PURPOSE: To evaluate the efficacy of a newly designed cassette and film system used to obtain a craniocaudal(CC) image during mammographic examination. MATERIALS AND METHODS: We designed a film-cassette system for use inobtaining a CC image. The merit of this system is that the contact plane between the film and film cassette andthe thoracic wall of the examinee changed from linear to concave, thus including more tissue on the image. Twentywomen examined by screening mammography underwent conventional and new CC plane examinations. The distance fromthe nipple to the posterior margin of the included breast tissue, as seen on CC mammograms, was measured using thetwo techniques, and the difference between the respective results was analyzed by paired t-test. RESULTS: Thedistance from the nipple to the posterior margin was 12.9 +/-1.7cm and 14.5 +/-1.4cm at the lateral portion of theconventional and new CC image, respectively. This distance was thus significantly greater on the new than on theconventional image (p<0.001), but there was no significant difference between their me-dial portions. CONCLUSION:The newly designed cassette and film system used to obtain a craniocaudal image during mam-mography includes morebreast tissue than the conventional system and may be helpful for the mammograph-ic screening and diagnosis ofperipheral breast lesions.