I actually do have a busy clinical job, lol, I've just had the time to write up and photograph several long-term projects lately. Anyhow, if you all are sick of me turning r/MedicalPhysics into a 3D printing subreddit let me know and I'll lay off.

For those doing modified W/L shots daily, this phantom bolts onto an MPC phantom and makes setup more consistent and faster for the therapists. After MPC completes, they can just run couch to 120 LNG from outside the room and start the W/L QA patient. Our therapists appreciate everything we can do to speed up their morning routine.

(There is certainly room for debate whether MPC is adequate for daily radiation/imaging isocenter checks. If I had my way, we would just go with the MPC. Hot take! :) )

Get the Files for free! https://www.printables.com/model/1810391-mpcp-daily-winston-lutz-phantom-w-attachment-to-mp

Full Collection of stuff: https://www.printables.com/@MakingMedicalPhysics/collections/3562991

Someone asked. Here's a quick 1 minute video: https://youtu.be/Vmh7NobGvew

This is very Eclipse specific. This is the best way I have come up with -- takes just a few minutes but makes patient setup so much faster. Any skin marks they may have had in CT are usually long gone.

TLDR: use temporary reference points to transfer cutout edge back to "contouring".

If someone has a better way please share!

Get it here! BTG JigEverything else makingmedicalphysics

My twenty-year-old sheet of laminated graph paper has been on my nerves as of late.  The line markings are obviously fading and getting closer together -- It's definitely not my eyesight starting to suck.

Anyhow, I went down the rabbit hole on optimizing for visibility and making the scribe marks relevant to the various checks.  This works for my eyesight and my workflow for collimator walkout, collimator accuracy and table movement etc.  The pop-up "laser blocker" has proven very satisfying (no more hunting for a random object to block the sagittal laser!)

Printing big-n-flat things can be tricky, but I've put together some notes that I hope will help.  I've included a variation that will be printable on a standard size printer bed as well as one for a larger format.  The key here is using two colors, a light color for the top face and dark for the bottom face.  Care should be taken on the color and consider using a matte filament for the top as they can be more opaque.  The top layer is only 0.6mm thick.  3D printers can be more accurate for laying down a "hole" (scribe mark) versus a color detail in a uniform plane of filament.  At least this is my observation.  I can get finer details (at least perceived?) and sharper lines by creating a hole in the top and letting the color below show through.   Consider that a 0.4mm nozzle is going to create lines that are a minimum of 0.4mm.  Whereas the same nozzle can create a "non-line" of some pretty fine detail.  The 2mm circle in the very center for collimator walkout is a good example.  .

If anyone has any "features" that they think would make this better, please share!  I'd be happy to post the .step files if you have scribe marks that work better for you.  (Not going to post the .f3d under any circumstances and make public my disaster timeline and unconstrained sketches!  - the shame!)

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Offering a few images of this process as I think that it's not being commonly used. Bolus and structures 100% generated in eclipse using smoothing / expansion / boolean tools (almost no freehand drawing)

Happy to provide more details if anyone interested (many departments don't have cerrobend in-house anymore). I've done more than I can count.

TLDR: Make a pocket structure, fill the back side of the print with craft clay so it won't deform from the heat. Chill and serve.

It's unclear how many people are still using this phantom for daily QA, but it has survived several generations of machines and does the job. If you do have one, you may have noticed that it is round and not compatible with flat surfaces. This may help.

Get it for free here! GE CT Phantom Mount.

Full collection of models here.

Description

Caveat:  This fits the GE phantoms I have rolling around my department (these have been around for several generations of scanners).  It's not clear how consistent GE was in manufacturing.  It may need slight scale adjustments in slicer to get a good fit.  

Basically snaps on the phantom (may need to do some twisting, but it should go).  Allows for attachment to an indexing bar thus speeding setup.  For me the most important daily laser check is that the side lasers are in agreement.  The "thin window" test makes visible the "opposite" laser so that you can visually check for alignment very quickly -- run the phantom in just past the isocenter.   

Includes holes for fiducials in a 10x10cm pattern.   I used 2.5mm steel BB's for a press fit, but you could also use some "Beekley Markers" and a dab of glue.    Allows for an efficient daily scale check in either X or Y direction.

Printing Notes:  PRINT FLAT ON FLAT VERTICAL SIDE (LAYING DOWN) or the snap tabs that hold it on the phantom bracket will fail.. For profile, you can use about anything.  You will need some few supports for the channel on the bottom where the index bar goes - Tree.  Much easier with a mixed material support interface if you have the capability.  4 walls, 15% infill feels about right.  Don't go with a dark color if you want to use the laser window.

If the fit just doesn't work out, I've included the .step file which should make editing easier.

I may be late to the party with some of this, but I just wanted to share some slicer settings that have changed the way I'm designing imaging cubes.

The slicer setting is "Fill multiline". It lets you create big chonky infill structures by making them arbitrarily thick -- ideal for automated image registration with CBCT.

I used to spend a lot of time creating modeled geometries to give the registration algorithm something to work with. The Fill Multiline has simplified the modeling. You do need to play with the infill pattern and possibly rotate your model on the bed to control where the lines fall to prevent a nasty line crossing in front of something you want to see on a kV or MV 2D image, but it only takes a minute. The end result are imaging cubes that automatically register perfectly with the reference CT. No manual tweaking needed even with ugly tungsten artifacts.

Anyhow, That's all! Just thought I'd share this simple tip!

And... If you're not using fuzzy skin 0.1/0.1 it will change your life.

This has been many months in the making and is punching above its weight in clinical usefulness.

You can get the model for free at this link! Foot Immobilizer on Printables

Essentially a big 3d printed foot rest that elevates the foot so that lateral (ish) fields can be used while missing the contralateral leg. It has been far superior to our previous methods (big vac bags) for positioning a foot or ankle. The therapists love the setup.

With the recent run we've seen of Benign Low Dose XRT it's been getting good use.

It does employ the existing standard U-Frame Baseplates as well as an aquaplast style mask.

If you're thinking about getting a BIG 3D printer for your department, perhaps this will push administration over the edge. It will generate a Complex Tx Device charge for the mask and you can point to that money as a way to pay for the printer in just a few uses.

It does require a printer larger than the usual 256x256mm (X1C etc). If people have a need and wish to spend department money, I have a college engineering student at home for the summer who I can put to work. He can put it up on Etsy.

Please with the feedback!

Richard Meyer