Vertical Tube Stand

Answer 19

Oldest design for mounting the x-ray tube.
Advantages:
* Low Cost
* Simple installation
* High voltage cables can be relatively short and out of the way.
Disadvantages:
* Not as sturdy as other options
* Track is unhygienic
* Transverse and horizontal movements are restricted, making this option undesirable for a trauma room or for patients on carts or in wheelchairs.

Question 20

Floor to Ceiling Stand

Answer 20

A second track is mounted on the ceiling, directly above the track on the floor, making for a sturdier installation.

Question 21

Overhead or Ceiling Suspended System

Answer 21

The tracks are mounted on the ceiling only, with nothing on the floor.

Question 22

Integrated Tube Stand

Answer 22

The tube mount is integrated or part of the patient table.

Question 23

C or U Arm

Answer 23

The x-ray tube is mounted on one end of a large metal frame that is in the shape of the letter “C” or “U”.

Question 24

. Filtration

Answer 24

Material added immediately beneath the x-ray tube window to remove low energy or “soft” x-rays from the beam.

Question 25

The amount of total filtration can be expressed in two different ways:

Answer 25

Thickness of material
Measured in millimeters and is the most common method.
Half Value Layer (HVL)
The thickness of material that will reduce the intensity of the x-ray beam to ½ of its original intensity.

Question 26

. Collimator

Answer 26

This is mounted beneath the added filter and consists of a series of lead shutters at right angles to one another that move in opposing pairs.

Question 27

Patient Table

Answer 27

Place where patient is placed for most exams (except for upright, wheelchair or cart exams), and also contains the image receptor

Question 28

Upright Bucky

Answer 28

Upright Bucky