Unlikely bedfellows are harmonizing to reproduce one of the world?s most famous musical instruments. A radiologist and two violin makers worked together to duplicate a Stradivarius. Even if you can’t pronounce it, much less spell it, most people know of this rare instrument that started making beautiful music in 1704.

The team used a CAT (computerized axial tomography) or CT scan to produce over 1,000 images to measure the density of the wood, the size, shape, thickness, and volume of the violin. CT DICOM (Digital Imaging and Communication in Medicine) is the industry standard for transferring radiologic images and other medical information between computers.
 
In this case, the DICOM files were run through OsiriX image processing software to transform them into stl files, a software format used in Stereolithography to create 3D models. Those files were imported into a CNC (computer numerically controlled) routing machine capable of 3D precision carving.

The CNC, using Rhinoceros CAD software, made nearly exact copies carving the back plates from maple and the front plates from spruce with maple scrolls. Shape, arching and quality of the wood contributes to a violin?s sound. It is also thought that the unique red varnish Stradivari used enhances the vibrational quality of the wood, whereas other coatings can reduce or eliminate the vibration.

The scientific paper was presented at RSNA 2011, the Radiological Society of North America?s Scientific Assembly and General Meeting which runs from Nov 27 – Dec 2. Steven Sirr, M.D., a radiologist at FirstLight Medical Systems in Mora, Minnesota said: "CT scanning offers a unique method of noninvasively imaging a historical object." He worked with professional luthiers John Waddle and Steve Rossow of St. Paul, Minnesota.

Side-by-Side Comparison of Original Stradivarius and Duplicate

Side-by-Side Comparison of Original Stradivarius and Duplicate

The "Betts" Stradivarius, as the one used for the project is called, is one of about 650 in existence that were built by the Italian Antonio Stradivari. The famous violin is held in the United States Library of Congress. Other models have been sold at Christie?s auctions for over $3.5 million dollars. Its design, craftsmanship, appearance, and of course sound, makes a Stradivarius so valuable.

Violins can range in size from 1/16 for children three to five years old with an arm length of 14 inches to a full size for adults or older children with an average arm length of 23 inches. In all, there are seven sizes to choose from. The new reproductive procedure should make high quality instruments within reach of more aspiring musicians.