A simplified shielding approach for limiting fetal dose during radiation therapy of pregnant patients.

Abstract

To investigate the effectiveness of a simple and practical shielding device to reduce fetal dose for a patient undergoing radiation therapy of nasopharyngeal carcinoma. Using 5-cm-thick lead bricks and a heavy-duty steel cart, a 50 x 50-cm portable shield was designed and fabricated to reduce fetal dose due to collimator scatter and head leakage radiation. With the gantry at 90 degrees /270 degrees the shield can be easily positioned between the machine head and the fetus to reduce peripheral dose. Dose measurements for 6-MV X-rays and 9-MeV electrons have been made, utilizing a Rando phantom, to quantify the effect of the shield. Measurements show that the peripheral dose to the fetus can be reduced by 60% when the simple shielding device is used.