This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Radiotherapy Pa 1, Subject name: Radiology
Gamma Rays Are used in which Diagnostic Modality ? 
Select and explain. 
A. Fluoroscopy, B. CT Scan, C. MRI, D. Bone scan
D: Bone scan
Answer: D: Bone scan 
Explanation: Gamma Rays are used in Radioisotope studies/scintigraphy studies Bone scan is a radioisotope study done using Tc99m -MDP to detect skeletal metastasis Fluoroscopy and CT scan uses Xrays Radiowaves are used in MRI