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What kind of 3D printers work best for printing from CT scans? In terms of resolution, what have others experienced and what sort of resolutions are needed for the models to actually be used for surgical planning? 

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I've seen some models for surgical planning that were nothing to write home about regarding resolution.  Dr. Mike can chime in, but the rule for resolution should be like it is for any 3d printing project:

 

Given a specific purpose for a model, use the resolution that accurately depicts those features that could be important for that given purpose. A finer resolution isn't necessary

 

Most printers, even low end RepRaps have resolutions down to 0.010" and below which is more than adequate for planning purposes.  The bigger issue for surgical planning will be build size. 

 

Being able to look at a non-adulterated model in 1:1 scale is paramount, especially if the product is being used in the surgical space during a procedure. Build size then is bigger issue. 

 

The final issue is fidelity.  In other words, does the part look like the 3d on-screen version and does that look like the original scan data? That can be tested by creating  a  calibrated on-screen part and then printing it and comparing it to what it's supposed to be. 

 

Anything else you can think of Dr. Mike?

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For bone models I think that the plaster based 3D printers give a nice texture. These printers use superglue to hold the plaster particles together. Polyjet printers are also pretty good with bones. For vascular models I prefer stereolithography. Polyjet doesn't work as well because it is difficult to get the support material out of a vessel. If you can't afford these kinds of printers you can always use a printing service.

 

Low-cost fused deposition printers like Makerbot are OK, but not great. But they have the advantage of being cheap and using inexpensive printing materials. That being said, the new Form 1+ stereolithography printer is $3K, so prices of even advanced printing methods are declining.

 

Anybody else have any first-hand experience with specific types of printers?

 

Dr. Mike

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All the printers I have direct experience with are way upwards of $10,000. Parts look great on them.  I know colleagues who used Makerbots and even experimented with the low end Rep-Rap.  Both built suitable models.  The difference being that the lower priced units require much more hand-holding to get that suitable model. 

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Are there firms out there that specifically print models for surgical planning or is it still not something that is used that often? It seems that there would be a market for companies that provided this service.

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Are there firms out there that specifically print models for surgical planning or is it still not something that is used that often? It seems that there would be a market for companies that provided this service.

 3DSystems will do it as will Materialise.  There are a couple of other players that their names escape me at the moment, but any 3d printing company can do the printing once they get the STL (heck even individuals with a decent printer with connections can do it!) I've had some in depth discussions with folks from 3DSystems and Materialise and they both point out that it's not about printing per se, it's about workflows.   Getting files segmented, cleaned up and then printed in an expeditious manner is the challenge, with emphasis on the 'expeditious' part.  Those two companies alone can handle the printing and even the segmentation, but getting   their services into hospitals as THE provider is the challenge, especially since there still isn't a reimbursement structure in place for 3d printing.  The burden is on the healthcare provider to find a way of getting the prints paid for without losing money.

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I totally agree with mplishka. The two main firms that do surgical planning models are Medical Modeling (now owned by 3D systems) and Materialise. Reimbursement is a major obstacle. Right now, there is no way to get paid for this, so anything you do clinically must be paid for by the hospital or research grant, or is on your own dime. I just returned from Arizona after attending the Mayo Clinic 3D printing in Medical Practice conference and reimbursement was agreed to be a major obstacle. This is why the very limited 3D printing for surgical planning is mainly being done at wealthy institutions that can absorb the cost (like Mayo).

 

FYI, here are a few of the models that were on display at the conference from both Medical Modeling and Materialise.

 

IMG 20150207 091613658

IMG 20150207 091740897

IMG 20150207 091914778

IMG 20150208 103019785 HDR

IMG 20150208 103116586 HDR

 

protohex, I agree that there is a market for a more diverse set of medical 3D printing services, with different price points, materials, turn around times, etc. I've long recognized this. If anybody out there is offering medical 3D printing services (segmentation, design, and printing), please let the community know about your availability by posting in the forums section under services offered. We need more than just two choices!

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There is a very cool technology printing with regular paper.  It can be done in full color and it's much cheaper than other modes of printing and is quick as well.  The challenge is that the print volume is the size of the (double) ream of paper.  The models can be designed to be glued together if larger models are needed.  The models I have seen are always shrunk a little, so this technology may be better for patient education than for surgical planning, but it's still pretty cool.

http://mcortechnologies.com/

 

http://mcortechnologies.com/solutions/medical/

 

The folks at Mcor (they're a hop skip and jump away from me) have the same problems with other 3d printers, regarding adoption.  Reimbursement being the biggie as well.

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Wow I love this forum, there is so much useful insight and information. If obtaining financing for 3D printing service is the major difficulty i wonder how difficult it would be to get such a service covered by insurance companies. 

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Any idea how much an Mcor printer costs? The idea of 3D printing with paper is pretty interesting. Presumably the cost of the print paper is very low. Also paper is nontoxic and easily recyclable. 

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Dr. Mike, I'll get in touch with my Mcor contact and get some current numbers.  You are correct on printing costs: Paper is cheaper and easier to recycle.

Stay tuned!

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Dr. Mike, wasn't able to get a Machine Cost, my contact would like to speak with you first.  Regarding part cost though, compared to traditional methods like SLA, SLS and FDM, it's 80-90% cheaper.  If parts are one color as opposed to multicolor, it's 90-95% cheaper.

I'm getting some whitepapers on case studies using paper - I'll share them once I get them.

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Hey! That's a great article. Thanks for sharing! This is truly a fascinating technology that has a lot of potential. Hope you don't mind if I share your blog post on on our social media outlets.

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Hi guys I am new to this forum and I am really hoping you can help me out here. I am looking to buy a 3D printer that can work with DICOM data in CT scans. In particular, I want to build skull models because thats my area of surgical practice. The models need to be sterilisable (heat resistant) so I can use this in surgical planning intra-operatively. If I can cut the model using a surgical saw (replicating osteotomies) pre-operatively that would also be helpful. In the UK, the national health service will certainly not pay for it, but I can raise some money from a local cancer charity!

Any advice would be greatly appreciated.

Many thanks

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It sounds like you need models for two different purposes. 1) For properative cutting to simulate osteotomies, and 2) intraop guidance. 

 

For preop cutting I would suggest a gypsum powder-based printer like the 3D systems colorjet printers. They print with gypsum power that is bonded together with cyanoacrylic (superglue). The material is cheap and hard, and probably best for simulating bone. However, because some of the powder can come off with handling, I don't thing this can be used intraoperatively. 

 

 

For intraop guidance you might need something like a multijet printer or stereolithography. These solid parts can be sterilized, but they are VERY expensive, both for printers and materials. At RSNA this year they were showing a beautiful liver printed with multijet, but the cost of the print was >$1000. The cost of the printers was $250k!

 

Alternatively, the low-end Cube Pro printer has a build volume big enough for a skull, but there are complaints that it is glitchy. Amazon lists it for $2400. Not sure if the parts can be sterilized.

 

http://www.amazon.com/3D-Systems-Cube-Pro-Printer/dp/B015ZHVLXC

 

Please let us know how your 3D printed models help with your surgeries. I have used them myself for planning of complex endovascular procedures and they can be invaluable. If you need help with converting your CT DICOM files to STL for printing, let me know.

 

Good luck!

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I'll add my 2c in here.  My printers are all FDM based.  They are are most common type these days and have the advantage of being relatively cheap, having a multitude of materials available with new types coming out all time, parts can be made in multiple materials with the right machine, and they can make large functional parts.  

 

The main downsides with FDM is they don't have quite the resolution or quality of SLA (especially for small parts) and it isn't possible to make clear parts (unless they have thin walls).

 

SLA gives good resolution and can be clear but can only create single color/material parts

 

Powder based printers can give decent resolution full color parts but the parts are pretty delicate

 

As to sterilization...

Nylon 680 is compatible with Ethylene oxide and Flash Steam post processing (FDA approved)

 

Autoclave sterilization (120C) is going to to be too hot for most plastics, I have used BluePrint, it has a glass transition temperature of 100C and I can attest to it surviving many trips through my dishwasher but that is not as hot as an autoclave which superheats the steam.  Also 3D printed parts will not be completely solid and thus may not be ideal for being sterilized.

 

As to cutting the models I haven't used a surgical saw on a printed part before but they should work fine other than maybe gumming up the cutting teeth more than the relatively brittle bone. 

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