Mosby Chp. 5 Protection

Three tenth value layers (TVL) reduce transmission to: -10% -30% -0.1% -0.3%

-0.1%

A monthly radiation exposure report says an employee received 0.5 Sv. If the source of exposure were determined to be gamma radiation, the translation to absorbed dose would be: -0.5 Sv = 0.5 Gy -0.5 Sv = 0.5 cGy -0.5 Sv = 10 cGy -0.5 Sv = 100 Gy

-0.5 Sv = 0.5 Gy

It is recommended that radiation exposure to the fetus should not exceed _________ for the entire gestation period. -0.1 rem -0.5 rem -1.5 rem -3.0 rem

-0.5 rem

According to the current recommendations, the guidance levels for cumulative exposures for a 30 year-old occupational worker with 3 years experience is: -600 mSv -300 mSv -330 mSv -50 mSv

-300 mSv (10 mSv x age)

What quantity is measured directly by the TLD? -Exposure -Absorbed dose -Activity -Lag time

-Absorbed dose

Long forceps are required for direct handling of radioactive sources so that: -Exposure time to the handler's hands is decreased -Exposure time to the handler's hands is increased -Amount of exposure to the handler's hands is decreased -Amount of exposure to the handler's hands is increased

-Amount of exposure to the handler's hands is decreased

The radioactive source inventory room should have a sign that reads: -Caution Radioactive Material -Caution Radiation Area -Caution High Radiation Area -Grave Danger-High Radiation Area

-Caution Radioactive Material

Any container in which radionuclides are transported, stored, or used must have a label saying: -Caution-Breakable container -Caution-High radiation area -Caution-Radioactive Material -Grave danger-High radiation area

-Caution-Radioactive Material

The two main types of background radiation are: -Natural and man-made -Cosmic and terrestrial -Confluent and regressive -Internal and external

-Cosmic and terrestrial

Which of the following devices is not normally used to monitor occupational exposure? -Film badge -TLD -Cutie pie -Pocket dosimeter

-Cutie pie

All of the following are advantages of the film badge personnel monitor except: -Provides permanent record -Exposure to interpretation delay -Measure dose over large body area -Radiation type can be determined

-Exposure to interpretation delay

The radiation detection device heplful in finding a lost radioactive source would be a/n: -Ion chamber -Geiger-Muller counter -TLD -Neutron counter

-Geiger-Muller counter

The workload describes: -How much the primary beam is in use -The fraction of the workload in which a barrier is irradiated -The fraction of time during which an area is occupied -Energy of the beam in use

-How much the primary beam is in use

Internal radiation exposure comes from radioactive materials always present in our bodies such as: -Xenon-131 -Technetium-99 -Hydrogen-3 -Boron-12

-Hydrogen-3

When a radiation worker is away from work, it is best to store his personnel monitoring film badge: -In a safe place away from the source of radiation -In a locker inside the linear accelerator vault -Ina drawer at the linear accelerator -In the car for quick and easy access

-In a safe place away from the source of radiation

HDR brachytherapy procedures should be performed in: -A private surgical suite -In a private hospital room -In a patient examination room -In a shielded vault

-In a shielded vault

Following discharge of a patient who received LDR, a room survey should be conducted to: -Ensure patient care staff members have not been exposed -Make sure the former patient's roommate has not been exposed -Make sure that the survey meter has maintained a suitable charge between the procedure and patient discharge -Make sure that there are no remaining radioactive sources in the room

-Make sure that there are no remaining radioactive sources in the room

Radioactive sources should be transported around the treatment facility in: -Sterile bags -Biohazard bags -Shielded containers -Sterile boxes

-Shielded containers

Which of the following was used first to measure radiation exposure and set limits: -Skin erythema dose -Tolerance dose -MPD -Dose limits

-Skin erythema dose

Patients undergoing thyroid ablation with I-131 should not be released to leave the facility until: -2 hours have past since the swallow -2 days have past since the swallow -Survey meter readings reach less than 5 mrem/hr at 1m -Survey meter readings reach 0 mrem/hr at 1m

-Survey meter readings reach less than 5 mrem/hr at 1m (or activity is 30m Ci)

The exposure from cosmic rays at sea level is lower than the exposure in Denver because? -The earth's magnetic field varies -The temp is higher at sea level -The altitude is higher in Denver -There is more atmosphere to shield the individuals who live in Denver

-The altitude is higher in Denver

Exposure from terrestrial radiation varies according to: -The thickness of the atmosphere -The magnetic field distribution of the earth -The number of diagnostic x-rays received -The composition of soil or rock in nearby areas

-The composition of soil or rock in nearby areas

According to the current recommendations, which of the following will have the highest annual dose limit? -The lens of the eye -The hands of a member of the general public - The embryo/fetus -The hands of a pregnant therapist

-The hands of a pregnant therapist

Nursing and other patient care staff caring for an admitted patient undergoing low dose radiation (LDR) brachytherapy should: -Wear a gown and gloves to prevent radiation spills -Wear a face mask to prevent inhalation of radioactive material -Wear goggles to prevent splashes of radioactive fluids to the eyes -Use standard precautions and perform duties as quickly as possible

-Use standard precautions and perform duties as quickly as possible

The term quality factor (Q): -Varies with different types of radiation -Varies with different types of tissue -Varies as a function of age and gender -Is measured in rem

-Varies with different types of radiation (AKA the radiation weighting factor, parallels the linear energy transfer of the radiation type. Radiation with high LET have higher quality factors)

The shielding around stored radioisotopes must be adequate to reduce radiation levels to: -less than 2 mrem/hr at 1m -less than 5 mrem/hr at 1m -less than 5 mSv/hr at 1 m -less than 5 mrem/hr at 1m

-less than 2 mrem/hr at 1m

The half value layer for a 6 MV beam is 32 mm of lead. The linear attenuation coefficient would be

0.0216

The half value layer for a 6 MV beam is 22 mm of lead. Its attenuation coefficient is __________

0.0315

The half value layer for cobalt is 11 mm lead. What is the linear attenuation coefficient? How much lead would reduce this cobalt beam to 3% transmission?

0.063 55.6mm

When film badges are used for radiation monitoring, which of the following factors may affect the accurate reading of the badge? 1. Exposure to excessive heat 2. Submersion of the badge in fluids 3. Damage to the film wrapper

1, 2, 3

The annual dose limit for occupational worker's lens is

150 mSv or 15 rem

The annual radiation dose to the lung from radon gas is estimated to be

200 mrem/year

How much concrete is required to reduce transmission to 2% of the primary beam?

43.9cm

How many half value layers reduce transmission to 2%? -2 -5 -6.5 -5.6

5.6

The annual dose limit for the occupational worker's skin is

500 mSv

The linear attenuation coefficient for a certain megavoltage beam using concrete as an absorber is 0.089cm^-1. What is the HVL?

7.8cm

Appropriate disposal of radioactive sources include: -Transfer to an authorized recipient -Incineration -Burial -All

All

An example of deterministic effect is: -Carcinogenesis -Genetic effects -Birth defects -Cataracts

Cataracts

In the construction of a new radiation therapy center, the choices for primary barriers include concrete, lead, or iron. Measure for measure I would need more __________ for adequate absorption. -Concrete -Lead -Iron

Concrete

T or F Maximum exposure rate at a specific distance from a patient following insertion of radioactive sources can be measured with TLDs.

F

The agency that regulates the use of radiation producing machines is the: -AAPM -NRC -DOT -FDA

FDA

The amount of energy absorbed in a medium is expressed in units of: -Roentgen -Coulomb/kilogram -Sievert -Gray

Gray

The organization in the US that is principally responsible for recommending radiation dose limits

NRC

The largest dose from natural background radiation comes from: -Terrestrial -Radon -Cosmic -Internal

Radon

T or F Two half value layers of a material for a given radiation would decrease radiation intensity to 25%

T

The requirement for barrier protection in walls/ceiling from primary radiation is reduced when there is a beam stopper on the treatment unit

T

The fraction of time that a radiation beam is directed at a specific barrier is termed

Use factor

The roentgen us a unit of measurement that specifies the __________ of air by x-rays or gamma radiation -excitation -ionization -absorption -attenuation

ionization

Dose equivalent is measured in units of: -roentgen -rad -sievert -curie

sievert