Guide for labeling medical imagery.

When creating a project, select DICOM.

Import DICOM data

For more information on the import format, see our docs on DICOM import format.


Data row size limit

To view the maximum size allowed for a data row, visit our limits page.

Supported annotation types

Below are all of the annotation types you may include in your ontology when you are labeling DICOM data. Classification-type annotations can be applied at the global level and/or nested within an object-type annotation.

FeatureImport annotationExport annotation
PolylineSee payloadSee payload
Segmentation mask*See payloadSee payload

* You must use the video segmentation tool.


Use the Polyline tool to label lines in a DICOM slice. Click on the last point to complete the shape.

Segmentation mask

Pen Tool

Use the pen tool to outline the item in the image. Hold the cursor down to draw freehand or let the cursor go to draw straight lines between points. The pen tool is only available when creating segmentation annotations. Click the pen icon with the plus sign to use the pen tool.

Brush Tool

With the brush tool, you can use brush strokes to quickly draw a mask. You can change the brush size using the slider at the top. There are two options for the shape: circle and square.

Erase tool

You can use the erase tool to clean up the edges of a segmentation mask. The tool is available for both the pen and brush tools. Click the respective icon with the minus sign to use the erase tool.

DICOM-specific hotkeys

Opt + ScrollZoom in and out of the slice.
Control + Click + Pan up/downAdjust the contrast of the slice selected.
Control + Click + Pan left/rightAdjust the brightness of the slice selected.
Shift + ClickPan around the image.