3-D Printing of Personalized Organ Phantoms

Transcription

1 3-D Printing of Personalized Organ Phantoms Lukas Zebisch Imaging and Physics Group, Clinic of Nuclear Medicine, University Hospital Erlangen February

2 Outline 3-D printing steps What did we do after midterm presentation? Suggested improvements 2

3 3-D Printing of Personalized Organ Phantoms 3-D printing steps: Segmentation Exporting.stl Postprocessing Generating.gcode 3-D printing 3

4 3-D Printing of Personalized Organ Phantoms 3-D printing steps: Segmentation Exporting.stl Postprocessing Generating.gcode 3-D printing 4

5 3-D Printing of Personalized Organ Phantoms 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. 5

6 3-D Printing of Personalized Organ Phantoms 3-D printing steps: Segmentation Exporting.stl Postprocessing Generating.gcode 3-D printing 6

7 3-D Printing of Personalized Organ Phantoms Segmented kidney 7

8 3-D Printing of Personalized Organ Phantoms 3-D printing steps: Segmentation Exporting.stl Postprocessing Generating.gcode 3-D printing 8

9 3-D Printing of Personalized Organ Phantoms Post-processed version w. smoothing applied. 9

10 3-D Printing of Personalized Organ Phantoms 3-D printing steps: Segmentation Exporting.stl Postprocessing Generating.gcode 3-D printing 10

11 3-D Printing of Personalized Organ Phantoms Used the Cura software and Ultimaker printer: 11

12 3-D Printing of Personalized Organ Phantoms 3-D printing steps: Segmentation Exporting.stl Postprocessing Generating.gcode 3-D printing 12

13 3-D Printing of Personalized Organ Phantoms 3-D printed kidney 13

14 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 p-content/uploads/carbomer.jpg 14

15 3-D Printing of Personalized Organ Phantoms Printing of more organs 3-D printed liver 15

16 3-D Printing of Personalized Organ Phantoms Integration of different fill-port types in a kidney 16

17 3-D Printing of Personalized Organ Phantoms Printing result and decision 17

18 3-D Printing of Personalized Organ Phantoms For future printing, the fill-port design depicted on the left was chosen 18

19 3-D Printing of Personalized Organ Phantoms Developing a hydrogel for filling the phantom -> See slides 21 ff. 19

20 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 20

21 Filling Material for Personalized 3D- Phantom for Nuclear Medicine Nadin Abu-Hossin Imaging and Physics Group, Clinic of Nuclear Medicine, University Hospital Erlangen February

22 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/cm 3 ) First approach: Use of hydrogels 22

23 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 23

24 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 24

25 Recipe of Hydrogels 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 25

26 26

27 Desnsity measurement of hydrogels Use X-ray CT for determining the density 27

28 Desnsity measurement of hydrogels 28

29 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 29

30 Personalized 3-D Phantoms for Nuclear Medicine Dosimetry Philipp Ritt Imaging and Physics Group, Clinic of Nuclear Medicine, University Hospital Erlangen February

31 Summary Group members: Nadin Abu-Hossin Lukas Zebisch Philipp Ritt SMART Algorithm -> What have we achieved in the project? 31

32 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 32

33 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 Relevant Matteo, Lukas: 3-D Printing Nadine: Hydro-Gels State of the Art 33

34 State of the Art 34

35 S.M.A.R.T. Algorithm Time bound Several hours per week for each group member Regular meetings (every Monday) 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. 35

36 Thank you for your attention. Any questions? 36