Radiological apparatus, such as bone densitometry measurement systems that utilize a penetrating radiation source, such as an x-ray source is provided. The apparatus includes a patient table with a length extending along a Y-axis and a width extending along an X-axis and a C-arm supporting, for example, an x-ray source at one side of the table and an x-ray detector at an opposite side of the table such that the source and detector are aligned along a source-detector axis. The source is energized to emit a fan beam of x-rays which conform to a beam plane which is transverse to the Y-axis and contains the source-detector axis. Either, or both, the C-arm or the table are selectively movable relative to the other along the X-axis, along the Y-axis, and along a Z-axis which is transverse to both the X-axis and the Y-axis, so that selected regions of a patient on the table can be selectively scanned with the fan beam of X-rays. In addition, the C-arm is selectively rotatable around a rotational axis extending along the Y-axis to selectively change the angle of the fan beam relative to a patient on the table.