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

Purpose: To investigate the effectiveness of a simple and practical shieldi ng device to reduce fetal dose for a patient undergoing radiation therapy o f nasopharyngeal carcinoma, Methods and Materials: 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 fe tal dose due to collimator scatter and head leakage radiation. With the gan try 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 phan tom, to quantify the effect of the shield. Results: Measurements show that the peripheral dose to the fetus can be red uced by 60% when the simple shielding device is used. (C) 2001 Elsevier Sci ence Inc.