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RT 140 Ch.6
Radiation Protection
Question | Answer |
---|---|
Law of Bergonie and Tribondeau | 1. Stem cells are radiosensitive. 2. Younger tissues and organs are more radiosensitive 3. High Metabolic activity - radiosensitivity is high. 4. Increase proliferation rate for cells and the growth rate for tissues, the radiosensitivity also increas |
Radiation Dose Response Relationship | Described as a mathematical relationship between different radiation doses and the magnitude of the observed response. |
what are 2 important applications in radiology for the Radiation Dose Response Relationship? | 1. Experimentally determined relationships can be used to design therapeutic treatment routines 2. Radiobiologic studies have been designed to provide information on the effects of low-dose irradiation. |
The studies and the dose-response relationships obtained are the basis for? | Radiation control |
Every radiation dose-response has what two characteristics? | 1. It is either linear or nonlinear 2. It is either threshold or non-threshold |
Which model is more conservative, and is used to establish dose limits for occupational exposure? | Linear Non Threshold |
Which model implies that a biologic response to ionizing radiation is proportional to Dose? | Linear Non Threshold |
Which model estimates the risk associated with low level radiation (BEIR)? | Linear Quadratic Model |
Which is a more accurate model at reflecting somatic and genetic effects at Low Dose levels from Low LET radiation? | Linear Quadratic Model |
Threshold (Non-Stochastic) effects | Point in which a respsonse or reaction to increasing stimulation first occurs |
Non threshold (Stochastic) effects | Any radiation dose will produce an effect * “No radiation Dose is believed to be safe” |
Which effect is an ALL or NONE phenomenon. | Non threshold (Stochastic) effects |
What has a deterministic effect? | Non-Stochastic (Threshold) |
What stage is characterized by nausea, vomiting, and diarrhea (N-V-D)? | Prodromal stage |
What occurs within minutes to hours of exposure and continues for up to one or two days? | Prodromal stage |
What dose must be greater than 100 cGy before the onset of syndrome? | Prodromal stage |
What subject is free of visible effects there is a sense of well being? | Latent stage |
What duration is dose related 100 to 500 cGy (weeks), greater than 5000 cGy (hours)? | Latent stage |
What stage is either recovery or death from the radiation injures? | Manifest illness stage |
When does Bone Marrow Syndrome occur? | Between 1 and 10 Gy * Death occurring at 2 Gy |
LD 50/60 occurs at what dose? | 3 to 4 Gy |
When does GI syndrome occur? | Between 10 and 100 Gy * Symptoms occur after 6 Gy |
What is the LD for GI Syndrom? | 6 to 10Gy |
When does CNS syndrome occur? | Greater than 50 Gy * Some occurring after 20Gy |