Blog
Plain-language guides to DICOM files and scan CDs, from the team behind Radix DICOM, a DICOM viewer for your phone. For personal and educational viewing only, never for diagnosis.
CT and MRI scans: studies, series and slices explained
A scan on a disc is organised as a study, made of series, made of slices. What each level means, how CT and MRI differ, and why a folder has so many files.
Multi-frame DICOM and cine loops on a phone
A multi-frame DICOM holds many frames in one file and plays as a short cine loop. What it is, why it is large, and how to step through it on a phone.
Why a DICOM file will not open, and what to try
A DICOM file that will not open is usually not an image, is incomplete, or sits in the wrong folder. Practical checks to run before you ask for a new copy.
DICOM tags and metadata: what the fields mean
DICOM tags are numbered fields stored inside the file, such as patient name, modality and image size. How they are written and which common ones to know.
DICOM viewer privacy: why offline beats uploading your scan
A DICOM scan holds your name, birth date and images. Here is what an offline viewer does differently from one that uploads, and how to check any app.
DICOMDIR explained: how a patient scan CD is organised
DICOMDIR is the index file on a patient scan CD. What it lists, how the folders are laid out, and what to do if the file is missing or the images have no extension.
How to open a .dcm file without installing hospital software
You do not need the hospital program to view a .dcm file. Free options on Windows, Mac, Linux, in a browser and on Android, and what to weigh for each.
How to open a DICOM scan CD or USB on your phone
A phone cannot read a scan CD directly. Copy the whole disc to a USB stick or the phone from a computer, then open the folder in a DICOM viewer.
Reference lines on CT and MRI: what they mean
Reference lines show where one slice sits in another plane of the same scan. How they are drawn from DICOM position tags, and why they sometimes do not appear.
How to share a DICOM scan for a second opinion
Send the whole study folder, not screenshots. How to zip a DICOM scan, what to include from a CD, and why to ask the receiving clinic how it wants the files.
What is a DICOM (.dcm) file and what is inside it?
A .dcm file is a medical image plus the details that describe it. What the file holds, how it is laid out, and why one scan is often hundreds of files.
Window and level explained: why a CT looks different
Window width and level decide which range of values becomes black, grey and white. Why one CT can look very different, and what presets really are.