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File Format Key for Patient Records, Patient Care

Justin Ryan
By Justin Ryan, PhD Director of the 3D Innovations Lab, Rady Children’s Hospital
Justin Ryan, PhD, Director of the 3D Innovations Lab, Rady Children’s Hospital

3D models remains a significant challenge. 3D file formats that are commonly used by printing devices define the topology of a 3D dataset but have no structured mechanism for being reliably incorporated into medical records. There are no means of linking these with the medical imaging on which they are based or describing critical patient information. Formats include STL, G-Code, PLY, VRML, or OBJ, among others. Some of these also lack unit information or capacity for enhanced precision.

 SME and its medical workgroup recognized this problem in 2016. They quickly established communication with the Medical Imaging Technology Association (MITA), which is the Secretariat of the Digital Imaging and Communications in Medicine (DICOM) Standards Committee. This committee is the developer of the DICOM Standard file format, recognized as the ISO 12052 Standard. The goal of communicating between these groups was to solve the problem of managing 3D models to better serve patients and the medical community.

Working Group WG-17 Established

The SME and DICOM dialogue led to the re-establishment of DICOM Working Group 17 (WG-17). The mandate of WG-17 was to bring 3D model files into the DICOM architecture via encapsulation. The implication is that, following proper standards development and adoption, a hospital-based user could create, archive, and query 3D object files via the same mechanism that accesses other medical images.

DICOM has long been the preferred protocol and file format for point of care medical imaging such as X-ray, CT, MRI, and ultrasound. It includes metadata about the institution, patient, and scanning equipment in addition to the payload (e.g., the images or other imaging content). This method of data management and archiving ensures that the images always retain critical information linking them to the patient.

Toward this goal, WG-17 created specifications to formally enable STL and OBJ 3D files to be encapsulated as DICOM objects in June 2018 and January 2020, respectively. The new specifications address deficits in the legacy 3D files, such as providing unit information, object color (for STL), and grouping information (so that multiple STLs and/or OBJs could be stored as an assembly).

Leveraging the existing DICOM specification, a user could create a 3D object and ensure that its spatial coordinates match a source image dataset. Leveraging the existing DICOM IT infrastructure in hospitals, the models could be archived, searched, and exchanged with other facilities, all carefully managed within the patient record.

Promotion and Further Development

DICOM WG-17 is now working on two fronts: promoting adoption and further supporting specification development and enhancement of the specification. Vendor integration will accommodate 3D object viewing in hospital imaging systems and will enable additional traceability of 3D objects through a patient’s electronic health record. This integration ultimately depends on empowering end users to reach out to their vendors and request the support of these DICOM specifications.

On the development front, WG-17 is looking to future 3D file formats such as 3MF, AMF, X3D, and glTF for potential encapsulation. 3MF and AMF both address additional deficits of current 3D formats, such as enabling structured metadata, support for intervertex shape information, or infill information.

WG-17 is looking for more voices from the point of care community to shape future specification. If you have an interest in participating, please visit

There is no cost to observe or join a Working Group. To vote in the Working Group, members must sign a patent declaration agreement. To vote in the DICOM Standard Committee, there is a membership fee.

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