Sonometry and densitometry medical diagnostic devices enabled for per-use patient examinations charged via internet connections to financial cards

The invention is in the field of medical diagnostic devices such as equipment for estimating properties of bone from ultrasound or x-ray measurements or for obtaining other medical diagnostic information, and in the field of methods of using such equipment. More specifically, the invention pertains to facilitating per-use charging for utilizing such equipment. A system of fee-per-exam charging for the use of medical devices such as bone sonometers and x-ray densitometers. The customer or custodian of the device purchases a number of patient exams from the manufacturer or supplier of the equipment over an Internet connection with the company web site and receives a unique code that, when entered into the equipment, enables it to carry out the purchased number of patient examination and thereafter become disabled.