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Summary

Lack of access to projection data from patient CT scans is a major limitation for the development and validation of new CT reconstruction algorithms. However, patient projection data acquired using commercial CT scanners are stored in a proprietary format, requiring investigators to have research agreements in place with the CT manufacturer to be able to read the data correctly. These proprietary data formats make it unlikely that investigators will be able to validate their algorithm on data from more than one manufacturer.

To meet this critical need, researchers at the Mayo Clinic, with funding from the National Institute of Biomedical Imaging and Bioengineering (EB 017095, EB 017185), have built a library of CT patient projection data in an open and vendor-neutral format. This format, referred to as DICOM-CT-PD, is an extended DICOM format that contains CT projection data and acquisition geometry. The de-identified patient projection data in the library were decoded with help of the manufacturer and have been converted into an open and standard format.

Acknowledgements

We would like to acknowledge the individuals and institutions that have provided data for this collection. 

  • A complete list of acknowledgements can be found here.

Data Access

Click the Download button to save a ".tcia" manifest file to your computer, which you must open with the NBIA Data Retriever. Click the Search button to open our Data Portal, where you can browse the data collection and/or download a subset of its contents.

Data TypeDownload all or Query/Filter
Images (DICOM, 1.32 TB)

 

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(Requires NBIA Data Retriever.)

DICOM-CT-PD User Manual Version 2.3b (.pdf)


Matlab DICOM-CTPD data dictionary (.txt)

Matlab DICOM-CTPD reader script (.txt)

Clinical Data (CSV, zip)

Click the Versions tab for more info about data releases.

Detailed Description

Image Statistics


Modalities

CT

Number of Patients

299

Number of Studies

598

Number of Series

1,047

Number of Images

13,009,241

Images Size (TB)1.32

Investigators at the Mayo Clinic, with funding from the National Institute of Biomedical Imaging and Bioengineering (EB 017095, EB 017185), have built a library of CT patient projection data in an open and vendor-neutral format. This format, referred to as DICOM-CT-PD 1, is an extended DICOM format that contains CT projection data and acquisition geometry. The de-identified patient projection data in the library were decoded with help of the manufacturer and have been converted into an open standardized format.

Reconstructed images, patient age and gender, and pathology annotation are also provided in these de-identified data sets. The library consists of scans from various exam types, including non-contrast head CT scans acquired for acute cognitive or motor deficit, low-dose non-contrast chest scans acquired to screen high-risk patients for pulmonary nodules, and contrast-enhanced CT scans of the abdomen acquired to look for metastatic liver lesions.

For each scan, three types of data are provided, including DICOM-CT-PD projection data, reconstructed CT images, and a CSV file. CT data are provided for both full and simulated lower dose levels, albeit reconstructed image data of the lower dose projection data are available only for the data from Siemens Healthcare, where we were able to return the lower dose data to the scanner for reconstruction with their commercial filtered-back-projection algorithm. Several instructional documents are provided to help users extract needed information from the DICOM-CT-PD files, including a dictionary file for the DICOM-CT-PD format, a DICOM-CT-PD reader, and a user manual.

This collection comprises 99 head scans, 100 chest scans, and 100 abdomen scans. For each scan type, the 50 currently available cases are from a SOMATOM Definition Flash CT scanner (Siemens Healthcare, Forchheim, Germany). Additionally, 50 cases each for chest and abdomen and 49 cases for head scans are included from a Discovery CT750i scanner (GE Healthcare, Waukesha, WI). Work is underway to include data from a 3rd CT manufacturer (Philips Healthcare, Best, Netherlands). Together, these data will greatly facilitate the development and validation of new CT reconstruction and/or denoising algorithms, including those associated with machine learning or artificial intelligence.

Acquisition protocol

All CT scans were acquired at routine dose levels for the practice at which they were obtained using standard-clinical protocols for the anatomical region of interest. Each clinical case was processed to include a second projection dataset at a simulated lower dose level.  Head and abdomen cases are provided at 25% of the routine dose and chest cases are provided at 10% of the routine dose.

1Additional information regarding the CT projection data format: Chen B, Duan X, Yu Z, Leng S, Yu L, McCollough CH. Technical Note: Development and validation of an open data format for CT projection data. Med Phys. 2015;42(12):6964. (doi: https://doi.org/10.1118/1.4935406.)

Citations & Data Usage Policy

These collections are freely available to browse, download, and use for commercial, scientific and educational purposes as outlined in the Creative Commons Attribution 3.0 Unported License. See TCIA's Data Usage Policies and Restrictions for additional details. Questions may be directed to help@cancerimagingarchive.net.

Please be sure to acknowledge both this data set and TCIA in publications by including the following citations in your work:

Data Citation

McCollough, C.H., Chen, B., Holmes, D., III, Duan, X., Yu, Z., Yu, L., Leng, S., Fletcher, J. (2020). Data from Low Dose CT Image and Projection Data [Data set]. The Cancer Imaging Archive. (DOI goes here.)

Grant Citation

Presentations and publications shall acknowledge grants EB017095 and EB017185 (Cynthia McCollough, PI) from the National Institute of Biomedical Imaging and Bioengineering.

TCIA Citation

Clark K, Vendt B, Smith K, Freymann J, Kirby J, Koppel P, Moore S, Phillips S, Maffitt D, Pringle M, Tarbox L, Prior F. The Cancer Imaging Archive (TCIA): Maintaining and Operating a Public Information Repository, Journal of Digital Imaging, Volume 26, Number 6, December, 2013, pp 1045-1057. DOI: 10.1007/s10278-013-9622-7

Other Publications Using This Data

TCIA maintains a list of publications which leverage TCIA data. If you have a manuscript you'd like to add please contact the TCIA Helpdesk.

Version 1 (Current): Updated yyyy/mm/dd

Data TypeDownload all or Query/Filter
Images (DICOM, 1.32 TB)

 

Download button not active

(Requires NBIA Data Retriever.)

DICOM-CT-PD User Manual Version 2.3b (.pdf)


Matlab DICOM-CTPD data dictionary (.txt)

Matlab DICOM-CTPD reader script (.txt)

Clinical Data (CSV, zip)

Added new subjects.






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