The terms “Ground Penetrating Radar” and “X-Ray” are sometimes used interchangeably. But they are not the same thing, and do not describe the same process. X-Ray scans cannot be used to locate underground oil tanks, as X-Ray scans require physical access to both the top and bottom of the substance being scanned. The construction industry uses X-Ray scans when examining the concrete slabs in multi-story structures such as apartment buildings and parking garages. However, an X-Ray scan is of no use at all when hunting for underground oil tanks.