Chapter 2: Radioactivity, Radiopharmacy, and Quality Assurance

Nuclear Medicine Technology Review Questions 5th Ed.pdf

How does ²⁰¹Tl decay?

By electron capture

What is the role of the stannous ion in the preparation of pharmaceuticals labeled with Tc-99m?

To reduce the valence state of Tc-99m 

If an assay of a vial containing I-131 shows 50 mCi present on May 2, approximately what will the assay show on May 18?

12.5 mCi 

If a bone scan has been ordered on a 5-year-old girl and the physician prescribes 62% of the adult dose to be given, how many mCi should be administered?

12.4 mCi

If the biological half-life of an isotope is 6 h and the physical half-life is 12 h, what is the effective half-life?

4 h

Which of the following is used to abbreviate physical half-life?

T_p

The physical half-life of a radionuclide is the time it takes:

For the nuclide to decay to one-half of the original activity

If a kit has 310 mCi of activity present at 8:00 a.m., what will the vial assay show in 4 h and 10 min if the decay factor is 0.618?

192 mCi

A vial containing Tc- 99m is assayed at 9:00 a.m. and contains 255 mCi. Calculate the remaining activity at 3:00 p.m?

127.5

A vial of technetium eluate contains 50 mCi/ml. If 4 ml is withdrawn and added to a diphosphonate kit containing 16 ml of solution, what volume would then need to be withdrawn to prepare a 20 mCi dose at that moment?

2.0

If a preparation of 9mTc mertiatide has 60 mCi of activity present at 8:30 a.m., how many mCi will be present at 9:00 a.m, (DF = 0.944)?

56.6

Which of the following is boiled during preparation?

Sulfur colloid 

The presence of 12 ug Al⁺³ in 1 ml of Tc-99m eluate is:

An example of chemical impurity

Which body decides on the acceptable levels of radionuclidic impurity?

NRC

Which of the following is an example of radionuclidic impurity?

Presence of Mo-99 in Tc-99m eluate

What is the maximum amount of aluminum ions (AI⁺³) allowed in 1 ml of Tc-99m eluate according to the USP?

10 ug

What is indicated by the front of an instant thin layer chromatography (ITLC) strip?

Pyrogens

If a kit contains 140 mCi of Tc-99m in 23 ml, how much volume must be withdrawn to obtain a dose of 5 mCi?

0.8 ml

If a kit contains 140 mCi of mTc in 23 ml at 9:00 a.m., how much volume must be withdrawn to obtain a dose of 5 mCi at 3:00 p.m.?

1.6 ml

An MAA kit contains 40 mCi of Tc-99m in 5 ml at 8:00 a.m. What would be the best volume to be withdrawn for a 4 mCi dose at 10:00 a.m. if a perfusion lung scan is planned (=0.794)?

0.63 ml

What is the most likely size of an MAA particle if correctly prepared?

10-30 um

Tc-99m MAA has a biologic half-life of 2-4 h; what will the effective half-life be?

Which radiopharmaceutical is made with Tc-99m without a reducing agent?

Sulfur colloid

Which of the following is an example of radiochemical impurity?

Presence of free Tc-99m in a preparation of 99mTc sulfur colloid

Which of the following can be said regarding effective half-life?

It is always shorter than both the physical and the biologic half-life.

The purpose of adding EDTA to sulfur colloid when labeling with Tc-99m is:

Both

A diphosphonate kit should generally be used within how many hours after preparation?

4-6 h

What is the usual particle size of sulfur colloid?

0.3-1.0 um

Which radiopharmaceutical, when correctly prepared, will have the smallest particle size?

Tc-99m human serum albumin

The advantages of albumin colloid over sulfur colloid include:

Does not require heating

Following injection of Tc-99m MAA for a perfusion lung scan, activity is seen in the kidneys and brain. This is indicative of:

Right-to-left cardiac shunt

At 7:00 a.m., a technologist prepares a dose of Tc-99m MDP for injection at 10:00 a.m. that day. The desired dose is 22 mCi and no precalibration factors are available. The 3-h decay factor for the isotope is 0.707. What amount of activity should the technologist draw up into the syringe at 7:00 a.m.?

31.1 mCi

What can be said regarding precalibration factors?

Both 

What method is used to calculate pediatric dose?

All of the above

If the recommended volume for a MAG3 kit ranges from 4 to 10 ml, and the Tc-99m eluate that will be used contains 820 mCi in 10 ml, and 41 mCi will be used, what is the minimum amount of diluent that should be added?

3.5 ml

If a 20 mCi dose of Tc-99m HDP is needed at 9:00 a.m., how much activity should the syringe contain if the technologist prepares it at 7:00 a.m.? You may use the table of precalibration factors (Table 1) to determine the answer.

25.18 mCi

Using table 2, determine the decay factor for Tc-99m at 7 h

0.445

On a Monday morning at 6:00 a.m., a technologist is preparing a Tc-99m BCD kit that is to be used for SPECT brain scan injections at 8:00 a.m., 9:00 a.m., and 10:00 a.m. Each patient should receive 10 mCi. What is the minimum activity that should be added to the kit during preparation? Use Table 1 if necessary.

42.6 mCi

A chromatography strip is used to test a kit for radiochemical impurity and is counted in a well counter. Part A contains Tc-99m pertechnetate, and Part B contains bound Tc-99m in the desired form. If the results show 258,000 cpm in Part B and 55,000 cpm in Part A, can this kit be used for injection into patients?

No

What is the approximate radiochemical purity for the kit described in question 39?

82%

What is the approximate radiochemical impurity of the kit described in question 39?

18%

A vial of 99mTc eluate is tested for "Mo breakthrough, and the amount of breakthrough is 25 uCi in 775 mCi at 6:00 a.m. Following the preparation of all kits to be used that day, 450 mCi of Tc-99m is left. That night, a technologist is asked to perform a scrotal scan at 11:00 p.m. Must the generator be eluted again?

Yes, because the molybdenum breakthrough will now exceed the limit allowed by the NRC

A Tc-99m MDP bone scan dose was prepared at 7:00 a.m. and contained 32 mCi/2 ml. At 9:00 a.m., when the patient arrives, the technologist realizes that the patient's age was overlooked (13 years). The technologist would now like to adjust the dose to 11 mCi. Given a 2-h decay factor of 0.794, what volume should be discarded so that the correct dose remains in the syringe?

1.13 ml

A dose of Tc-99m DMSA is prepared and calibrated to contain 5.0 mCi at 8:00 a.m. The patient arrives late at 10:00 a.m. Without using any tables of decay factors, determine what activity will remain in the dose at that time.

3.97 mCi

An MAA kit contains 950,000 particles per ml. The activity in the kit is 50 mCi of Tc-99m in 5 ml. If a 4 mCi dose is drawn up, how many particles will be in the dose?

380,000

What happens to the dose in Q45 if it sits for 1 hour?

The number of particles per mCi will increase.

A volume of 5 ml containing 40 mCi of Tc-99m is added to an MAA kit with an average of 3,000,000 particles. What volume of the reconstituted kit should be withdrawn to prepare a dose for a patient with severe pulmonary hypertension?

0.25 ml

To reduce the possibility of pyrogenic reactions, all kits should be prepared using saline that contains bacteriostatic preservatives.

False

While performing a GI bleeding study with labeled red blood cells, a technologist notices gastric activity that he suspects is the result of free pertechnetate. What could be done to support this suspicion?

Image the thyroid

Convert 23 mCi to SI units.

from 850 to 851 MBq

If excessive aluminum is present in Tc-99m eluate, which of the following would be expected on a bone scan?

Liver uptake

Radiochemical impurities often result from:

Both

It is proper technique to clean the septum of a kit reaction vial and inject an amount of air equal to the volume being withdrawn when preparing a unit dose

False

15 rem is equal to

150 mSv

What is the purpose of adding hetastarch to a blood sample drawn for the purpose of leukocyte labeling?

To hasten the settling of erythrocytes

Following reconstitution of a kit with Tc-99m pertechnetate, a technologist should ensure that all of the following are present on the vial except:

Patient name or identification number

If the proper centrifuge speed is not used during separation of cell types for leukocyte labeling with In-111 oxine, what may happen?

Platelets may be inadvertently labeled

In most reconstituted radiopharmaceutical kits, in what form is Tc-99m present?

All of them

For determination of plasma volume, 10uCi of human serum albumin in 2.5 ml is added to 500 ml of water. What is the concentration of the resulting solution?

0.019 uCi/ml

A Mo-99/Tc-99m generator exists in ______ equilibrium and the parent

isotope has a _____ physical half-life than the daughter isotope.

Transient, longer

If 630 mCi of Tc-99m is eluted from a Mo-99/Tc-99m generator, what is the NRC limit of total Mo-99 activity that may be present?

94.5 uCi