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Questions and Answers
Roentgen is named after Wilhelm Conrad Roentgen, who discovered x-rays in 1895.
Roentgen is named after Wilhelm Conrad Roentgen, who discovered x-rays in 1895.
True (A)
One rad is equal to 0.1 joules per kilogram.
One rad is equal to 0.1 joules per kilogram.
False (B)
The quality factor (QF) is used for purposes of radiation protection.
The quality factor (QF) is used for purposes of radiation protection.
True (A)
The CURIE unit indicates the weight of a radioactive substance.
The CURIE unit indicates the weight of a radioactive substance.
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Relative Biological Effectiveness (RBE) is limited to use in radiobiology.
Relative Biological Effectiveness (RBE) is limited to use in radiobiology.
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One Sievert is equal to 100 rem.
One Sievert is equal to 100 rem.
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The Becquerel unit represents a radioactive decay rate of 10 disintegrations per second.
The Becquerel unit represents a radioactive decay rate of 10 disintegrations per second.
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Gamma rays are not usually used for external radiation due to their long path lengths in air.
Gamma rays are not usually used for external radiation due to their long path lengths in air.
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Internal sources of radiation can include radionuclides that emit alpha or beta rays.
Internal sources of radiation can include radionuclides that emit alpha or beta rays.
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Ionization chambers detect radiation by measuring heat production from radiation.
Ionization chambers detect radiation by measuring heat production from radiation.
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Flashcards
Roentgen (R)
Roentgen (R)
A unit of exposure to ionizing radiation, equal to 0.000258 coulombs/kilogram of air.
RAD
RAD
A unit of absorbed dose for ionizing radiation, where 1 rad = 100 ergs absorbed per gram.
REM
REM
A unit of dose equivalent in rads, modified for biological effect.
Relative Biological Effectiveness (RBE)
Relative Biological Effectiveness (RBE)
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Quality Factor (QF)
Quality Factor (QF)
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SIEVERT (Sv)
SIEVERT (Sv)
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BECQUEREL (Bq)
BECQUEREL (Bq)
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External Radiation Source
External Radiation Source
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Inverse Square Law
Inverse Square Law
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Ionization Chambers
Ionization Chambers
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Study Notes
Radiation Detection and Dosimetry
- Understanding ionizing radiation effects on biological systems requires knowing the radiation exposure amount and energy dissipation patterns.
Radiation Units
- Many radiation units exist, some commonly used include:
- Roentgen (R): A unit of exposure to ionizing radiation. It measures the amount of gamma or x-rays needed to produce a specific charge in air. 0.000258 coulombs/kilogram of air under standard conditions.
- Rad (Radiation Absorbed Dose): A unit of absorbed dose for any ionizing radiation. 1 rad = 100 ergs absorbed per gram of any substance, or 0.01 joule per kilogram. Approximately equivalent to the number of roentgens.
Other Units
- Rem (Radiation Equivalent Man): A unit of dose equivalent, numerically equal to the dose in rads multiplied by modifying factors like RBE (Relative Biological Effectiveness) or QF (Quality Factor). Designed to account for varying biological effects of different types of radiation. Used in radiation protection calculations.
- Quality Factor (QF): Another name for a linear energy transfer-dependent factor that adjusts absorbed doses to account for differing radiation effectiveness and is similar to RBE.
- Curie (Ci): A unit of activity of a radioactive nuclide equal to 3.7 x 1010 radioactive disintegrations per second. Shows the rate of radioactive material decay.
- Sievert (Sv): The SI derived unit of dose equivalent, considering biological effectiveness of different ionizing radiations; 1 Sv = 100 rem.
- Becquerel (Bq): SI unit for radioactivity, representing a rate of radioactive decay of 1 disintegration per second.
Relative Biological Effectiveness (RBE)
- A factor indicating the relative effectiveness of radiations with different linear-energy-transfer values in producing a given biological effect. Now mainly used in radiobiology and is typically experimentally determined for specific biological systems.
Dose Distribution Factor (DE)
- Used to express modification of biological effect caused by non-uniform distribution of internally deposited radionuclides.
Relationship Between Activity and Absorbed Dose
- External Sources: Sources of radiation not contained within the exposed material. Alpha and beta rays are less frequently used for external radiation due to limited range in air). Gamma and X-rays are common external sources. The inverse square law describes intensity variations with distance from the source.
- Internal Sources: Sources of contained radiation. Radionuclides emitting alpha or beta rays are used as internal emitters. Most energy is absorbed near the source (within ~1cm)
Radiation Detection and Measurement
- Methods for detecting and measuring radiation include:
- Ionization Chambers: Operate due to ionization produced by charged particles.
- Scintillation Detectors/Luminescent Dosimeters: Excitation of atoms by radiation causing luminescence.
- Chemical Reactions: Can be quantitatively related to radiation amount. Heat production can be measured calorimetrically.
- Latent Images/Photographic Film/Cloud/Bubble Chambers: Mark particle/photon passage.
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Description
This quiz focuses on the principles of radiation detection and dosimetry, including key units like Roentgen, Rad, and Rem. It aims to enhance understanding of ionizing radiation effects on biological systems through accurate measurement and absorption concepts.
