Osirix is one of the finest radiological (DICOM) image viewers out there, and best of all it is free and open source. Now you can also enjoy that goodness on your iPad, with Osirix HD. A (paid) iPhone version has been out for a while, but of course the iPad screen lends itself much better for image viewing than the small iPhone screen. Osirix HD has been released just a few days ago as a universal app for iPhone and iPad, and costs $29.99. It can display images from all common imaging modalities, such as ultrasound, CT, MRI or PET scans. It can be used as a complement to the desktop version, providing seamless integration, or by itself connecting to a PACS server to retrieve images over WiFi or 3G. Basic image manipulation can be performed using the common iOS gestures. The main limitations are that images are limited to 1024x1024 pixels (bigger images are down-sampled) and the app is not FDA approved, so you are not supposed to use it for clinical diagnoses. The full feature list (from the press release):Display and browsing through large sets of images through an interactive slider
Zoom and Pan and rotation of the images through two-fingers drag and pinch
Contrast and intensity adjustment of image window and level through single finger drag
Rapid switch between image series through single finger screen "swipe"
Reset to image default size and setting through double tap
Measurement of object sizes using a line measurement tool that can be set and adjusted by two fingers
Measurement of image content data using a circular region of interest tool that can be drawn and moved with two fingers
DICOM compliant Listener (C-STORE SCP)
DICOM Query and Retrieve (C-FIND SCU, C-GET SCU, C-MOVE SCU, WADO)
JPEG2000/JPEG DICOM support
Preference setting for user DICOM communication settings
Access to desktop database through web-based portal for retrieving image data
Built-in help