This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Radiology
All of the following radioisotopes are used as systemic radionucleide, except – 
Select and explain. 
A. Phosphorus-32, B. Strontium- 89, C. Iridium-192, D. Samarium-153
C: Iridium-192
Answer: C: Iridium-192 
Explanation: Radionuclides used for systemic radiotherapy are 32P, 131I, Strontium - 89, Samarium - 153, Yttrium, and Rhenium.