[Planning mobile gamma therapy of cervix cancer]

Moving irradiation of cervical cancer is widely used in radiogynecological practice, mainly as a telecomponent of combined radiation therapy. Its advantages over static irradiation are reduced exposure of the adjacent organs, the absence of skin complications, and a possibility of simultaneous exposure of a primary focus and lymph outflow viae. Biaxial sectoral irradiation was regarded as the most effective method. In order to increase the accuracy and improve the individualized design of moving irradiation according to this method the authors proposed that echotomography be used to determine the depth of the vibration axis. The thickness of subcutaneous fatty tissue was taken into account within the irradiated field in each case. The existing calculating and echotomographic methods for the determination of a position of the vibration axis were compared. Divergence between them was absent in 65% of cases, divergence of up to 1 cm was noted in 28%, up to 2 cm in 31%, up to 3 cm in 20%, and over 3 cm in 14%. Differences were statistically significant. Taking into account a high dose gradient in the sagittal plane the proposed method will make it possible to avoid overirradiation of the bladder and rectum.