This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thyroid Gland, Subject name: Surgery
In treatment of papillary carcinomas thyroid, radioiodine destroys the neoplastic cells predominantly by: 
Select and explain. 
A. X-rays, B. Beta rays, C. Gamma rays, D. Alpha particles
B: Beta rays
Answer: B: Beta rays 
Explanation: Ans. (b) Beta raysRef: Schwartz 10th edition, Page 1546* I-131 emits Beta radiation and penetrates the thyroid tissue up to 0.5mm without damaging the adjacent structures like parathyroid.