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Nonlinear Threshold Dose-Response. Radiation Dose-Response Relationship. Also known as the dose response curves, which is graphically determined by a curve that diagrams the observed effects of radiation exposure in relation to the dose of the radiation given.
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Radiation Dose-Response Relationship • Also known as the dose response curves, which is graphically determined by a curve that diagrams the observed effects of radiation exposure in relation to the dose of the radiation given.
Dose-Response curves different in two ways: • They can either be linear or non linear linear (straight line) nonlinear (curved to some degree) • They can also be either threshold or nonthreshold
Nonlinear • Nonlinearcan be described as a relationship or function that is not exactly proportional. • For Example: An observed response that is not directly proportional to the dose. • Doubling the dose of radiation, does not double the response.
Threshold • Threshold is the point at which something begins or changes. (Starting Point) • In this case, it assumes that there is a radiation level reached below which no effects can be observed.
Nonlinear Dose-Response • Also known as the Sigmoid Dose Response Curve. • Sigmoid meaning S-shaped (curve) • This curve is mainly applied to the high dose effects observed in radiotherapy. • There is usually a Threshold below which no visible effects happen.
Sigmoid Dose Response • High-dose cellular response can be recognized through the use of Nonlinear threshold dose response. (Sigmoid) • For example: High-dose chemotherapies
Sigmoid Dose-Response Curve Response to radiation received ---------> Radiation dose received ------->
Questions True or False • The dose-response curve is generally determined by a graph that diagrams the curves and observes the effects of radiation exposure in relation to the dose. • True • What are the two ways the curve can be described? • Linear and Nonlinear
True or False • Nonlinear is an observed response that is not directly proportional to the dose. • True • Threshold is the point which something ends, and effects can be observed. • False
What is Non-linear dose response also referred to as? • The Sigmoid dose response Curve • Sigmoid means: • S-shaped curve The End