3-D Printing of Personalized Organ Phantoms

Lukas Zebisch

Imaging and Physics Group, Clinic of Nuclear Medicine, University Hospital Erlangen

February 6 2016

Outline

3-D printing steps

What did we do after midterm presentation?

Suggested improvements

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3-D Printing of Personalized Organ Phantoms

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Segmentation Exporting .stl Post-

processing Generating

.gcode 3-D printing

3-D printing steps:

3-D Printing of Personalized Organ Phantoms

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Segmentation Exporting .stl Post-

processing Generating

.gcode 3-D printing

3-D printing steps:

3-D Printing of Personalized Organ Phantoms

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CT image of a patient with kidneys as volume of interests (VOI). The VOIs were drawn manually and

subsequently used as template for the 3-d print.

3-D Printing of Personalized Organ Phantoms

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Segmentation Exporting .stl Post-

processing Generating

.gcode 3-D printing

3-D printing steps:

3-D Printing of Personalized Organ Phantoms

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Segmented kidney

3-D Printing of Personalized Organ Phantoms

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Segmentation Exporting .stl Post-

processing Generating

.gcode 3-D printing

3-D printing steps:

3-D Printing of Personalized Organ Phantoms

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Post-processed version w. smoothing applied.

3-D Printing of Personalized Organ Phantoms

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Segmentation Exporting .stl Post-

processing Generating

.gcode 3-D printing

3-D printing steps:

3-D Printing of Personalized Organ Phantoms

Used the Cura software and Ultimaker printer:

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3-D Printing of Personalized Organ Phantoms

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Segmentation Exporting .stl Post-

processing Generating

.gcode 3-D printing

3-D printing steps:

3-D Printing of Personalized Organ Phantoms

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3-D printed kidney

3-D Printing of Personalized Organ Phantoms

Goals since midterm presentation 1. Print more kidneys and other organs like livers

2. Integrating a suitable cap to the phantoms

3. Develop a hydrogel for filling the phantom

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http://colinsbeautypages.co.uk/wp-content/uploads/carbomer.jpg

3-D Printing of Personalized Organ Phantoms

Printing of more organs

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3-D printed liver

3-D Printing of Personalized Organ Phantoms

Integration of different fill-port types in a kidney

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3-D Printing of Personalized Organ Phantoms

Printing result and decision

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3-D Printing of Personalized Organ Phantoms

For future printing, the fill-port design depicted on the left was

chosen

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3-D Printing of Personalized Organ Phantoms

Developing a hydrogel for filling the phantom

-> See slides 21 ff.

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3-D Printing of Personalized Organ Phantoms

Further steps/improvements 3-D printing is not yet water-tight:

Idea: Print thicker walls or cover organs with water-tight

painting on the outside

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http://www.portwest.com/wp-content/uploads/sites/2/2013/11/Rain_Symbol.png

Filling Material for Personalized 3D-Phantom for Nuclear Medicine

Nadin Abu-Hossin

Imaging and Physics Group, Clinic of Nuclear Medicine, University Hospital Erlangen

February 06 2017

Requirements on filling material

Goal: Measurement of ionizing radiation dose of

radiocactive tracers

Filling material should mix well with water since

radiopharmaceuticals are usually water based.

Real soft-tissue: Not a liquid Higher viscosity

Higher density than water (~1.05 g/cm3)

First approach: Use of hydrogels

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Definition of Hydrogels

Hydrogel:

„ a gel in which water is the dispersion medium”

Preparation of the hydrogel

Frame-builder: Carbomer, Cellulose, Gelatin,…

Water based Carbomer-Hydrogel

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Preparation of the Carbomer-Gel

Ingredients: Carbomer (Carbopol 980NF)

Water

2% NaOH

Process:

Produce 2%-solution of NaOH

Produce different viscosities: 0.5T – 2.0T in 0.5 steps

Calculation of mass of components in gram

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Recipe of Hydrogels

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0.5T Carbomer 0.649g Carbomer 89.61g Water 9.740g NaOH-Solution

1.0T Carbomer 1.299g Carbomer 78.22g Water 19.48g NaOH-Solution

1.5T Carbomer

1.948g Carbomer 68.83g Water 29.22g NaOH-Solution

2.0T Carbomer

2.597g Carbomer 58.44g Wasser 38.96g NaOH-Solution

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Desnsity measurement of hydrogels

Use X-ray CT for determining the density

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Desnsity measurement of hydrogels

Problems and possible Solutions

Problems

Mean-value of a liver: ~40 HU

Density of current formulation of hydrogels is too low

Possible Solutions

Sugar-solution (saccharose) increasing the density

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Personalized 3-D Phantoms for Nuclear Medicine Dosimetry

Philipp Ritt

Imaging and Physics Group, Clinic of Nuclear Medicine, University Hospital Erlangen

February 06 2017

Summary

Group members: Nadin Abu-Hossin

Lukas Zebisch

Philipp Ritt

SMART Algorithm

-> What have we achieved in the project?

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S.M.A.R.T. Algorithm

Specific Build 3-D phantom from patients’ CT scans

Organs of interest: Kidney, liver, spleen

Phantom should be fillable

Filling-material mimics certain tissue properties (e.g. electron density)

Measurable Get at least one fillable phantom

Compare shapes of phantom with original shape (e.g. DICE coeff)

Compare dose from Monte-Carlo simulations to dose from phantom measurements

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S.M.A.R.T. Algorithm

Achievable/Assignable Yes, BUT: Comparison to real measurement is hard to achieve due

to…

Software: ITK-Snap, Meshlab

Hardware: 3-D Printers, Chemicals for Hydro-Gels

Subtasks

Matteo, Lukas: 3-D Printing

Nadine: Hydro-Gels

Relevant State of the Art

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State of the Art

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S.M.A.R.T. Algorithm

Time bound Several hours per week for each group member

Regular meetings (every Monday)

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Conclusion: Scientific Speed Dating is a promising

new format.

It is a radically different but effective approach for teaching and learning.

BUT, will be hard to achieve „state of the

art“ results within its current limitations.

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Thank you for your attention.

Any questions?