Priors: DICOM Viewer

Priors opens the scan files from your imaging disc, or from the zip your clinic sent you, and draws the images on your screen. It never reads them for you.
Everything happens on this device. Nothing is uploaded, to us or to anyone else.

WHAT THIS IS
A viewer for the MRI, CT or X-ray files you were given at the imaging center. You pick the zip or the files, Priors reads them, and the pictures appear. That is the whole app. There is no account, no sign in, and nothing to fill in first.

WHAT YOU CAN DO
- Move through every slice with the slider under the image.
- Set your own brightness and contrast by dragging on the image.
- Pinch to zoom in, double tap to fit the image back to the screen.
- Flip the image between light on dark and dark on light.
- Switch between the series in your study. Priors keeps them apart using the series id written inside each file, so two different series never get stacked into one.
- Read a plain list of the files that did not open, with the reason for each one.

Priors runs on iPhone and iPad.

WHAT IT DOES NOT DO
Priors does not read your images for you. It adds no marks, no scores and no notes of its own. It is not a medical device. Your radiologist's report is the medical record.

Educational review, never a diagnosis. This app does not review anything at all. It shows you your own images and stops there.

WHICH FILES OPEN
Priors reads uncompressed 8 bit and 16 bit grayscale DICOM images, which is what most clinic discs hold. It reads them loose, or inside a zip, and the files can have any name or no file extension at all.

WHICH FILES DO NOT OPEN YET
Compressed DICOM, multi frame images, color images, and files with no series id do not open in this version. Neither does the DICOMDIR index file some discs carry. When a file will not open, Priors names it and says why, instead of quietly dropping it.

HOW TO GET YOUR DISC ONTO THIS PHONE
A phone has no disc drive, so the trip is one hop through a computer.
1. Put the disc in a computer that has a disc drive.
2. Copy the whole disc folder to the desktop.
3. On a Mac, right click the folder and choose Compress. On Windows, right click the folder, choose Send to, then Compressed folder.
4. AirDrop the zip to this phone, or save it into Files, iCloud Drive, Google Drive or Dropbox.
5. Open Priors, tap Open a file or a zip, and pick that zip.

If your clinic gave you a download link or a zip instead of a disc, save that file into Files and start at step 5.

TRY IT WITHOUT A FILE OF YOUR OWN
A sample study is built into the app. Its images are computer generated, they are not a real person, and they are labeled that way everywhere they appear.

PRIVACY
Priors makes no network requests at all. There is no account, no sign in, no analytics, no advertising, no crash reporting, and nothing to buy inside it. The app asks for no permissions at all: no camera, no photo library, no contacts, no location. It opens the file you hand it, through the standard iOS file picker or by choosing Priors from the share sheet. The files you open are read here on your device and are never sent to Priors or to anyone else. The working copies Priors makes are removed when you close a study, and deleting the app takes everything with it. The full policy is at priors.health/privacy

Priors is a viewer. It shows the images in your own scan files and nothing more. It does not interpret them, it is not a diagnosis, and it is not a medical device. It is not intended for diagnostic use. Always talk to a qualified clinician about your images and your results.