Linear Energy Transfer
What is the definition of Linear Energy Transfer?
The average (radiation) energy deposited per unit path length along the track of an ionizing particle
https://radiopaedia.org/articles/linear-energy-transfer?lang=us
what is RBE (relative biologic effectiveness)?
RBE provides a method to compare how damaging different types of radiation are, given the same dose, and it is calculated using X-rays as a reference type of radiation.
What is OER?
Refers to the ratio of radiation dose needed to achieve a specific biological effect in a low oxygen environment versus a well-oxygenated environment
Nett, B. (2025). Radiation Biology LET, RBE, OER OH MY! How Radiology Works. Retrieved March 4, 2025, from https://howradiologyworks.com/let-rbe-oer/
What is Radiosensitivity?
How susceptible cells are to damage from radiation
What is the law of Bergione and Tribondeau?
That the radiosensitivity of a biological tissue is directly proportional to the mitotic activity and inversely proportional to the degree of differentiation of its cells
Which is used in therapeutic, and which is used in diagnostic? High or Low LET
what has a higher LET (linear energy transfer) xrays or alpha particles?
Alpha particles
How is OER expressed mathematically?
OER=radiation dose in hypoxia (low oxygen)/ radiation dose in air
Nett, B. (2025). Radiation Biology LET, RBE, OER OH MY! How Radiology Works. Retrieved March 4, 2025, from https://howradiologyworks.com/let-rbe-oer/
What year was the first radiation-induced cancer first reported?
In what year was the law of Bergonie and Tribondeau made?
High or Low LET loses energy quickly and deposites it densely in a short path?
what is the reference for RBE?
True or False- low-LET radiation such as x-rays and gamma rays will have smaller OER value than higher-LET sources such as neutrons or alpha particles.
False, low-LET forms of radiation typically have a larger OER value because cells are more sensitive to these types of radiation.
Nett, B. (2025). Radiation Biology LET, RBE, OER OH MY! How Radiology Works. Retrieved March 4, 2025, from https://howradiologyworks.com/let-rbe-oer/
What are the 4 factors that radiosensitivity depends on?
Hypoxia, the ability to repair damage, cell cycle position, and growth fraction
https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/radiosensitivity
what are some factors that contribute to increased radiosensitivity?
Increased rate of cell division, low degree of specialization, higher metabolic rate, increased oxygenation, increased length of time they are actively proliferating
How does an ionization chamber measure LET?
It detects the number of ion pairs that are created along the path of a charged particles within the chambers gas volume.
true or false- even with the same radiation dose, a high LET radiation will cause more damage than a low LET?
About two-thirds of damage to cells in the human body after interacting with radiation is caused by _____.
Indirect action of free radicals
Nett, B. (2025). Radiation Biology LET, RBE, OER OH MY! How Radiology Works. Retrieved March 4, 2025, from https://howradiologyworks.com/let-rbe-oer/
What part of the body is the most radiosensitive?
Bone marrow and lymphatic tissues
https://www.env.go.jp/en/chemi/rhm/basic-info/2018/pdf/basic-1st-03-02-07.pdf
Tissue is more sensitive to radiation when irradiated in an ____ state?
Describe Track Average LET and Energy Average LET
the track average calculates the average energy deposited over a set track length, and the energy average calculates the average distance over which a set amount of energy is deposited
RBE is dependent upon what factors?
the fractionation of the radiation, dose level, end-point quantified for the damage, and the biological specimen
In well oxygenated environment it takes about 3 Gray to cause death in 50% of the cells. In a low oxygen environment, it takes about 6 Gray. What is the oxygen enhancement ratio?
OER is 2 using the equation OER=radiation dose in hypoxia/ radiation dose in the air divided 3 by 6
Nett, B. (2025). Radiation Biology LET, RBE, OER OH MY! How Radiology Works. Retrieved March 4, 2025, from https://howradiologyworks.com/let-rbe-oer/
What are the potential effects of radiation exposure on radiosensitive tissues>
High doses of radiation can lead to acute radiation syndrome (radiation sickness), cancer development, infertility, and damge to developing fetuses
https://www.floridahealth.gov/environmental-health/radon/_documents/radiation-qa.pdf
When are we our most sensitive to radiation exposure?