Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
23 Cards in this Set
- Front
- Back
|
contact therapy units |
40-50 kv used for surface lesions, skin cancer |
|
|
Superficial Therapy units |
Range of 50 - 150 kv treatment surface in contact with cone used aluminum filters to increase penetration |
|
|
Orthovoltage machines |
Range of 150 - 500 kv deep therapy machines replaced by linear accelerators |
|
|
Megavoltage machines |
Operate at 1000 kv or more Van de Graaff, betatron, and linear accelerators High dose rates compact design high reliability |
|
|
Define Penumbra |
It is the beam edge unsharpness, exemplied as scatter |
|
|
How is a Bending Magnet used? |
To change the direction of the accelerated electron beam from horizontal to vertical. Bends the beam |
|
|
xray target |
Accelerator target that generated x-rays are transmitted though to reach the patient. e.g. tungsten. |
|
|
vacuum pump |
to prevent power loss and electrical arcing caused by interactions of electrons with gas molecules |
|
|
flattening filter (proton beam) |
used to create a beam of sufficient area and uniformity |
|
|
scattering foil (electron beam) |
used to provide a uniform beam of dimensions suitable for treatment |
|
|
Monitor Ionization Chamber |
where an ionization current is produced and conducted to the control panel and displayed as monitor units |
|
|
parallel opposed fields |
180 degree images (ex ap/pa, right lateral, left lateral |
|
|
Bolus |
Acts as an extra layer of skin to bring the dose closer to the surface. ex. wet gauze, wet paper towels. It is not skin sparing.. |
|
|
3 things you cannot treat without |
Pathology report Informed Consent Signed Prescription |
|
|
Record & Verify |
Safeguard system to check parameters to ensure they match the planned treatment |
|
|
Fractionation |
is the individual treatment dose |
|
|
Protraction |
is the time period in which the dose is delivered |
|
|
When does QA take place? |
every 5th treatment |
|
|
what is the Isocenter? |
The point where all three points meet, most likely inside the body |
|
|
SSD (Source to Skin Distance) |
The distance from the source to the patients skin, it is measured by the ODI (Optical Distance Indicator. Most machines are 100cm SAD (Source to Axis Distance) |
|
|
Multi-leaf Collimators (MLCs) |
able to create field shapes w/o the use of focus blocks |
|
|
What are focus blocks made out of? |
BLT with Cheese (bismuth, lead, tin, and cadmium) |
|
|
Difference btwn electron and photon treatments? |
Electron treatments only penetrate a certain depth and die off, photon treatments penetrate all the way through. |
