Summary

FDA Phantom Data

Updated: Feb 25, 2010

Summary: As part of a more general effort to probe the interrelated factors impacting the accuracy and precision of lung nodule size estimation, we have been conducting phantom CT studies with an anthropomorphic thoracic phantom containing a vasculature insert on which synthetic nodules were inserted or attached. The utilization of synthetic nodules with known truth regarding size and location allows for bias and variance analysis, enabled by the acquisition of repeat CT scans. Using a factorial approach to probe imaging parameters (acquisition and reconstruction) and nodule characteristics (size, density, shape, location), ten repeat scans have been collected for each protocol and nodule layout. The resulting database of CT scans is incrementally becoming available to the public via the National Biomedical Imaging Archive to facilitate the assessment of lung nodule size estimation methodologies and the development of image analysis software among other possible applications.

Database use

:The database is publicly available for free download thought through the NBIA website (https://imaging.nci.nih.gov/ncia/login.jsf). See the "Data Access" section below for download instructions. The data should not be used for commercial purposes. When using this data in scientific publications or technical reports please cite the following reference:

Marios A Gavrielides, Lisa M Kinnard, Kyle J Myers, Jenifer Peregoy, Sheng Lin-Gibson, Rongping Zeng, Richard Pritchard, Juan Esparza, John Karanian, and Nicholas Petrick, "A resource for the development of methodologies for lung nodule size estimation: database of thoracic CT scans of an anthropomorphic phantom", Optics Express, Special Issue on Imaging for Early Lung Cancer Detection, (submitted, November 2009).
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Please refer to the same reference for more details regarding the development of this database and a discussion regarding its usage.

Database Description

The anthropomorphic thoracic phantom (Kyotokagaku Incorporated, Tokyo, Japan) employed in this study is shown in Figure 1, along with the vasculature insert on which synthetic nodules were attached before CT imaging. The phantom does not contain lung parenchyma so the space within the vascular structure is filled with air.

Fig 1: Photograph of the exterior shell of the thoracic phantom (left) and the vasculature insert (right).

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A key component of the CT lung phantom project is the ability to compare the estimated nodule size with the known true size or reference gold standard. As part of our project, volume was used as a surrogate measure of size. The true volume estimate of each synthetic nodule was derived from weight and density measures. Both the CIRS-and Kyotokagaku nodules were accompanied by density measures. Nodule weights were measured in our lab using a precision scale of 0.1 mg tolerance (Adventurer Pro AV 2646, Ohaus Corp, Pine Brook, NJ). Three repeat weight measurements were made and these weights were averaged to produce a final estimated weight for each nodule. Our estimates of the true volume of the synthetic nodules in each layout are summarized in Table 3 along with approximated xyz location of nodule center in the CT scans.

Data Access

You can view and download these images on NBIA. You do not need to log in unless you want access to advanced features in the site. Simply follow these steps:

• Navigate to http://imaging.nci.nih.gov
• Click the "Search Images" link in the center of the page
• Scroll down through the search criteria until you see the "Collections" section
• Select the "Phantom-FDA" check box
• Press "Submit"

This will return the full list of cases included in the collection. To download the associated DICOM images:

• Press the "Check All" button and then "Add to Basket"
• Press the "View My Basket" button at the bottom of the page (or "View Contents" in the left menu bar)
• Press the "Download Manager" button to open a Java applet and specify where you'd like to save your images