Quality Control (Q&A Book)

The percentage of radioactivity in a preparation originating from the de sired radionuclide is called __________ purity.

radionuclidic

The maximum permissible amount of 99Mo per mCi (per 37 MBq) of 99mTc is __________.

0.15 µCi per mCi (0.15 kBq per MBq)

The radionuclidic purity of 99mTc __________ during the day because of the longer physical half-life of 99Mo compared with 99mTc.

decreases

An important cause of impurity in 123I preparations is __________.

124I

A multichannel analyzer may be used to assess radionuclidic purity by evaluating the __________ of the sample.

energy spectrum

The energies of 99Mo photons are __________ and __________.

740 keV; 780 keV

A simple, common method used to evaluate for the presence of 99Mo in 99mTc samples uses a dose calibrator and __________.

a lead shield (pig) to differentially absorb the low-energy photons, while allowing the energetic 99Mo photons to pass

The percentage of total radioactivity present in a preparation in the desired chemical form is called the __________ purity.

radiochemical

The presence of free 99mTcO4 −1 (pertechnetate) in a 99mTc–red blood cell (RBC) preparation is an example of a __________ impurity.

radiochemical

In 99mTcO4 −1 preparations, the three general forms of technetium are free pertechnetate, chelated technetium, and __________.

reduced hydrolyzed technetium

Reduced hydrolyzed technetium has a tendency to be taken up by which organ of the body?

The liver.

The form of technetium that is con centrated by the thyroid and gastric mucosa is __________

99mTcO4-1 (pertechnetate)

If it is suspected that gastric activity on a bleeding scan is a result of free pertechnetate, then one should image the __________ to confirm.

thyroid

The most common means of evaluating radiochemical purity is by use of __________.

instant thin layer chromatography

As a general rule of thumb for radio pharmaceuticals made with 99mTcO4 −1 , the radiochemical purity should be __________.

at least 90%

__________ impurity refers to the presence of nonradioactive compounds in a preparation that may interfere with the normal behavior or safety of the radiopharmaceutical.

Chemical

A common source of chemical impurity that originates from the 99Mo/99mTcO4 −1 generator is __________.

aluminum from the alumina column

The presence of excess amounts of aluminum in a 99mTc–sulfur colloid preparation leads to excess uptake in this organ of the body.

The lungs.

The presence of excess amounts of aluminum in a 99mTc–methylene diphosphonate (MDP) preparation leads to excess uptake in this organ of the body.

The liver.

The presence of aluminum in a generator eluate can be tested by__________.

indicator paper (aurintricarboxylic acid)

The permissible quantities of aluminum in a fission 99Mo generator eluate are __________.

less than 10 µ/mL eluate

The presence of excess amounts of stan nous ion in a 99mTc–MDP preparation leads to excess uptake in this organ of the body.

The liver.

Macroaggregated albumin should be of what particle size?

90% between 10 and 90 µm diameter

Sulfur colloid should be of what particle size?

0.1 to 1 µm.

Fever-producing toxins that often originate in gram-negative bacteria and may contaminate radiopharmaceuticals are called __________.

pyrogens

The rapid method of testing for pyro gens is __________.

the limulus amebocyte lysate (LAL) assay (which uses the blood of the horseshoe crab, Limulus polyphemus)

The formal method of testing for pyro gens is by __________.

injecting the sample into rabbits and monitoring their temperature

Is endotoxin much more or much less toxic when radiopharmaceuticals are administered into the cerebrospinal fluid (CSF) compared to systematically administered preparations?

Much more.

The absence of viable microbes with in a radiopharmaceutical is called __________.

sterility

When there are increased counts at the periphery of the scintillation crystal due to internal reflection of light at the edges, the phenomenon is called __________.

edge packing