A Personalized 3D-Printed Model for Preoperative Evaluation in Thyroid Surgery

In this study, we aim to improve the preoperative assessment, patient communication, and the surgical certainty of thyroid surgery through personalized 3D thyroid models. This technique can very valiantly restore the relationship between the thyroid gland and the surrounding structures using less time and cost. If we can obtain high precision 3D images or personalized 3D model can be met.

For example, liver surgery. To begin scan the patient's thyroid by enhanced computerized tomography to obtain the image data in DICOM format. Import the scanned image data into the software and set the appropriate threshold according to the difference in gray value between the thyroid gland and surrounding tissues or organs.

As different gray values reflect differences in the intensity of different areas of the human body, set the gray scale threshold to 226 to 1500 to present the bone image, set the threshold to minus 200 to 226 to show the thyroid gland image. Let the software automatically identify the boxed area or manually outline the boundary of the target area if the recognition is not satisfactory. Generate STL files from the reconstructed data model.

After getting the doctor's approval on the reconstructed 3D model, transfer the STL file data to the colorful material 3D printer to set the parameter presets through the supporting 3D printing slicing software. Select the printing model according to the type of finished products. Color printing models usually use white jet process technology.

While photosensitive resin uses digital light procession. Select the slice stroke thickness parameter according to the thickness of the products. Here, 23 to 36 micrometers.

Choose the support method according to the fineness of the printing model either overall support for better protection and less damage to fine details or partial support which saves materials. Then select model coloring using the color palette function on the printer. Unify the arteries with red color 255 and the veins with blue color 255.

Fill in hard light curing resin in the 3D printer. Debug the printing platform and print using white jet process technology. After printing, take out the preliminary printed thyroid model.

Subtract the supporting structure by breaking apart and wrapping supports around the preliminary model with gloved hands and remove most of the main body of the supporting structure. Put the model into an ultrasonic cleaner with calcium hydroxide alkaline solution for a 15-minute cleaning. Put the model into a wet sandblaster and rinse it until the rest of the support structure on the surface is washed away.

Next, grind the model with an electric grinder file or grinding wheel. After grinding, spray the varnish into large area color blocks on half of the model's surface. Then manually paint the small area color blocks with varnish.

Next, put the model into a UV curing machine for 30 seconds of curing. Then take out the model and clean it with 95%alcohol. Pack the finished thyroid model and complete the delivery to the surgeons before surgery.

Following this approach, a complete 3D printed model of the thyroid region was constructed through enhanced computerized tomography before the operation for a thyroid cancer patient. High quality 3D images is a basis for printing. The WGP printing technology is a key point to high quality 3D models.