Injectable Tumor Phantoms
Michael Sramek | Yuan Shi | Erick Quintanilla | Xiaotian Wu PhD | Aravind Ponukumati
Overview Video
Overview Video
If using or refining this methodology, please cite these articles:
Tumor phantom for training and research in transoral surgery (Investigative Otolaryngology)
Development of a novel tumor phantom model for head and neck squamous cell carcinoma and its applications (SPIE Digital Library)
Syringe Adaptor Download
3D-Printable Syringe Adaptor
Download 3D Printable Syringe Adaptor
A 3D-printable syringe adaptor designed in Solidworks as two separate files .
Click on the images (yellow) to download 3D-Printable .Stl files
Printing Recommendations
For printing the syringe adaptor, it is recommended to use a high-resolution, resin, 3D printer. We employed a Formlabs Form 2 SLA printer with durable resin. The orientation below allows the optimization of the Luer Lock threads during printing. Our print was at a resolution of 50 microns and took approximately 20 hours to complete. Images below were generated with the Pre-form software prior to printing.
Front View
Side View
Back View
Materials and Methods
Preparation of Tumor Phantom
Materials
Table 1 lists the ingredients with measured quantity to prepare the tumor phantom.
Tumor Phantom Preparation
The flowchart and text below give a step-by-step instruction on how to prepare and inject the tumor phantom with the syringe adaptor.
Step 1: Prepare Ingredients
Dilute iohexol in DI water by a 1:7-7.5 ratio* measured in mL
Dilute 25% glutaraldehyde in DI water to 4%
Step 2: Making Tumor Phantom Base Solution
Weigh 0.6 g agar and 2.4 g gelatin
Measure and combine 30 mL chicken stock and 30 mL DI water
Add agar and gelatin in the mixture
Add 4 drops of food coloring in the mixture*
Stir the mixture vigorously until uniform color and texture
Heat the mixture until boiling
Add diluted iohexol to heated solution and mix vigorously
Maintain it at 45-50ºC until ready to mix with the glutaraldehyde
Step 3: Load Materials for Injection
Draw up 10 mL base solution in a 10 mL syringe and attach to syringe adaptor
Draw up 1 mL glutaraldehyde in a 1 mL syringe and attach to syringe adaptor
Finish assembly with connection of the plunger
Assemble a needle if needed (17G spinal needle is used for cadaver injections)
Step 4: Inject into Cadaver (or other non-living tissue model)
Slowly depress the master plunger and apply uniform pressure on both syringes
Prime the syringe adaptor before injection to remove air
Inject!!!
Rinse the syringe adaptor with water promptly after the injection to avoid clogging the mixing channel
* The ratio of food coloring and iohexol could be adjusted as needed to affect tumor appearance and enhancement on imaging, respectively.
Warning: Glutaraldehyde safety data sheet can be found here
Injection Technique
It is recommended that a constant low but even pressure be applied to the plunger during injection of tumor phantoms. This is to prevent intra-barrel solidification; however, too much pressure will cause hydrodissection.
Prime the barrel so a few drops of TP is seen flowing out of the needle.
Insert into the submucosa and advance ~5mm.
Slowly, putting even pressure on the plunger, inject tumor phantom material until the desired morphological change is observed.
Withdraw the injector but keeping even pressure on the plunger to prevent blockage of the barrel.
Rinse the barrel with an extra 10mL syringe filled with water attached to the location where the base was previously.
Prepare for the next injection.
A. Assembled syringe adaptor post injection. B. Injection of cadaver head utilizing suspension laryngoscopy. C. Tonsil prior to injection. D. Tonsil during injection. E. Tonsil post injection.
Modeling in Cadaver
Access location with Lindholm laryngoscope or oral retractor. Follow the steps of the injection technique.
Examples of injections in various sub-sites
Special Considerations
Storage of specimens:
Notably, the specimens appeared well after freeze-thaw cycle however there was a significant loss of radiodensity.
We recommend, if you plan to use imaging as part of your training regimen to image the same day of injection or store in a morgue or refrigerator to limit radiographic loss.
Below: before and after freeze-thaw of tonsillar injection.
Contact us with questions:
Please contact Mike for further information or questions.
