Flashcards in Make Up Deck (63)
1/2 of the range from crest to valley
Is the distance from one crest to another, from one valley to another, or from any point on the sine wave to the next corresponding point.
Is the number of wavelengths that pass a point of observation per second.
Allows current flow in one direction. x-ray tubes must be provided with direct current. X-rays are produced by the acceleration of electrons from the cathode to the anode.
is accomplished with diodes. A diode is an electronic device that contains two electrodes. they are made by solid-state rectifiers made of silicon.
Single Phase Power
Single phase power results in a pulsating x-ray beam. This is causes by the alternate swing in voltage from zero to maximum potential 120 times each second under full-wave rectification. The x-rays produced when the single-phase voltage waveform has a value near zero are of little diagnostic value because of their low energy; such xrays have low penetrability.
Three Phase Power
Multiple voltage wave forms are superimposed on one another, resulting in a waveform that maintains a nearly constant high voltage. There are 6 pulses per 1/60s compared with the two pulses characteristic of single phase power.
High frequency Generator
High frequency generators produce a nearly constant potential voltage waveform, improving image quality at lower patient radiation dose.
HU=kVp x mAxS
3 phase, 6 pulse
HU=kVp x mAxs =1.35....35%
3 phase, 12 pulse
HU=kVp x mAxs=1.41...41%
To see significant increase in density
increase mAs 30%
To see Double density: must
double mAs, or increase kVp by 15%
Intervertebral Foramina 90 degrees Lateral (right or left)
Zygaphophyseal Joints 45 degrees obliques
Intervertebral Foramina 45 degrees oblique
CR 15 degrees cephalad--upside visualized
RPO-- left foramina
CR 15 degrees caudad--downside visualized
LAO ---left foramina
Intervetebral Foramina 90 degrees (right or left lateral)
Zygaphphyseal joint 70 degrees oblique
LPO ---right zygopophyseal
Bodies center of gravity
Radiographic Rating Chart
is most important indicates safe/unsafe techniques
x-axis: exposure time
Below mA line is safe
Anode cooling chart
Shows how long to wait to make more exposures after anode has rached max capacity (HU)s
x-axis: time (minutes)
curve line: cooling curve
XR Emission Spectrum
x-axis: energy (keV) quality
inherent filtration 0.5mm
added filtration 1.0mm
CR uses IP:
1. Protective layer
2. Phosphor layer---BFH coated with Europium (PSP) photostimulable phosphore (active layer)
3. light reflective---sends light forward (some detail lost)
4. conductive ---absorbs static electricity.
5. support----semi-rigid, gives IP strength
6. light shielding
7. backing---protects back
Solid State lasers
less diameter----better spatial resolution
Blue light is emitted
Number of grid lines per cm/m
typically 150 + lines/inch
Fuji: S# target 200-400 (inverse) high S# means underexposed
Kodak/Carestream: Ei Target 2000 (direct)
Agfa: log mean target =2.2 (direct)
in DR is pixel limited
uses flat panel direct capture detector (then temporary stored in TFT's or thin silm transistors)
Indirect conversion System
X-ray absorbed by cesium iodide --light
light interacts with Amorphous silicon