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Basic Rad Units
Basic Radiation Units
Question | Answer |
---|---|
Conventional Unit of Exposure | Roentgen (R) |
SI Unit of Exposure | Coulomb/kg (C/kg) |
Conventional Unit of Absorbed Dose | rad (R x f-factor) |
SI unit of Absorbed Dose | gray (Gy) |
How many rads in 1 Gy? | 100 rads = 1Gy |
Conventional unit of Equivalent dose | rem |
SI unit of Equivalent dose | sievert (Sv) |
How many rem in 1 Sv? | 100 rem = 1Sv |
Conventional unit of radioactivity | Curie (Ci) |
SI unit of radioactivity | becquerel (Bq) |
Definition of Exposure? | Metric of ionization of air due to radiation. Only defined for xrays and gamma rays. |
Definition of Absorbed dose? | Energy deposited by radiation in a given mass of material. |
What are some qualities of the f-factor? | Varies with Z, varies with photon energy. At diagnostic levels, is >1 for bone, roughly = 1 for soft tissue, and <1 for fat. |
Definition of Equivalent dose? | Absorbed dose x radiation weighting factor. Corrects for the fact that heavy particulate radiation (protons, neutrons, alpha) are more damaging that EMR and electrons. |
Radiation weighting factor of X-rays, gamma rays, beta particles, and electron? | 1 |
Radiation weighting factor of protons? | 5 |
Radiation weighting factor of neutrons? | 5-20 (energy dependent) |
Radiation weighting factor of alpha particles and other multiple charged particles? | 20 |
Definition of Effective Dose? | equivalent dose x tissue weighting factor. Considers how sensitive given tissue is to radiation. |
What tissue has the highest tissue weighting factor? | Gonads (20) |
What number do all tissues weighting factors summed equal? | 1 |
What was the original definition of the curie? | the activity of 1g of pure radium (3.7 disintegrations/s) |
How many dps (disintegrations per second) per Bq? | 1 dps |