Image Production 4.2

Question 1

Cassetteless digital systems have a fixed spatial resolution determined by

Answer 1

(TFT) Thin film transisitor

(DEL) detector element size. Size is fixed so max detail is defined by physical size of the individual elements

Question 2

Cassetteless system

Answer 2

direct or indirect digital system; where no cassette/IP is used.

Question 3

CR

Answer 3

uses IP containing PSP

Question 4

Laser divergence

Answer 4

negative factor that occurs in CR readers

Question 5

Focal spot size

Answer 5

appropriate for anatomical part being imaged is important to render optimal image resolution

Question 6

Proximity of the phosphor screen crystals

Answer 6

refers to conventional film-screen radiography

Question 7

If 30/23/15cm TRIFOCUS IMAGE INTENSIFER is operated in the 15-cm mode, the fluoroscopic image will be magnified by a factor of?

Answer 7

The degree of magnification (MF) is found by dividing the fullsize input diameter by 30 cm by the selected input diameter (15 cm) MF = 30 cm/15 cm =2.0
If image intensifer was operated in the 23-cm mode, the MF would be 30/23=1.3. If the II was operated in the 30-cm mode, the MF would be 30/30=1.0

Question 8

Device used to change ac to unidirectional current is

Answer 8

Solid-state diode; AKA rectifiers. Md of semiconductive materials suchas silicon, selenium, germanium that conduct electricity in only one direction.

Question 9

xray circuit devices suchas transformer/autotransformer

Answer 9

operates on AC

Question 10

xray tube

Answer 10

operates on unidirectional. So current RECTIFIED before it gets to tube.

Question 11

Process of full wave rectification

Answer 11

changes neg halfcycle to useful positicleve halfcy

Question 12

XR circuit rectification system

Answer 12

located between secondary coil of the high-voltage transformer and the XR tube

Question 13

A series of rectifiers placed between transformer and XR tube

Answer 13

function to change AC to more useful DC

Question 14

During CR imaging, the latent image present on PSP changed to a digital signal by the

Answer 14

ADC analog to digital converter

Question 15

Exposed CR cassette is placed into CR scanner/reader

Answer 15

where PSP is removed automatically

Question 16

The latent image appears as the PSP is scanned

Answer 16

by helium neon laser to obtain pixel data

Question 17

PSL photostimulated luminescence

Answer 17

As the plate is scanned in the CR reader, it releases a violet light

Question 18

The analog image

Answer 18

the luminescent light is converted to electrical energy

Question 19

The electrical energy is sent to ADC

Answer 19

where it is digitized and becomes the digital image that is displayed eventually on highres monitor or printed by laser printer

Question 20

The secondary side of autotransformer feautres 2 multiple channel selection switched, to choose the number of coils that will supply voltage to the primary side of the high voltage transformer. Choosing more or less coils exploits

Answer 20

The transformer law

Question 21

The KVp selector

Answer 21

is an array of multiple connection points to the autotransformer coils on the theoretical secondary side of the device

Question 22

autotransformer

Answer 22

operates on self-induction; having one column of coided wire tha functions as bothe the primary and secondary side.

Question 23

autotransformer

Answer 23

by changing the number of coils selected, the technologist is setting the value for Ns, the number of turns of the secondary side of the transformer.

Question 24

Transformer Law

Answer 24

Vs/Vp = Ns/Np

By changing Ns, the tech is indirectly changing secondary voltage.

Question 25

mA selector

Answer 25

Ohm’s Law

Question 26

Focusing cup

Answer 26

Coulomb’s Law

Question 27

To explit E=mc2, the mass to energy conversion formula

Answer 27

need PET scanner, nuclear power plant, nuclear weapon

Question 28

Combos that offer the greatest heat-loading capability

Answer 28

The smaller the focal spot size, the more limited the anode is with respect to the quantity of heat it can safely accept

Question 29

Combos for anode include t

Answer 29

target angle and focal spot size
12-degree target angle, 1.2-mm actual focal spot

Note: a steep target angle increases the heel effect

Question 30

Mask image

Answer 30

Digital image subtraction. Pixel values are electronically subtracted fr pixel values

Question 31

Ghost/phantom image

Answer 31

an image artifact; the appearance of ghost images can be seen when CR image plates are incompletely erased or IP has not been used for 24 hrs

Question 32

Moire image/artifact

Answer 32

if a grid has a frequency that approx the CR scan frequency and the grid strips are orientated in the same direction as the scan.

Question 33

Latent image

Answer 33

is image exsists on film prior to chemical processing.

Question 34

In Digital Fluoroscopy what is eliminated

Answer 34

“overheads” -images sent thru ADC allows images post-processing which eliminates nd for overheads

Question 35

what is the smallest particle of an element that retains the characteristics of the element

Answer 35

“atom” - An element is md up of 1 kind of atom.

The atom may be broken down into subatomic particles but not have characterisitics of the element

Question 36

xrays travel as bundles of energy called

Answer 36

photons or quanta

Question 37

Atomic mass

Answer 37

is the number of protons and neutrons in the nucleus represented by the letter “A”

Question 38

When a predetermined level of ionization is reached in the ionization chamber, what does the machine do

Answer 38

Exposure is terminated.

AEC is very dependant on KVP

Question 39

What type of XR machine uses a continually decreasing mA for the shortest times possible

Answer 39

“Falling load generator”

Allowing for shortest exposure time mks use of max heat storage capacity at every mA.

Question 40

What type of current is req’d for proper operation of the XR tube

Answer 40

“unidirectional/direct current/DC”

uses rectifer to change AC to DC