[en] In efforts to reduce the dose of X-ray exposure in mass screenings for gastric cancer, we devised lead acrylic fitters and evaluated their effectiveness using a phantom. We found that our 6 mm, 12 mm, and 24 mm filters reduced the exposure dose by 14.30%, 14.30%, and 21.40%, respectively. The reduction of the depth dose-rate calculated by the position of the stomach was 4.95%, 7.06%, and 9.34%, respectively. There was no visually discernible difference in the density of gastric images on the X-ray films obtained with or without the filters. When we measured the size of the gastric images and the filter shadows, we found that the gastric images overlapped the filter shadows in 332 of 473 (70.2%) clinical cases. However, the filter shadows presented no diagnostic disadvantage. Based on our findings, we suggest that lead acrylic filters should be introduced into mass screenings for gastric cancer to reduce the dose of X-ray exposure. (author)