Type:
Educational Exhibit
Keywords:
Computer applications, Anatomy, CT, Image manipulation / Reconstruction, Computer Applications-3D, Computer Applications-Detection, diagnosis, Prostheses, Dysplasias, Education and training
Authors:
A. Varma, R. Olivotto, A. Hodgkinson; QLD/AU
DOI:
10.1594/ranzcr2018/R-0068
Imaging findings OR Procedure details
DIFFERENT TYPES OF 3D MODELLING:
7 Main types-all use different technologies (Fig.4)1
- Vat Photopolymerization
- Material Extrusion (the type our printer does)
- Material Jetting
- Binder Jetting
- Powder Bed Fusion
- Direct Energy Deposition
- Sheet Lamination
SOFTWARE:
- 3D printers do not accept DICOM images.
A standard file format to define 3D models is Standard Tessellation Language (STL).
The STL format defines surfaces as a collection of triangles (called facets) that fit together like a jigsaw puzzle.
-
AMF has been designed to overcome many of the limitations of the simple STL format,
such as enabling the user to incorporate features including surface texture,
color,
and material properties into each part.
POST PROCESSING:
- 3D printing involves accurate segmentation of the desired tissues,
then saving the segmented areas as an STL file.
- Often CT Workstations will have an application that allows exportation of STL files.
VITREA© (Fig.
5-8) produced by VITAL Images is the software of choice at the Mater Hospital.
- The STL file can then be further edited using a basic 3D modeling program.
The Mater Hospital uses 3D Builder (Free software available with Microsoft Windows 10) (Fig.
9-10)
- The STL file is then loaded into another program which 'slices' the model into a series of layers.
Multiple parameters (such as speed,
fill density,
supporting structure,
wall thickness,
etc,
etc) are edited,
then a .gcode file is produced.
This is a file type that basically tells a machine (in this case a 3D printer) how quickly and what direction to move.
- Fig. 11 Summerises the steps involved in turning a 2D DICOM images into a 3D Model.
WHICH PRINTER TO CHOOSE:
This depends on many factors:
- Most important: Intended use -Surgical planning/education/prosthesis size assessment and custom prosthesis.
Other Technical Requirements to consider:
- Cost of printer and materials.
- Choice of materials.
- Color capabilities.
- Material temperature and moisture resistance.
- Molding or casting properties.
- Whether a 3D printer with multimaterial capabilities is necessary.
MATER HOSPITAL SETUP:
Creatbot DX Plus (Fig.
12)
- This printer was chosen due to its large build platform (30cm x 25cm x 52cm) This allows the printing of a full spine or femur.
Other advantages include:
- a heated build platform (allows better adhesion of base layer)(Fig.13)
- 3 nozzles (allows 3 different materials to be use in one print)(Fig.13)
- 4 cooling fans (faster cooling allows faster printing) (Fig.14)
CLINICAL APPLICATIONS IN OUR DEPARTMENT:
CARDIAC (Fig.16-18)
ORTHOPEDICS (Fig.19-22)
NEURO (Fig.23-25)
PLASTICS (Fig.26)
CRANIO AND MAXILLOFACIAL SURGERY (Fig.26-36)
NON-CLINICAL:
PT EDUCATION-Visually describe surgical technique/approach to patient
TEACHING/EDUCATION OF PARAMEDICAL STAFF- Allow better understanding of 3-Dimensional anatomical relationships by direct visualisation
CASE STUDIES:
Fibrous Dyslasia in 15yr old female (Fig.28-29) ?Surgical remodelling.
3D print allows better visualisation of surface anatomical relationships.
This print uses 2 different nozzles-yellow for fibrous tissue,
red for normal bone.
Apert's syndrome in 15yr old male (Fig.30-33).
Previous surgical fixation of fractured left angle of mandible.
Post op infection and subsequent fracture proximal to implant.
Due to malalignment of mandible,
custom bent fixation was used.
The surgical team bent the plate to the shape of the patient's mandible using the 3D printed model.
This allowed much faster surgical time (2hrs less),
better fixation,
better fitting implants and a smaller surgical incision.
Blowout fracture in 44yr old male (Fig.
34-36).
3D printed model to aid in mesh size and positioning.
Mesh bent and moulded to shape from the 3D model prior to surgery.
Perfectly fitted and secured the first time.
3D Printing allows better surgical outcomes for patients by reducing surgical time and providing better fitting implants.