X-Ray Physics Lecture 1
|the propagation of energy from point to point||radiation|
|3 types of radiation|| PARTICULATE|
|in particulate radiation, ___-containing particles are propelled at high speeds determined by the ___ of each particle and the ___ of the explosive event (particle ___, ___ or ___) producing ___ rays, ___ particles, ___ particles, ___ beams, ___ beams, ___ rays...||mass; mass; energy; collision; fission; fusion; cathode; alpha; beta; neutron; proton; cosmic|
|mechanical radiation requires an ___ medium (matter) to propagate ___ from one place to another||elastic; energy|
|in EM, the transmission of energy is in the form of a ___/___ having both and electric and a magnetic component. a wave with just ___ of these components cannot exist.|
EM radiation is produced by ___ electrical currents and ___ currents.
possesses both ___-like (freq. & wavelength) and ___-like energy (energy & momentum [___]) properties
| wave/disturbance; one|
wave; particle; photon
|EM radiation composed of an electric field and a magnetic field in planes ___ to each other||perpendicular|
|EM radiation is characterized by its ___, ___, and ___. when EM waves are ordered in accordance with their freq. or wavelength, this ordered array is called the ___ ___.||frequency, wavelength, energy; ELECTROMAGNETIC SPECTRUM|
|XRs contain no ___||mass|
|XRs are electrically ___||neutral|
|XRs are ___||invisible|
|XRs travel at what speed?||light speed|
|XRs can/cannot be focused by a lens?||cannot|
|XRs are highly ___||penetrating|
|XRs travel in ___ lines in a ___ beam.||straight; divergent|
|XRs produce ___ and ___ radiation.||secondary; scatter|
|XRs cause certain substances to ___.||fluoresce|
|XRs can expose ___ ___||photographic film|
|XRs have a medically useful range of energies from about ___ keV/___ E to about ___ keV/___ E||15; low; 150; high|
|keV=?||thousand electron volts|
|XRs can convert themselves to ___ when passing through matter||heat|
|XRs can ___ matter|| ionize|
e.g., ionization, ionizing radiation
|to eject orbital electrons from atoms||ionize|
|XRs can produce ___ changes by means of induced molecular ___.||biological; alterations|
|what type of wavelength, freq., and energy level do soft XRs have?||long (SOFT); low; low (LOW PENETRATION)|
|what type of wavelength, freq., and energy level do hard XRs have?||short (HARD); high; high (HIGH PENETRATION)|
|low energy (soft) XRs have poor ___, most are ___.|
___ absorbs >6 times more of these soft XRs than ___ tissues.
to get an image, it is necessary to ___ the region with a ___ number of XRs.
___ is not penetrated well; maybe not at all if the energy is ___ enough.
if an enormous number of XRs are used, eventually the soft tissues become ___, then ___ (overexposed), but bone cannot be penetrated and remains ___.
THIS IS TERMED ___ ___.
SINCE IT TOOK A TREMENDOUS NUMBER OF XRs TO GET THIS HIGH CONTRAST IMAGE, THE DOSE OF RADIATION WAS THEREFORE ___.
| penetration; absorbed|
grey; black; white
|HIGH ENERGY (HARD) XRs:|
___ matter easily, few are absorbed.
bone absorbs only ___-___ times more of these hard XRs than soft tissues (bone & soft tissue look nearly the same).
since hard XRs are very penetrating, only a ___ number of XRs are necessary to get thorough ___.
if a large number of hard XRs are used, the whole image (bone & soft tissue) becomes ___, then ___ (overexposed), therefore, only a ___ number of hard XRs can be used.
bone and soft tissue are nearly ___ penetrated.
therefore, bone and soft tissue are similar in ___.
THIS IS TERMED ___ ___.
SINCE IT TOOK A LOW NUMBER OF XRs TO GET THIS LOW CONTRAST IMAGE, THE DOSE OF RADIATION WAS THEREFORE ___.
grey; black; small
|A HIGH CONTRAST IMAGE requires a relatively ___ dose of ___ energy XRs.||HIGH; LOW|
|A LOW CONTRAST IMAGE requires a relatively ___ dose of ___ energy XRs.||LOW; HIGH|
|intensity varies throughout beam; sharpness & resolution (focal spot varies throughout beam)...what do these properties describe?||heel effect|
|3 components of early XR tubes|| source of electrons|
means to accelerate these electrons
high Z target to be bombarded by the electrons
|Roentgen made his discovery with a ___ TUBE (not designed/optimized for XR production)||CROOKES|
|re: EARLY GAS TUBES, the source of electrons was the ___ ___ gas inside; it was difficult to get ___ XR production (mA was hard to control)||partial pressure; consistent|
|COOLIDGE TUBE (1st tube with a heated ___, termed hot ___ tube); the source of electrons was the ___ (tube evacuated to a near ___); consistent ___ resulted in consistent XR production.||filament; cathode; filament; mA|
|4 components of basic XR tube design|| 1. CATHODE ASSEMBLY (-) CHARGE|
2. ANODE ASSEMBLY (STATIONARY/ROTATING) (+) CHARGE
3. LOW VOLTAGE (FILAMENT/ELECTRON-RELEASING) CIRCUIT (mA)
4. HIGH VOLTAGE (ELECTRON ACCELERATING) CIRCUIT (kVp)
| CATHODE ASSEMBLY (-) CHARGE:|
filament (___ emission/___ Effect)
each filament sits in its own ___ focusing cup
| thermionic; Edison|
| SMALL FILAMENT produces the SMALL ___ ___ (___)|
___ or ___ mm rated focal spots
better ___ (sharper image, less focal spot ___)
can only be used with lower ___ settings
therefore produces ___ XRs, ___ XR output
| FOCAL AREA (SPOT)|
| LARGE FILAMENT produces the LARGE ___ ___ (___)|
___ or ___ mm rated focal spots
poorer ___ (___ image, more focal spot ___)
supports higher ___ settings
produces the ___ XR output for that tube
| FOCAL AREA (SPOT)|
definition; blurrier; blur
|ANODE ASSEMBLY can be either ___ or ___ and has a ___ charge||stationary; rotating; +|
|ANODE ASSEMBLY has a ___ ___ target||high Z (W)|
|stationary anode design: (stationary ___); ___ block (target) bonded to a bulky copper assembly (___ sink)||target; tungsten; heat|
| rotating anode design:|
rotating target ___ on a ___ disk
the target area now becomes a ___ target track with 100+ times (___ focal spot) and 200+ times (___ focal spot) the target area of a stationary anode design tube -- ___ hundreds of times the heat allowing hundreds of times the XR production before anode ___ occurs.
| track; tungsten|
circular; large; small; dissipates; damage
|higher ___ capacity allows the higher tube ___ (mA) which allows increased XR output allowing for ___ focal spots and/or ___ exposure times||heat; currents; smaller; shorter|
| the larger the ___ & ___ of the anode disk, the ___ the XR output, and also the more ___ the tube|
125,000 HU tube costs about $4500 (standard equipment)
400,000 HU tube costs about $8500 (extra ___ capacity/___)
|diameter; mass; higher; expensive; heat; power|
| LOW VOLTAGE (___/electron-___) CIRCUIT (mA):|
source of ___
| filament; releasing|
| HIGH VOLTAGE (electron ___) CIRCUIT (kVp):|
means to ___ the electrons
|gamma rays come from the ___; x-rays come from ___; however, the 2 end products are identical if their ___ are the same||nucleus; electrons; frequencies|
|a ___ is an imaginary particle that travels at the speed of light||photon|
|which descriptive system is used to categorize EM radiation?||ENERGY (keV)|
|dislodging an electron from an atom is termed ___||IONIZATION|
|which is not a type of EM radiation?||ALPHA PARTICLES|
|increasing the frequency of EM also increases ___||ENERGY|
|a hard XR beam consists primarily of XRs that are primarily ___ wavelength, ___ freq., and ___ energy||short; high; high|
|to LOWER the X-radiation dose to a patient, ___ the XR energy, then ___ the quantity||increase; lower|
|in XR tube, which particle is accelerated to produce XRs?||electron|
|how many filaments are present in a general purpose XR tube?||2|
|advantage of a rotating anode XR tube is?||better heat distribution; more XRs|
|be able to identify and know the significance of the components on the diagram that follows.|
|What is the following diagram an example of?|| |