SP3:Radiation Safety

Question 1

Which of the following bodies regulates transportation of radiopharmaceuticals?
(a)NRC

(b) DOT
(c) TJC
(d) FDA

Answer 1

(b) The Department of Transportation is the controlling authority for the packaging and transport of all hazardous materials.

Question 2

Which of the following bodies regulates the use of investigational pharmaceuticals?
(a)NRC

(b) DOT
(c) IRB
(d) FDA

Answer 2

(d) All the use of investigational pharmaceuticals is regulated by the Food and Drug Administration.

Question 3

In the event of a spill of 99mTc to clothes, one should immediately:
(a)Enter a shower fully clothed.

(b) Remove and store the clothes until they decay to background.
(c) Wash the clothes in hot water and then survey them to determine remaining activity.
(d) Remove and destroy the clothing.

Answer 3

(b) The first priority in event of a spill is to contain the contamination, i.e., to keep it from being spread. In this case, that would be accomplished by removing the clothing and storing it until the activity has decayed to background level.

Question 4

If a radiopharmaceutical is spilled on the floor, the first priority is to:
(a)Contact the Radiation Safety Officer.

(b) Pour a chelating solution over the area of the spill.
(c) Cover the area with absorbent paper and restrict access around it
(d) Call the housekeeping department to arrange for cleaning.

Answer 4

(c) The contamination must be contained as a first priority. Using a chelating agent may change the chemical structure of the substance spilled but will not affect the radioactivity of it. The Radiation Safety Officer should be notified, but first access to the area of the spill must be restricted.

Question 5

The inverse square law, in words, says:
(a)If you double the distance from the source of activity, you reduce exposure to 25% of the original intensity.

(b) If you halve the distance from the source of activity, you decrease exposure to 25% of the original intensity.
(c) If you halve the distance from the source of activity, you decrease exposure to one-fourth of the original intensity.

Answer 5

(a) By doubling the distance, the intensity is reduced to one-quarter of the original activity, as shown in the formula below, where I1 is original intensity, I2 is the new intensity, d1 is the original distance from the source, and d2 is the new distance form the source.

I1 / I2 = (d2)^2 / (d1)^2

This can be rearranged to (I1)(D1)^2 = (I2)(D2)^2 for easy solving.

Question 6

What is the best way to decrease the radioactive dose to visitors if a patient is surveyed to emit 3 mR/h at bedside?
(a)Have the patient wear lead aprons.

(b) Keep the patient well hydrated and encourage frequent voiding.
(c) Have the visitor sit or stand as far as possible from bedside.
(d) Have the visitor wear lead shielding.

Answer 6

(c) The best and simplest way to decrease exposure to a visitor would be to increase the distance form the patient. If the exposure rate is 3 mrem/h at bedside, we can estimate 1 ft. from the patient and we move the visitor to 2 ft. from the patient, the exposure rate at the new distance would be 0.75 merm/h. (The equation in solution to question 5 of this chapter is rearranged to read (I1)(d1)^2 = (I2)(d2)^2 and solved for the new intensity.)

Question 7

Which of the following isotopes would be effectively shielded by a plastic syringe?
(a)67Ga

(b) 89Sr
(c) 99mTc
(d) 81mKr
(e) 133Xe

Answer 7

(b) Beta emitters can be effectively shielded by a few millimeters of plastic or Lucite. If shielded with lead, bremsstrahlung radiation will be produced from the slowing beta particles.

Question 8

What is the NRC annual dose limit allowed to the lens of the eye?
(a)1.5 mrem

(b) 15 rem
(c) 50 rem
(d) 5 rem

Answer 8

(b) The NRC annual dose limit permitted to the lens of the eye is 15 rem. The skin of extremities is permitted to 50 rem, and the whole body total effective dose equivalent is limited to 5 rem (10 CFR 20.1201)

Question 9

Which of the following should be used when administering an intravenous pharmaceutical to a patient?
(a)Lead syringe shield

(b) Leaded eyeglasses
(c) Gloves
(d) (a) and (b) only

Answer 9

(c) Gloves should be used when administering any pharmaceutical. Had the question stated a radiopharmaceutical, a syringe shield would also be needed, unless the radiopharmaceutical was a beta emitter.

Question 10

Which of the following is the most effective means of measuring low levels of removable radiation?
(a)By performing an area survey

(b) By performing a wipe test
(c) With a pocket dosimeter
(d) With a TLD

Answer 10

(b) Wipe tests are used to detect removable contamination from surfaces such as packages, floors and counters and are achieved by wiping the area in question with a dry wipe and then counting the wipes along with a background sample in a well counter.

Question 11

What is the dose rate limit at the package surface for a shipment of radioactive material bearing a Yellow-III label?
(a)200 mR/h

(b) 50 mR/h
(c) 200 rads
(d) 200 mrem

Answer 11

(a) DOT labeling categories are as follows: Radioactive White I, limited to packages with a dose rate of 0.5 mrem/h or less at the surface; Radioactive Yellow II, limited to packages with a dose rate of greater than 0.5 mrem/h but less than 50 mrem/h at the surface; Radioactive Yellow III, for packages with a dose rate of greater than 50 mrem/h but less than 200 mrem/h at the surface. Choice (d) is incorrect because it does not give a dose rate measured in mrem/h.

Question 12

Which of the following measures absorbed doses?
(a)mCi

(b) Becquerel
(c) Gray

Answer 12

(c) The gray (Gy) is an international unit (SI) measuring absorbed radiation dose and is equal to 100 rad. The millicurie (mCi) and the Becquerel (Bq) measure radioactivity according to disintegrations per time. The Becquerel is equal to 1 disintegration per second (dps), and the mCi is equal to 37 MBq.

Question 13

If the dose rate at 3 m from a radioactive source is 100 mrem/h, what will the dose rate be at 6 m?
(a)25 mR/h

(b) 50 mR/h
(c) 75 mR/h
(d) 12.5 mR/h

Answer 13

(a) This can be solved using the inverse square law ((I1)(D1)^2 = (I2)(D2)^2) to find 25 mrem/h. Or one can recognize that the distance has been doubled, so the intensity is reduced to one-fourth of the original

Question 14

The philosophy of the ALARA program is to keep the radiation dose:
(a)As low as recently authorized

(b) As long as reasonably attained
(c) As long as reasonably acceptable
(d) As low as reasonably achievable

Answer 14

(d) ALARA is the mnemonic for the NRC’s radiation protection philosophy that one should keep radiation exposure as low as reasonably achievable.

Question 15

All of the following are critical factors in keeping radiation exposure to a minimum except:
(a)Time spent near the radioactive source

(b) Geometry of the container holding the source of radiation
(c) Distance from the source of radiation
(d) Shielding of the radioactive source

Answer 15

(b) Time, distance, and shielding are the most important factors to consider when attempting to reduce exposure to radiation.

Question 16

Gaseous radiopharmaceuticals may only be used in rooms that:
(a)Have at least one window

(b) Contain an oxygen supply
(c) Are at a positive pressure compared to surrounding rooms
(d) Are at a negative pressure compared to surrounding rooms

Answer 16

(d) Airborne radiation, such as aerosols or gases, should be administered in rooms that are at negative pressure to surrounding areas. Depending on the amount of activity and the length of time it is present, special posting may be required (10 CFR 20.1902)

Question 17

If the exposure rate at 4 m from a radioactive source is 5 mR/h, what will the exposure rate be at 3 m?
(a)2.8 mR/h

(b) 6.5 mR/h
(c) 7.4 mR/h
(d) 8.9 mR/h

Answer 17

(d) (I1)(D1)^2 = (I2)(D2)^2

Question 18

A spill of 99mTc increases the exposure rate in a room from 1.7 to 3.15 mR/h. The room is posted with a sign reading “Caution-Radioactive Materials.” What would be the ideal solution?
(a)Change the sign to one reading “Caution-Radiation Area.”

(b) Call the NRC.
(c) Decontaminate the floor with water and cleanser.
(d) Place absorbent paper over the spill and close the room until the activity has decayed.

Answer 18

(d) A sign reading “Caution Radioactive Materials” is required wherever radioisotopes are used. The sign reading “Caution Radiation Area” sign is required if the dose rate exceeds 5 mrem/h, so no change in sign posting is needed. However, the spill should be contained, so restricting access to the area until the activity has decayed to background is the best course of action.

Question 19

A technologist has 500 mrem registered on his ring badge in 1 month. What should be done to decrease exposure in the future?
(a)Use lead pigs and syringe shields when preparing radiopharmaceuticals.

(b) Have another technologist elute the generator.
(c) Wear lead aprons.

Answer 19

(a) All technologists should use lead vials and syringe shields when working with radiopharmaceuticals.

Question 20

OSHA requires that personnel exposure records be provided to employees:
(a)Monthly

(b) Quarterly
(c) Annually
(d) Biannually

Answer 20

(c) OSHA requires that employees are advised at least yearly about their exposure records.

Question 21

A room containing a 57Co sheet source is posted with a sign reading “Caution-Radioactive Materials.” The exposure rate measured next to the source is 5.2 mR/h. What should be done?
(a)Change the sign to one reading “Caution-Radiation Area.”

(b) Store the source in a leaded container.
(c) Monitor the length of time a technologist can work near the source.
(d) None of the above.

Answer 21

(b) According to the NRC regulations for sing posting, the sign should be changed to “Caution Radiation Area,” but a simpler solution would be to store the source in its leaded container.

Question 22

A technologist discovers that a patient in the room next to a radioiodine therapy will receive 2.5 mrem/h when lying in his bed which is against the shared wall. What should be done?
(a)Move the bed to the other side of the room.

(b) Discharge the therapy patient.
(c) Discharge the non-therapy patient.
(d) Calculate how long visitors to the non-therapy patient can stay.
(e) Calculate how long the patient may stay in bed each hour.

Answer 22

(a) Time, distance, and shielding are the most important factors in reducing exposure; in this case, the simplest solution is to employ an increase in distance to the source of the radiation.

Question 23

What is the dose rate limit at the surface of a package bearing a DOT Class I White label?
(a)0.5 mR/h

(b) 2 mR/h
(c) 50 mR/h
(d) 100 mR/h
(e) 200 mR/h

Answer 23

(a) A package with such a label may have an exposure rate that does not exceed 0.5 mR/h at the package surface, and there must be no detectable radiation at 1 m from the package.

Question 24

A type A package bears a DOT Class II Yellow Radioactive label, has a transport index of 0.8, and contains 10 mCi of 111In oxine. What is the exposure rate at 3 ft from the package?
(a)0.4 mR/h

(b) 0.8 mR/h
(c) mR/h
(d) 7 mR/h
(e) Cannot be determined from the information given

Answer 24

(b) The transport index is the dose rate measured at 1 m (roughly 3 ft) from the surface of the package.

Question 25

The doorway to the nuclear medicine reception area should be posted with:
(a)Caution: Radiation Area

(b) Caution: High Radiation Area
(c) Grave Danger: Very High Radiation Area
(d) Caution: Radioactive Materials
(e) None of the above

Answer 25

(e) The sign “Caution Radioactive Area” is posted wherever radioactive materials are used or stored. Unless patients are being injected in the reception area, a sign is not needed.

Question 26

Which of the following steps would not decrease a technologist’s chances of internal exposure to radiation?
(a)Wearing gloves during injection of radiopharmaceuticals

(b) Using tongs to transfer a vial from a lead shield to a dose calibrator
(c) Working under a fume hood when working with volatile liquids and radioactive gases
(d) Refraining from smoking and eating in the “hot lab”

Answer 26

(b) Internal exposure may result from absorption, inhalation, or ingestion of radioactive materials. Using tongs to transfer a vial will not affect the possibility of inhalation or ingestion, and it would only affect the possibility of absorbing radioactive material through the skin if the technologist was not gloved. Using tongs is, however, a good practice to reduce exposure to external radiation as it increases the distance to the source.

Question 27

Tools for measuring personal exposure to radiation include all of the following except:
(a)Thermoluminescent dosimeter

(b) Pocket ionization chamber
(c) Film badge
(d) Geiger-Muller counter

Answer 27

(d) Personnel exposure is measured by all of the choices except the Geiger-Muller counter which is a gas-filled ionization chamber, Because of dead time, it is typically used to measure small amounts of radiation.

Question 28

Which of the following must be done during disposal of a carton in which a shipment of 131I was received?
(a)RSO must be notified.

(b) Carton must be stored for ten half-lives before disposal.
(c) Radioactive labels must be removed or obliterated.
(d) Carton must be discarded with biohazardous waste.
(e) (b) and (c).

Answer 28

(c) Cartons that have been used toe ship radioactive material must have radiation labels removed before disposal. If wipe tests show contamination, it must be regarded as radioactive waste and disposed according to the relevant regulations.

Question 29

If the lead HVL for 99mTc is 2.6 mm and a lead shield containing 99mTc eluate is 13 mm thick, what will the exposure rate be from the shielded vial if the unshielded vial had a rate of 100 mR/h?
(a)1.6 mR/h

(b) 3.1 mR/h
(c) 6.3 mR/h
(d) 12.5 mR/h

Answer 29

(b) The half value layer is the thickness of a material required to reduce the radiation intensity to half. The 12-mm-thick vial contains five half value layers, so the intensity will be reduced to half five times.

Question 30

Reports of area surveys must include all of the following except:
(a)A diagram of the areas surveyed

(b) Equipment that was used to perform the survey
(c) Date performed
(d) Initials of the person who performed the survey
(e) List of isotopes used in the area

Answer 30

(e) NRC licensees are required to prepare and maintain reports of area surveys for 3 years. A list of isotopes used in the area is not a required part of the report.

Question 31

A technologist is working in a hot lab where the exposure rate is 20 mR/h. What sign should be on the door?
(a)Caution: Radioactive Materials

(b) Caution: Radiation Area
(c) Caution: High Radiation Area
(d) Grave Danger: Very High Radiation Area
(e) None of the above

Answer 31

(b) The sign reading “Caution Radiation Area” sign is required if the dose rate exceeds 5 mrem/h. The sign reading “Caution: High Radiation Area” is not required until the dose rate exceeds 100 mrem/h.

Question 32

If a technologist sits 2 ft away from a generator and the dose rate at his chair is 15 mrem/h, what will the dose rate be if he moves his chair 4 ft from the generator?
(a)2.5 mrem/h

(b) 3.75 mrem/h
(c) 7.5 mrem/h
(d) 60 mrem/h

Answer 32

(b) By doubling the distance, the intensity is reduced to one-quarter of the original activity, as shown in the formula below, where I1 is original intensity, I2 is the new intensity, d1 is the original distance from the source, and d2 is the new distance form the source.

I1 / I2 = (d2)^2 / (d1)^2

This can be rearranged to (I1)(D1)^2 = (I2)(D2)^2 for easy solving.

Question 33

A misadministration must be:
(a)Reported within a week to the RSO

(b) Reported to the NRC within 15 days after discovery
(c) Reported to the referring physician within 24 h
(d) Recorded and the records kept for 5 years
(e) All of the above except (a)

Answer 33

(e) A misadministration or other medical event should be reported to the NRC by telephone before the end of the next calendar day and in writing within 15 days. The referring physician should be notified within 24 h. Records of the event should be maintained for 5 years

Question 34

Which of the following is not a misadministration?
(a)When a dose of 400 μCi of 99mTc MAA is given rather than 4 mCi

(b) When the correct dose of 111In oxine for cisternogram is injected intravenously
(c) When a patient who should have been injected with 20 mCi of 99mTc HDP for a bone scan receives a capsule containing 250 μCi of 123I intended for a thyroid patient
(d) When a patient who should have received 50 mCi of 131I receives 35 mCi instead
(e) None of the above

Answer 34

(e) A misadministration can involve the wrong patient, the wrong radiopharmaceutical, the wrong route of administration, or a dose that differs by more than 20% of the prescribed dose or falls outside the prescribed dose range. Doses that differ from the prescribed dose by more than 5 rem effective dose equivalent, 50 rem to an organ or tissue, or 50 rem shallow dose equivalent to the skin are also misadministrations.

Question 35

Which of the following must be kept for 5 years?
(a)Records of misadministrations

(b) Records of dose calibrator linearity
(c) Records of doses assayed before administration
(d) Area survey records
(e) Records of instructions to breast-feeding women who received radiopharmaceuticals

Answer 35

(a) Misadministration records must be kept for 5 years. Records of patient dosage, area survey records, and records of instructions given to lactating females must be kept for 3 years.

Question 36

Records of 99Mo breakthrough in 99mTc eluate must be kept for:
(a)1 year

(b) 3 years
(c) 5 years
(d) 10 years
(e) Until license expires

Answer 36

(b) The NRC states that licensees who use 99Mo-99mTc generators must keep records of the concentration of molybdenum in eluate for 3 years (10 CFR 35.2204)

Question 37

A pregnant technologist receives 350 mrem during her pregnancy according to a film badge worn at waist level. Has the NRC dose limit for the fetus been exceeded?
(a)Yes

(b)No

Answer 37

(b) The total dose limit for a fetus is 0.5 rem (10 CFR 20.1208)

Question 38

What is the best choice for disposal of a vial containing 27 mCi of 99mTc in 2 ml of liquid?
(a)Transfer to an authorized recipient

(b) Incinerate
(c) Bury
(d) Store until decayed to background
(e) Release to the atmosphere through evaporation

Answer 38

(d) If the radioactive material has a half-life of 120 days, the material can be disposed of as ordinary trash after decaying in storage. Before disposal, the material must be surveyed and not be greater than background radiation (10 CFR 35.92). Records must be kept of this for 3 years (10 CFR 35.2092) and must include the radionuclide, the date of disposal, the equipment used to survey the material, the background dose rate, and the dose rate at the surface of the container used for disposal, as well as the name of the person disposing of the material.

Question 39

Which of the following materials is sufficient for shielding a therapeutic dose of 90Y ibritumomab tiuxetan?
(a)Lucite

(b) Tungsten
(c) Lead
(d) None of the above

Answer 39

(a) Because 90Y is a beta emitter, Lucite is an effective shielding material.

Question 40

Any patient who is treated with 90 Y ibritumomab tiuxetan must be hospitalized for at least 24 h.
(a)True

(b)False

Answer 40

(b) The dose is 0.4 mCi/kg and is not to exceed 32 mCi. In general, patients may be released from hospitalization based on measured dose rates or on the basis of activity administered or retained; the activity below which a patient may be released differs according to the isotope (e.g., 33 mCi for 131I). However, for 90Y, 32P, and 89Sr, the NRC does not require hospitalization because the exposure to the public form doses normally used is minimal.