CK512 File

What are CK512 files and how to open them

Are you having problems opening a CK512 file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your CK512 files.

What is a CK512 file?

A .CK512 file is a CyberKnife Treatment Image file.

A CyberKnife Treatment Image is a proprietary radiographic image used by the CyberKnife System for tracking and verification of patient setup and motion during radiosurgery or stereotactic body radiation therapy. It is created by the system's onboard kilovoltage (kV) X-ray imagers during treatment delivery and used for quality assurance, motion compensation, fiducial or marker tracking, and live image‐guide registration with treatment planning data.

Its creation workflow involves an X-ray imager panel capturing raw detector data that are exported in a vendor native format (such as "HIS" or "raw"). These images are then processed or converted by auxiliary software tools (for example, open source toolkits or treatment planning/QA systems) into standard formats like DICOM so that image review, evaluation, or integration with other imaging modalities becomes possible.

The image resolution is typically 512 by 512 pixels; pixel intensity is 12-bit (stored in 16-bit unsigned integer values) in many Cyberknife treatment image sets. The file begins with a short header containing metadata (including image dimensions), followed by the raw pixel data. It is not a DICOM image in its native stored form. It is identified by a signature at the very start: the ASCII bytes "###51251200" (hex 23 23 23 20 35 31 32 32 20 35 31 32 20 30 30 20 30 30) at offset zero.

How to open CK512 files

Important: Different programs may use files with the CK512 file extension for different purposes, so unless you are sure which format your CK512 file is, you may need to try a few different programs.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

Last updated: August 31, 2026

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