True/False Indicate whether the
statement is true or false.


1.

Calculating the time that has elapsed since the time at which the activity was
known is referred to as initial activity or original activity.


2.

The exponent .693 is the natural log of 2 which accounts for the halving of
activity with each half life.


3.

Because a radionuclide is constantly decaying at a specific rate, the activity
is constantly increasing.


4.

The Universal Decay Table allows you to determine the decay factor for any
radionuclide based on the half life and elapsed time.


5.

If you know the activity and half life of a radionuclide, you can calculate the
activity for any time in the future or the past.


6.

The amount of decrease per unit of time is dependent upon the half life of the
radionuclide.

Multiple Choice Identify the
choice that best completes the statement or answers the question.


7.

If dipyridamole is supplied in a 50ml vial containing 250mg, and a patient
weighs 205 pounds, how much volume will need to be withdrawn from the vial to prepare the dose with a
concentration of 0.56mg/kg?
a.  22.6ml  c.  15.9ml  b.  10.4ml  d.  5.6ml 


8.

If the halfvalue layer (HVL) for I131 in lead is 0.3 cm, what is the minimum
thickness of lead that is required to reduce the exposure rate of the I131 source from 12 mR/h to
less than 2 mR/h?
a.  0.3 cm  c.  0.6 cm  b.  0.9 cm  d.  1.2 cm 


9.

If a MDP kit contains 230 mCi of Tc99m in 9 ml at 7am, how much will have to be
withdrawn for a 20 mCi dose at 1:00pm?
a.  1.6 ml  c.  1.9 ml  b.  0.6 ml  d.  0.8 ml 


10.

Determine the 4 hour Decay Factor for I123, half life is13.2
hours.
a.  .8105  c.  .8052  b.  .8111  d.  .8815 


11.

If a bulk vial of Tc99m produces an exposure rate of 350 mR/hr at 1 cm from the
surface, what is the exposure rate at 10 cm from the surface?
a.  None of these answers are correct  c.  2.4 mR/hr  b.  3.5
mR/hr  d.  35
mR/hr 


12.

If a kit has 310mCi of activity present at 8am, what will the vial assay show in
4 hours and 10 minutes if the decay factor is 0.618?
a.  155mCi  c.  501mCi  b.  175mCi  d.  192mCi 


13.

If 740 kBq of a radiopharmaceutical are to be administered for each kilogram of
body weight, approximately how much activity (in MBq) should be administered to a patient who weighs
172 pounds?
a.  280 MBq  c.  78 MBq  b.  9.5 MBq  d.  59 MBq 


14.

Determine the 15 hour Decay Factor for Molybdennum 99, half life is 66.6
hrs.


15.

A vial contains 200mCi of an unidentified radionuclide at 10am Thursday. At 10am
Friday, the activity has decayed to 50 mCi. What is the halflife of the unidentified
radionuclide?
a.  100 hours  c.  4 hours  b.  12 hours  d.  24 hours 


16.

Convert 752 mCi to MBq:
a.  789  c.  28724  b.  20.32  d.  27824 


17.

A 20 mCi dose of Tc99m MDP results in a total body absorbed dose of .25
rads. This value is equivalent to:
a.  .25 Gy  c.  .5 mSv  b.  .25 rem  d.  2.5 mGy 


18.

If a kit contains 140mCi of Tc99m in 23ml at 8:00am, how much volume must be
withdrawn to obtain a dose of 5mCi at 3:00pm? DF: .4459
a.  1.7ml  c.  1.84ml  b.  1.6ml  d.  2.4ml 


19.

What is the easiest and most practical way for a technologist to reduce the
radiation exposure from a patient?
a.  keeping a distance  c.  lead shielding and barriers  b.  limiting your time
around the patient  d.  concrete 


20.

A 10 mCi dose of Tc99m MAA is equal to what activity in MBq?
a.  37 Bq Tc99m MAA  c.  3.7 Bq Tc99m MAA  b.  370 MBq Tc99m MAA  d.  37 MBq Tc99m
MAA 


21.

From the above question, what volume must withdrawn at 11am? DF= .4695
a.  not enough information  c.  2.84 cc  b.  5.28 mCi/cc  d.  17.84 mCi 


22.

A unshielded syringe of 15 mCi of F18 FDG is producing an exposure rate of 160
mR/hr at 1 meter. What is the exposure rate at 3 meters?
a.  480 mR/hr  c.  53.3 mR/hr  b.  17.7 mR/hr  d.  2844 mR/hr 


23.

If the exposure rate at 4 meters from a radioactive source is 5 mR/hr, what will
the exposure rate be at 3 meters?
a.  6.5 mR/hr  c.  2.8 mR/hr  b.  7.4 mR/hr  d.  8.9 mR/hr 


24.

How much activity of Tc99m MDP would you have at 3pm if you started with 200
mCi/cc at 7am? Half life of Tc99m is 6.01 hrs.
a.  121 mCi  c.  103 mCi  b.  512 mCi  d.  79 mCi 


25.

1356 uCi =? mCi
a.  135.6 mCi  c.  .1356 mCi  b.  1.356 mCi  d.  13.56 mCi 


26.

A vial has 45mCi @ 8am. What is the approximate activity @ 12pm? DF:
.630
a.  36mCi  c.  18mCi  b.  25mCi  d.  28mCi 


27.

If 175 mR/hr were measured @ 1ft, what would be the exposure rate @ 5
feet?
a.  17mR/hr  c.  4mR/hr  b.  7mR/hr  d.  20mR/hr 


28.

A Tc99m DTPA kit contains 198 mCi in 7.6 cc’s. What is the specific
concentration of the solution?
a.  26.1 mCi  c.  26.1 mCi/cc  b.  26.1 cc  d.  26.1 cc/mCi 


29.

A syringe of Gallium 67 Citrate contains 12.8 mCi in 4.1 cc. What is the
specific concentration?
a.  3.12 cc/mCi  c.  3.12 mCi/cc  b.  3.2 mCi/cc  d.  3.12 mCi 


30.

At some point in time a source has an activity of 1,000 mCi. At a later point in
time the activity is 31.25 mCi. The halflife is unknown. How many halflives have elapsed?
a.  three  c.  can’t be determined from data provided  b.  five  d.  four 


31.

One Bq = ?
a.  37 billion dps  c.  one dps  b.  one curie  d.  3.7 x 10 dps 


32.

Convert 1575 uCi to kBq:
a.  58275  c.  58000  b.  1612  d.  42.56 


33.

A F18 FDG bulk vial contains 60 mCi in 4.6 cc’s. If a 4 mCi dose is
needed, how many cc’s must be administered?
a.  .39 ml  c.  3.9 mCi/cc  b.  13.04 mCi/cc  d.  .3 cc 


34.

10 mCi F18 Sodium Fluoride was calibrated for 7am. The patient does does
arrive until 8am. What is the activity of the dose at 8am? (DF=.6852)
a.  6.4 mCi  c.  7 mCi  b.  6.8 mCi  d.  8.6 mCi 


35.

A 4 mCi Tc99m MAA is needed at 4pm. If the dose is being prepared at
2pm, how much activity must be used?
a.  4.5 mCi  c.  8 mCi  b.  5.04 mCi  d.  5.8 mCi 


36.

If an assay of a vial containing I131 shows 50mCi present on May 2,
approximately what will the assay show on May 18? (Half Life I131= 8.02 days)
a.  6mCi  c.  25mCi  b.  12.5mCi  d.  40mCi 


37.

A vial of Thallium 201 Chloride must contain 120 mCi of activity at 8am on
Tuesday. If the vial is prepared at the radiopharmacy at 10am on Monday, how many mCi’s
are needed? (Half life of Thallium 201 is 73.1 hours)
a.  139 mCi  c.  175 mCi  b.  147 mCi  d.  210 mCi 


38.

A vial contains a mixture of 20mCi of I124 (halflife=4 days) and 6mCi of I131
(halflife 8 days). What will be the activity in the vial 8 days from now?
a.  3mCi  c.  5mCi  b.  8mCi  d.  13mCi 


39.

From the above equation, what volume of radiopharmaceutical would be needed to
prepare the 30 mCi dose?
a.  not enough information  c.  .38 ml  b.  1.3 ml  d.  can not do the
procedure 


40.

A bulk vial of F18 FDG contains 135 mCi in 12 ml at 9am . A 15 mCi dose is
needed for a wholebody study to stage cancer, what volume must be withdrawn right now?
a.  15 mCi  c.  11.25 mCi/ml  b.  1.3 cc  d.  1.6 ml 


41.

If a technogist works in a Nuclear Medicine Department for 8 hours per day, and
the ambient background exposure rate is approximately 1.3 mR/hr. What is the approximate total
amount of radiation exposure this technologist will receive in one work day?
a.  1.04 mRems  c.  10.4 mRems  b.  13.8 mRems  d.  10.4 Rems 


42.

If a MDP kit contains 230 mCi of Tc99m in 9 ml at 7am, how much will have to be
withdrawn for a 20 mCi dose at 1:00pm?
a.  0.8 ml  c.  0.6 ml  b.  1.9 ml  d.  1.6 ml 


43.

A technologist must administer 37 MBq of Thallium 201 at 12 am on February
16. Based on the vial label information shown here, what volume should be administered to the
patient:
Calibration: 12:00 Noon: February 14 Total Activity: 222 MBq Total
Volume: 4.0cc Concentration: 55.5 MBq/cc Expiration: 1200: Noon: February
17 Half life: 3.04 days
a.  1.6 cc  c.  2.1 cc  b.  1.05 cc  d.  1.1 cc 


44.

A vial contains 180mCi in 5 ml. Approximately what volume is required for
25mCi?
a.  0.9ml  c.  0.7ml  b.  0.5ml  d.  1.2ml 


45.

A vial of TcO4 eluate contains 150mCi/ml. If 4 ml are withdrawn and added to a
kit containing 16 ml of solution, what volume would need to be withdrawn to prepare a 20 mCi dose at
that moment?
a.  2.5ml  c.  1.5ml  b.  2.0ml  d.  .67 ml 


46.

Calculate the Effective half life: P= 73 hours: B= 10 days: What is the
Effective half life of Thallium 201?
a.  56 hours  c.  2.33 hours  b.  110 hours  d.  43 hours 


47.

A 15 mCi F18 FDG syringe unshielded produces an exposure rate of 15 mR/hr to
the hands. If the technologist places a tungsten syringe shield over the syringe equivalent to
2 half value layers of attenuation absorption, what is the new exposure rate?
a.  None of these answers are correct.  c.  13 mR/hr  b.  .6
mR/hr  d.  3.75 mR/hr



48.

A Tc99m RBC kit contains 40 mCi in 5 cc of whole blood at 0800. What would
be the best volume to be withdrawn at 10:00 if a GI Bleed Scan for a patient with an acute bleed is
needed STAT? The prescribed dose is 5 mCi. DF: .7939
a.  1.78 cc  c.  .63 cc  b.  .063 cc  d.  .79 cc 


49.

From the above calculations at 3pm, you have an Add on patient who needs 30 mCi
of Tc99m MDP for a triphasic bone scan to rule out osteomyelitis. Do you have enough
radiopharmaceutical at 3pm?
a.  no clue  c.  no  b.  yes  d.  not enough
information 


50.

On July 24 a solution of I131 contains 100uCi. What was the activity on July 1?
DF: .789
a.  300uCi  c.  800uCi  b.  400uCi  d.  200uCi 


51.

A Tc99m Sodium Pertechnetate dose that is to be drawn up at 8am, the dose must
be calibrated for 10 mCi at 11am. How many mCi’s are needed at 8am? (Physical Half life
of Tc99m is 6.01 hours)
a.  10.4  c.  27.2  b.  18.4  d.  14.1 


52.

The eluate from a Mo99/Tc99 Generator contains 368 mCi in 5 ml. What is
the concentration of the eluate?
a.  78.3 mCi/ml  c.  18.65 mCi/ml  b.  73.6 mCi/ml  d.  373 mCi/ml 


53.

A dose equivalent of 20 mSv is equal to:
a.  2 rem  c.  1 rem  b.  2 mrem  d.  1 mrem 


54.

Onehundred twentyseven millicuries is equivalent to how many
megabecquerels?
a.  4699 MBq  c.  4.6 E 2 MBq  b.  4,699 Bq  d.  3.4 MBq 


55.

If a kit has 310mCi of activity present at 8am, what will the vial assay show in
4 hours and 10 minutes if the decay factor is 0.618?
a.  155mCi  c.  175mCi  b.  501mCi  d.  192mCi 


56.

Calculate the Effective half life for Tc99m MDP using the following data:
Physical: 6.01 hours: Biological: 11 hours:
a.  Effective= 3.9 days  c.  Effective= 1 day  b.  Effective = 1 hour  d.  Effective = 3.9
hours 


57.

A unit dose of Gallium 67 Citrate is calibrated for 8am on July 9 measuring 5
mCi in 2.6 cc’s. if 3 mCi’s are needed on July 10 at 8am, what volume should be
retained in the syringe? (Half life of Gallium 67 is 3.26 days)
a.  1.8 cc  c.  1.53 mCi  b.  1.96 cc  d.  3.98 mCi/cc 


58.

If the HVL of Cobalt 60 in lead is 1.25 cm, what percentage of the photons are
absorbed from a shielded vial containing 2.5 cm of lead?


59.

If a unit dosage of radioactivity contains 4.5 mCi in 1.2 ml, how many
milliliters must be removed so that 3.5 mCi remain in the syringe?
a.  0.93 ml  c.  0.42 ml  b.  0.27 ml  d.  0.78 ml 


60.

If the exposure rate at 10 meters from a cobalt sheet source is 15 mR/hr, what
will the exposure rate be at 25 meters?
a.  3 mR/hr  c.  2.4 mR/hr  b.  6 mR/hr  d.  10 mR/hr 
