This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Radiology
For shield (mould) in eye tumors which of the following is preferred? 
Select and explain. 
A. Iodine-131, B. Gold-198, C. Strontium-90, D. Phosphorous-32
D: Phosphorous-32
Answer: D: Phosphorous-32 
Explanation: Ans. D. Phosphorous-32Some useful radionuclides used in clinical radiotherapyRadionuclideEnergy Half-life Medical uses* Radium-2260.83mv1625 yearsfor brachytherapy but not used now a days* Cobalt-601.25mv5.4 yearsteletherapy & brachytherapy* Caesium-1370.666mv30 yearsteletherapy & brachytherapy* Iridium-1920.380mv72 daysbrachytherapy only* Iodine-1250.030mv60 daysbrachytherapy* Iodine-1310.61mv8 daysunsealed radioiodine for thyroid cancer Rx* Gold-1980.412mv 2.7 days brachytherapy* Strontium-902.24mv30 yearsfor shield (mould) in eye tumors* Phosphorous-321.71mv14 daysintraperitoneal