RSNA Releases Guidelines for Medical 3D Printing

Part of the thrill of 3D printing is in that sense of lawlessness: experiencing the ability to create and manufacture on a whim. In the medical field, however, rules and regulations are a good thing as none of us want to be misdiagnosed, treated with the wrong medications, or become the victim of a botched surgery.

The Radiological Society of North America (RSNA) is taking 3D printing very seriously as a technology that can be integrated with radiology, but they are also promoting consistency and safety, as outlined in their document, ‘Radiological Society of North America (RSNA) 3D printing Special Interest Group (SIG): Guidelines for medical 3D printing and appropriateness for clinical scenarios,” written by volunteer members.

Ambitions toward creating printing guidelines have been in the works since 2016 with the approved creation of the Special Interest Group on 3D Printing.

“These practice parameters and recommendations are not intended as comprehensive standards but do reflect several salient aspects of clinical anatomic modeling and appropriateness,” state the authors.

Using 3D printing to create models for patient-specific care includes the following steps:

• Image acquisition
• Image segmentation
• Creation of 3D printable file types
• 3D printing
• Post processing of models

The point of the RSNA document is to offer recommendations on the 3D printing of medical models, including ‘point-of-care manufacturing’ in hospitals and clinical settings. Content for the document was discussed during several different meetings of the RSNA Special Interest Group for 3D Printing, with recommendations covering the following parameters for 3D printing:

• Spatial resolution and slice thickness
• Signal to Noise Ratio (SNR) and Contrast to Noise Ratio (CNR)
• Image artifacts
• Image data preparation and manipulation
• File storage and descriptors
• Reference to file manipulation and alteration

Of special interest is the recommendation regarding 3D printed models:

“When 3D printed models are generated from medical images, the resolution of the 3D printer should be equal to, or superior to that of the clinical images used to segment the model.

“… Printed models are assumed to be of anatomic size (1:1) unless a scaling factor is otherwise noted. Additional identifiers such as model sidedness (left, right) should be noted, as appropriate. Institutional guidelines should be used to verify models are free of protected health information, or models are handled appropriately in accordance to Health Insurance Portability.”

Supporting materials should be removed completely, and if a 3D printed model is defective and cannot be repaired, it should be re-printed. Not only should models be inspected fully, but so should 3D printers, being assessed for continued accuracy, including test prints, preventative maintenance, and recalibration.

And regarding bioprinting:

“Manufacturers should provide cleaning recommendations and specifications for materials which have been formally tested for biocompatibility and sterility, and these specifications should be followed by the facility. Additional internal sterilization policies may exist depending on the hospital.”

Additionally, the document also goes into detail discussing many different specific descriptions submitted by the SIG writing group for each clinical group.

3D printed models are becoming more prevalent in the medical field, whether as training devices for medical students and surgeons or use in simulation but issues have been raised more often lately too regarding guidelines and quality assurance methods. Find out more about RSNA guidelines here, as trends continue in accountability for 3D printing.

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[Source / Images: Radiological Society of North America (RSNA) 3D printing Special Interest Group (SIG): Guidelines for medical 3D printing and appropriateness for clinical scenarios]