Doctor encounters a number of problems when making these decisions:
a)    Doctor treating a patient is basically experimenting on that patient.  Doctor really does not know until he has actually provided the treatment, whether the patient will benefit from such treatment; he only suspect that the patient will benefit.
b)    Problems in evaluating new technology.
(1)    There may be some lag time between the development of a device and the literature to the doctor and the acceptance of the community.
(2)    Problems with over-diagnosing by radiologist.
(a)    EX: MRI – radiologists may over read the x-ray and determine there is a ruptured disc b/c of defensive medicine.