Definitions Flashcards
Percent depth dose
the ratio of dose at depth in tissue to the dose at electronic equilibrium on the beam axis. The ratio of dose at Dmax to dose at a certain depth in tissue.
Hypertension
a dizzy feeling associated with sitting or standing after a prolonged period of bed rest
Usage factor
the fraction of TIME in a treatment day in which a beam will be pointed at a particular barrier
Workload
the OUTPUT of the linac in a day
Occupancy factor
the fraction of time in a day a person will be OCCUPYING a space behind a particular barrier
Dose profile
a representation of the dose in an irradiated volume, as a function of spatial position along a single line
Linear attenuation coefficient (u)
fraction of photons attenuated per unit thickness
The shape of the isodose curves depends largely on two things:
field size and flattening filters
Irradiated volume
the volume larger than the treatment volume receiving some significant dose
Tumor volume
the actual physical dimensions of the tumor, including regions of presumed occult spread
As SSD increases, the depth dose….
increases
Exposure is measured in
C/ kg
Rad is measured in
J/ kg
Stopping power
the rate of kinetic energy lost per unit path length
Compton interaction is independent from…..
atomic number. Only photon and free electron
Pair production is ____ photon interaction with the nucleus.
direct
Isodose curve
points within the patient receiving the same dose are joined together forming a curve
What is the tolerance for daily check of linac output consistency?
3%
Pancytopenia
side effect from chemo that decreases in many cellular components of the blood
Ovarian cancer signs are (3):
abdominal bloating, nausea, constipation. NOT VAGINAL BLEEDING
- Early stage ovarian is treated with:
- Late stage ovarian is treated with:
- Surgery and then chemo
- EBRT
Early endometrial cancer sign is
abnormal vaginal bleeding
Cisplatin can cause what loss?
Hearing
Half-value thickness
is the thickness of material that reduces beam intensity to half its original value
What factor controls the contrast of an image?
Window width
What factor controls the brightness of an image?
window level
Linear Energy Transfer
rate that energy is deposited as it travels through matter
- What is Oxygen Enhancement Ratio?
- What is the formula?
- compares the response of the cells to radiation with and without the presence of oxygen
- Anoxic/ oxic
