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Radiation Protection
Radiation Protection for Radiation Therapy
Radiation with sufficient energy to separate an electron from its atom | Ionizing Radiation |
True or False: Alpha Particles have a high LET radiation | True |
True of False: Photons have no mass and no charge | True |
What are the three types of natural background radiation? | Cosmic rays, Terrestrial radiation, and Internal exposure |
Medical x-rays, nuclear medicine procedures, and consumer products such as televisions and tobacco products, are all examples of what? | Man-made sources of radiation |
The amount of ionization produced by photons in air per unit mass of air. | Exposure |
The SI unit for exposure | C/kg |
True or False: Exposure is only defined for ionization produced by photons interacting with air | True |
The energy absorbed per unit mass of any material | Absorbed dose |
The SI unit for exposure | Gray (Gy) |
True or False: Alpha particles and neutrons have a greater biological effect than x-rays. | True |
The SI unit for dose equivalent | Sievert (Sv) |
The quality factor for X-rays | 1 |
The quality factor for alpha particles | 20 |
The rate at which a radioactive isotope undergoes nuclear decay | Activity |
The two types of Gas-Filled Detectors | Ionization Chambers and Geiger-Muller (G-M) detectors. |
True or False: G-M counters are very sensitive, therefore, they are appropriate for detecting low levels of radiation or radioactive contamination | True |
The amount of blackness on an x-ray film; related to the amount of radiation received by the film | Optical Density |
The NRC stands for | Nuclear Regulatory Commission |
Oversees the use of isotopes produced in nuclear reactors | The NRC |
Transportation of radioactive materials is the concerned of what two agencies? | Department of Transportation (DOT) and the NRC |
LD 50/30 stands for | The lethal dose of 50% of the population within 30 days |
Erythema, epilation, cataract formation, and infertility are all examples of what type of effect? | Nonstochastic effects |
Cancer induction, genetic effects, and embryologic and teratogenic effects are all examples of what type of effect? | Stochastic effects |
ALARA stands for | As Low As Reasonably Achievable |
A measure of the genetic risk to a population as a whole from exposure to ionizing radiation of some or all members of that population | Genetically significant dose (GSD) |
The effective dose equivalent, which is the limit for stochastic effects, is | 50 mSv |
The nonstochastic limits for the lens of the eye are | 150 mSv |
The total dose equivalent for an embryo or a fetus is | 5 mSv |
What are the four types of personnel monitoring devices? | Film badge dosimeter, TLD, optically stimulated luminescence (OSL) dosimeter, and pocket ionization chamber (pocket dosimeter) |
True or False: TLDs are used in ring and wrist badges. | True |
True or False: In a TLD, the amount of light emitted is proportional to the amount of radiation absorbed. | True |
Workload | How many patients will be treated per week and how much radiation will be given to each one |
Primary Beam Use Factor | The fraction of time of use the beam will be aimed at the wall |
Occupancy Factor | The fraction of time the area will be occupied |
Factors for shielding requirements | Workload of the machine, Primary Beam Use Factor for each wall, Occupancy Factor for each area adjacent to the therapy room, Distance from the source of radiation to the occupied area, and Effective Dose Equivalent limit for the occupied area. |
Therapy rooms can exceed 1 mSv in 1 hour. Therefore, the room must have a warning sign that says what? | “Caution, High Radiation Area” |
Beam-on light indicators are required on what three areas? | On the control panel, at the entrance door, and on the treatment unit. |
Entrance doors to therapy rooms must be equipped with a(n) ______ that will shut off the machine if the door is opened during treatment. | Interlock |
Regulations require both _____ and ______ communication between the therapist and patient during treatment. | Visual and Aural |
What radiation warning signs are needed for LDR patients? | Caution signs should be on the entrance door, and the patient’s wrist, bed and chart. |
Patients with LDR procedures are hospitalized for how long? | 24 to 72 hours |
For LDR brachytherapy, the position of the patient’s bed should be | So that the patient in the adjoining room will not receive an excess of effective dose equivalent limit for the general public; usually bed placed by a wall adjacent to a stairway or other little occupied area. |
Develops standards of protection for users of x-rays and other ionizing radiation. | International Commission on Radiological Protections (ICRP). |
This national group makes recommendations for protection against exposure | The National Council on Radiation Protection and Measurements (NCRP) |
The formula: E = Wt (Wr) x absorbed dose, is to calculate what? | Effective Equivalent Dose |
Scatter or leakage radiation, coming from source housing or after interacting with the patient requires what type of barrier? | Secondary barrier |
The formula to calculate the half value layer is | HVL = 0.693/M ; M: linear attenuation coefficient |
True or False: Gieger counters can only detect the presence of radiation in the area, but cannot quantify the amount of dose in the area. | True |
True or False: In a TLD, the amount of light emitted is proportional to the amount of radiation absorbed. | True |
True or False: A film badge can discriminate between different types and energies of radiation | True |
The three time-honored methods of radiation protection are | Time, Distance, and Shielding |