What is appropriate investigation?

A 70-year-old man with prostatic cancer has had severe acute back pain waking him up at night for 6wks.

What is appropriate investigation?
A . DEXA scan
B . Serum ALP concentration
C . Serum calcium concentration
D . MRI spine

Answer: A

Explanation:

Radionuclide bone scan. MRI is good for soft tissue but not for bone. If it was radiculopathy, spina compression or prolapsed disc creating pressure on nerve MRI would be fine but not for bony metastasis. Her choice is radionuclide bone scan.