Sample Written Exam – Nuclear Medicine

Sample Written Exam – Nuclear Medicine Question 1 List THREE types of coincidence events that occur in PET imaging. [...] For EACH type, describe how the event rate varies with activity level. [...] Ignore dead-time effects. MODEL ANSWER (1 mark each, 3 marks total) • Trues (increase linearly with activity) • Scatter (increase linearly with activity) • Randoms (increase quadratically with activity – since they go as the square of the singles rate) Question 2 List FOUR factors that affect the performance of a parallel hole collimator. [...] MODEL ANSWER (0.5 marks each, 2 marks total) • Number of holes • Hole diameter • Hole length • Septal thickness • Distance of object from collimator Question 3 Name the medication you would administer in the following scenarios. State the usual adult dose for each drug. [...] a) Patient with severe adverse effects following dipyridamole infusion: MODEL ANSWER (0.5 marks for each correct drug, 0.5 marks for each correct dose) • Aminophylline 50-250 mg IV If route of administration is absent, this is OK, but if given and is incorrect, may deduct 0.25 marks. b) Assessment of cerebral perfusion reserve: MODEL ANSWER (0.5 marks for each correct drug, 0.5 marks for ea [...] MODEL ANSWER (0.5 marks each, 2 marks total) • Whole body irradiation • Iron therapy • Gadolinium (for MRI) • Chemotherapy Question 5 Use the table below to calculate the following values: Disease State Positive Disease State Negative Total Test Positive 9 1 10 Test Negative 11 99 110 Total 20 100 120 a. [...] Sensitivity: MODEL ANSWER (1 mark) • Sensitivity TP/(TP+FN) = 9/20 = 45% b. Specificity: MODEL ANSWER (1 mark) • Specificity TN/(TN+FP) = 99/100 = 99%3 c. [...] Positive predictive value: MODEL ANSWER (1 mark) • Positive Predictive Value = TP/(TP+FP) = 9/10 = 90% d. Negative predictive value: MODEL ANSWER (1 mark) • Negative Predictive Value = TN/(TN+FN) = 99/110= 90% e. [...] Test accuracy: MODEL ANSWER (1 mark) • Test Accuracy (TN+TP)/total = 108/120 = 27/30 = 9/10 = 90%