The dose profiles at the center and the places 1cm away from the surface of a standard dosimetry phantom of a head were measured with thermoluminescent dosimeters (TLD) by using a Hitachi W-1000 CT system. Regression equations for the scattered radiation dose as a function of the distance from the radiation center were obtained by fitting the measured data. The CT dose index (CTDI) was different from those computed by integrating over different intervals. Some problems worthy of special attention were discussed. This study provides a technical base for CT dose monitoring and promoting application of International Basic Standard of Radiation Protection and The Safety of Radiation Source (IBSS) guide level.