**1. Introduction**

Since the introduction of the Apple iPad in April 2010, the use of the mobile tablet PC has increased rapidly and such devices now comprise a major portion of the PC market.

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

With new developments in technology, opportunities for the use of tablet PCs in hospitals for management or diagnosis have increased because of the great advantages they have in terms of portability and applications for teleradiology [1–4]. An increasing number of reports have compared the use of mobile device screens with liquid‐crystal displays (LCDs) for diagnosis, and the accuracy of the former is now considered to be almost equal to that of the latter, or at least acceptable, for MRI diagnosis of spinal injury, radiography and CT diagnosis of intracranial hemorrhage and orthopedic injury, and CT diagnosis of pulmo‐ nary embolism [5–8].

The viewing of digital mammograms using a soft‐copy reading device has many advantages in terms of image display, better handling, postprocessing capability, computer‐assisted diag‐ nosis, archiving of image information, and image data transmission [9]. High‐grade (so‐called medical purpose) LCDs, such as the 5‐megapixel (MP) LCD, are recommended for soft‐copy reading in digital mammography [10–12].

Recently, a high‐resolution 4K color display has also been developed and is commercially available. 4K resolution refers to a display device or content having a horizontal resolution in the order of 4000 pixels. Several examples of 4K resolution exist in the fields of digital televi‐ sion and digital cinematography. To our knowledge, however, there is no definite consensus as to whether a 4K high‐resolution display monitor would be acceptable for reading of mam‐ mograms. In terms of access, portability and cost effectiveness, it would be useful to clarify whether 4K images actually afford better diagnostic accuracy.

The purpose of this study was to assess the observer performance of 4K tablet PCs with a high‐resolution calibrated grayscale display monitor for detection of breast cancers on digital mammograms, in comparison with 5‐MP LCDs.
