Objective: To know the influence of twilight by using the radiotherapeutical technique box on hormonal function of ovaries. The aim of transposition of ovaries by radical hysterectomy of the cervical cancer is to move the ovaries out of radiotherapeutical target volume, and thus to protect their hormonal function. Setting: Institute for the Care of Mother and Child, Prague, Czech Republic. Methods: Computer simulation of radiation isodoses of linear accelerator on the transfered pictures of CT and calculation on the total dose, and radiobiological equivalent outside the target volume of radiation regarding the total dose of 46Gy. Results: In the pelvis region the minimal dose succeeded in acting as a castrating dose. The safe area is 2.5 cm above the margin of the radiation beam. Conclusion: It can be recommended to tuck the ovaries 3.5 cm above the margin of the pelvis.

        Key words: cervical cancer, ovarial transposition, radiobiologic equivalent, linear accelerator, target volume