1. A method for determining bone mineral density values of an object to be examined by way of a computerized tomography system, the method comprising: acquiring first two-dimensional projection overview image data of the object to be examined in an image detail with a first X-ray energy; acquiring at least second two-dimensional projection overview image data of the object to be examined in an image detail with at least one second X-ray energy, which differs from the first X-ray energy; determining a bone overview image data record using the first projection overview image data and the second projection overview image data; determining at least one specific evaluation region of the image detail using the bone overview image data record; and determining a bone mineral density value for the specific evaluation region of the image detail using the image data of the bone overview image data record in the specific evaluation region.