Consultants in Nuclear Medicine
2910 W. Estes Ave 
Chicago, IL 60645
Phone: (773) 802-7617    
FAX:  (773) 304-2545  
E-mail: nucmedconsultants@comcast.net

Our comprehensive answer key is available. We have recently revised it with ~75 new questions and answers. In addition, the answer key is now almost 150 pages and has ~ 500 questions, containing the questions and the answers rather than just the answers. The answer key has not only the correct answers, but also an explanation of why each answer is correct. Problems are solved in a logical step-by-step order and reference is made to keys on a standard scientific calculator. 

These practice exams/answer keys are NOT available in electronic format; you will receive a high-quality photocopy of a laser-printed original.

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Text

Question 1. The Tc-99m eluted from the Mo-99/Tc-99m generator is in the chemical form of
    a) pertechnetate (Tc04-1)
    b) HR Tc, e.g. Tc0(OH)2.(H20)
    c) Technetium hydroxide, e.g. Tc(OH)4
    d) Technetium sulfate, e.g. Tc(S04)2
    e) None of the above
 
Correct answer:  a.  Na pertechnetate is the most highly oxidized chemical form of Tc, in which the oxidation number is 7+. Choice b is incorrect. Hydrolyzed reduced Tc is an insoluble colloid localizing in the RES. Choice c is also incorrect and represents an insoluble form. Choice d is impossible since sulfate is not used to elute the generator.

Question 2. The parent/daughter relationship in a Mo/Tc generator is a classical example of
    a) dynamic stability
    b) secular equilibrium
    c) transient equilibrium
    d) reverse isomeric transition
    e) none of the above
 
Correct answer: c.  Transient equilibrium is reached when the parent’s half-life is approximately 10 times that of the daughter. In this case, the half-life of Mo-99 (67 hr) is 11 times that of Tc-99m (6 hr), producing a ratio of 11:1. The Mo/Tc generator is considered an ideal example of transient equilibrium. Choices a and d are incorrect since they don’t even represent types of equilibrium. Choice b is also incorrect since the requirement for secular equilibrium is that the half-life of the parent be >> half-life of the daughter, e.g., 100:1 or greater.