It is mostly about calibration of Medical devices. Involves many test acording to Standard operating procedure or work instructions. after the test you have to tabulate the results and fill forms , engeneering side involves measurement of input out put of signals ( current, ampeare volt, range etc ect) and draft report saying that the device falls within the aceptable value. If there is a drift from the aceptable value you have to repair the device so that it will be aceptable to use. (Repair and maintenance)