Spectral imaging reveals surprisingly much about dental health

Spectral imaging is undergoing rapid development. With a well-optimised microscope, camera, lighting and data management in particular, imaging can be utilised in many ways, for example when analysing the effects of radiation therapy on the jaw bone and teeth.

Constituting part of the Innovative Cities programme of the Finnish Funding Agency for Innovation, Tekes, the CSIBIOMED project was recently completed at the University of Eastern Finland. Besides various units from the university, the project also had industrial partners such as Planmeca, Olapcon (Arcusys) and Olympus. Carried out at SIB Labs, the project was a shared effort involving many units.

Despite its short duration, much was achieved in the project: researchers carried out device and prototype development, tools for data management and analysis were created, and even a completely new file format was developed for research use.

“The TIFF-based image format now supports image preview on Windows Photo Viewer, for example, and meta data can also be added to the files. And what’s best, all data can now be saved in a single file,” said Postdoctoral Researcher Pauli Fält at the project's closing seminar in Kuopio.

“Our spectral image database now enables extensive searches. We’ve also done some microscope modification for spectral and fluorescence imaging. Moreover, Olympus from Japan let us borrow their special microscope.”

An external light source was attached to the microscope, allowing researchers to alter the wavelength of light and, for example, produce UV radiation. Images were taken on different cameras, including an RGB camera. It takes about one minute to take one image, because the camera captures the target one channel at a time.

“Here in Kuopio, we focused on the effects of radiation therapy on human teeth and jaw bone, among other things. This is a very hot theme of research at the moment, and there isn’t much research evidence on the topic,” Fält said.

With spectral imaging, dental samples can be analysed for caries and changes in the dental structure in a completely new way, among other things.

“The objective is to identify the optimal wavelengths, after which we can start developing an optimised light source and camera to find the best solutions in terms of imaging costs and speed,” said Professor Markku Hauta-Kasari, the Head of the School of Computing.

“Spectral imaging can also be used in the field of plant biology, for example when studying environmental stress.”


Spectral imaging – a tool for future clinical research

The project’s industrial partners, Planmeca, Olapcon and Olympus, are pleased with the results achieved.

“Multi-spectral imaging is expected to become a key technology in the development of sensor networks for big data analysis. This project has provided us with information about the basic technology and parameter usability, and we can use this information in our own product development,” said Dr Susumu Kikuchi from Olympus.

“Open-minded thinking will play a crucial role in product development in the future.”

For Planmeca's Vice President of Research and Technology Vesa Varjonen, the year in spectral imaging research has been an interesting one.

“I want to work close to the markets. There is a strong interest in spectral imaging, because it will change the world and especially the role of current X-ray imaging,” Varjonen said.

“We hope to continue doing research with the University of Eastern Finland.”

“This project has provided a completely new perspective into oral diagnostics,” said Docent Arja Kullaa from the Institute of Dentistry of the University of Eastern Finland.

“We have now taken a major step towards practical work. Spectral imaging is a new tool, and we will keep developing it in order to find clinical applications.”

Text: Marianne Mustonen
Photo: Raija Törrönen