Tongue cancer is a form of oral cancer. By treating tongue cancer, a piece of the tongue holding the tumour is cut away. Extra tissue around the tumour is removed to assure that no cancer cells are left behind. removing excess tissue affects oral functions like chewing, swallowing and speech badly. Therefore, the extra tissue cut away around the tumour is minimised. After the treatment, the specimen of the tongue is scanned with ultrasound (US) to assure that the whole tumour is removed. On the scan, the thickness of the tissue between the tumour and cutting surface is measured, called the resection margin. About 10 mm of space between tumour and cutting surface is considered "safe". When the tumour is closer to the cutting surface, the risk that some cancer cells are left in the patient its tongue is too high and the surgeon may decide to cut away more tissue from the tongue.
To measure the tongue specimen, a clinician moves the acoustic transducer over the tongue specimen by hand. A 2D image on the US scanner shows a cross-section of the tongue specimen. The clinician measured the distance from the tumour to the cutting surface on that 2D image. This makes the measurement process prone to human errors. Making a 3D reconstruction of the tongue specimen can be much more useful for this kind of measurements. There are already tools to use a US scanner with an electromagnetic pose-tracking system to generate 3D reconstructions. The clinician still has to move the acoustic probe manually in all six dimensions, position and orientation. Generating a 3D reconstruction based on cross-sections that are translated and rotated with respect to each other involves lots of interpolation, which can introduce errors and information may be lost.
This assignment involves designing a setup to automatically translate the acoustic transducer over tongue specimen. The setup needs to move the acoustic transducer in a single dimension only to be able to generate a fully digital 3D reconstruction of the tongue specimen by stacking the 2D images generated by the US scanner. No interpolation needs to be done. Accurate measurements can be done on that digital 3D reconstruction.
Validation is done using artificial phantoms, holding tumours of predefined shapes. These phantoms are scanned using the existing manual scanning method as well as with the new controlled scanning method. The resulting 3D reconstructions can be compared to measure the improvement of the new scanning method.