Alkaline phosphatase (ALP) mostly comes from either from bone disease or liver disease. Typically, a GGT is also measured and, if elevated, can suggest liver disease. The fact that the ALT and AST were not markedly elevated suggests an absence of liver pathology.
That leaves bone diseases - the bone scan is a reasonable test to evaluate for this. It can suggest if there is any bone-related disease present (i.e. bone cancer, myeloma etc.). The ultrasound is another screening test for liver disease. In effect, I would agree with the approach being taken.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
Medical Weblog:
kevinmd_b
God bless