Chair for Computer Aided Medical Procedures & Augmented Reality
Lehrstuhl für Informatikanwendungen in der Medizin & Augmented Reality

Master thesis

Title: Navigated Biopsy of scintigraphic cold nodules for patients suspected of having thyroid cancer
Abstract: Thyroid nodules a are very common clinical finding. Both physicians and surgeons are often asked to make a diagnostic decision or a management recommendation. In the thyroid diagnosis field, a scan of the functionality of the thyroid by using the radioactive isotope of iodine or technetium is generally available and standard technique in Nuclear Medicine. Such examination, commonly known as thyroid scintigraphy, enables the doctor to detect areas where an hyperfunction (hot areas) of the thyroid or an hypofunction (cold areas) are present. Nodules on the scan are classified according to their ability to take up the isotope. Almost all hot nodules are possibly benign tumors which can be treated with a radioiodine therapy, while cold nodules may be malignant tumors which have to be removed surgically.
At the moment, pictures of the metabolic activity of the thyroid are normally acquired, with using small gamma-ray cameras. While the taken images are usually "precise enough" for examinations, they only offer a two-dimensional view. The intraoperative technology of freehand SPECT makes possible to generate a three-dimensional view of the radioactive uptake by using an optically tracked gamma probe. Using this technology , extended by an ultrasound (US) probe, it is possible to distinguish between nodules with different uptake which are layered on top of each other. Furthermore in some cases, even if the doctor recognized the nodules, it is hard for him/her to figure out which was the cold nodule and which was the hot nodule in the US image. In fact, this is a very important information, as it is recommended to perform a biopsy of cold nodules to check whether they are malignant tumors.
In general, ultrasound guidance for such interventions is difficult to learn and perform. In a needle biopsy, the needle must be inserted into an anatomical target to remove a sample of tissue. The challenge here is to reduce the number of needle insertions by accurately inserting the needle into the target. In some cases, the collected material does not contain thyroid cells, or they contain too little to say, whether it is cancer, whether it is missing. It has the place in 30% of the cases in thyroid biopsy. To solve this problem biopsy is repeated, sometimes, if other cancer symptoms are present, the patient is operated in spite of deficiency in recognition of the malignant process in the biopsies.
To make biopsy procedures more accurately and certain we propose to visualize the scintigraphic information and the conventional needle on the ultrasound image. We believe that our system would help to precisely guide the needle to the target point (for example cold nodules) and thus to minimize the number of needle insertions as well as guarantee a secure diagnose. A successful needle biopsy could mean avoiding open surgical biopsy, which may require general anesthesia, hospitalization and a longer recovery period, beyond side effects and unnecessary danger. In this thesis presented an extension of the existing system combining the ultrasound with freehand SPECT technology of a biopsy needle guidance.
Student: Katarzyna Szajkowska
Director: Nassir Navab
Supervisor: Thomas Wendler
Type: Master Thesis
Area: Medical Imaging, Molecular Imaging, Computer-Aided Surgery, Medical Augmented Reality
Status: finished
Start: 2008/08/01
Finish: 2009/09/31

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