In an X-ray computer tomograph and a method for investigating an object by means of X-ray computer tomography, to improve the image quality, a first intensity of the X-ray radiation between an X-ray source and the object is measured by means of a first intensity measurement device (13) and a second intensity of the X-ray radiation between the object and the X-ray detector outside a projection region of the object is measured by means of a second intensity measurement device. A scattered radiation correction factor is calculable by means of the measured intensities to reduce the scattered radiation.