The movement of isocenter and dose distributions for the partial rotation of cobalt-60 teletherapy werestudied for further effective and accurate treatement planning. The isodose curves for various field size andangulation of the partial rotation therapy were constructed by gammagrams taken under the identical points ofrotation center and the center of 25cm diameter circular phantom. The isodose distributions for partial rotationwere varied according to field size and rotating angulation, shown in Fig. 3, 4. The maximum isocenter from therotation center was displaced and maximum doses for rotation center doses were varied by angulation of rotationand field size, shown in Table I. II.