Linear Energy Transfer (LET)
different biological responses
Comparing radiation types is important because different types of radiation = ___________ ___________ ___________.
radionuclide
High LET is at greatest concern during internal contamination such as when a _____________ is implanted, ingested, injected, or inhaled.
low
High Let has _____ penetrating power, lose energy rapidly and have direct action on DNA.
linear
Ionizing energy is deposited/ transferred in a __________ manner as it travels thru tissue.
damage potential
LET allows us to compart the ________ ________ of different types of radiation.
mass and charge
LET depends largely on the ________ ___ ______ of the radiation.
rate
LET meausres the ______ at which energy (IR) is transferred to soft tissue per unit traveled.
3 keV
LET of diagnostic x-rays is ______ (relatively low LET).
weighting factor
Linear energy transfer determines the radiation _________ _________ Wr (Q-quality factor) of each type of radiation.
radiation quality
Linear energy transfer is a way to express _________ _________.
kiloelectron volt (keV)
Linear energy transfer is expressed in units of _________ ______ of energy transferred per micrometer of soft tissue.
the speed of light
Low LET has no mass or charge. It travels at _____ _________ ___ __________.
randomly
Low LET is highly penetrating and interacts ________. It loses energy slowly.
indirect
Rapid travel doesnt allow fro much energy to be deposited (low energy transfer) in tissue; mainly causes _________ damage (sublethal, repairable?) involving free radicals.
direct
Slow travel allows for more energy to be deposited (high energy transfer) to tissue, cause of _________ damage (lethal, irreparable) to DNA.
alpha particles
Some IR has mass and charge, such as; ______ ______.
photons
Some IR has no mass or charge, such as; x-rays, gamma rays, are just ________ (bundles of electromagnetic energy).
quality
The _________ of the radiation has an effect on the extent or degree of the biologic response.
LET
___=average energy deposited/transferred per unit length of track (unit of distance) in tissue.
high LET
____ _______ travels through on a few cells, but deposits all of its energy directly into these few cells.
low LET
_______ ________ travels through 10000s of cells and may or may not interact.
mass
_________- weight; identifiable form or quantity of material.
x-rays and gamma rays
low LET radiation:
increases
As LET increases, radiation's ability to cause biological response ___________.
particulate radiation
Example of High LET radiation:
frequently
High LET = ionizations occur __________.
slowly
High LET has a large mass and charge, they travel ________, and lose energy quickly.