Biomedical subjects

Thomas Böttger

Publications and source records attributed to Thomas Böttger.

3 recordsLinked to original sources

PubMed2005

The medical imaging interaction toolkit.

Thoroughly designed, open-source toolkits emerge to boost progress in medical imaging. The Insight Toolkit (ITK) provides this for the algorithmic scope of medical imaging, especially for segmentation and registration. But medical imaging algorithms have to be clinically applied to be useful, which additionally requires visualization and interaction. The Visualization Toolkit (VTK) has powerful visualization capabilities, but only low-level support for interaction. In this paper, we present the Medical Imaging Interaction Toolkit (MITK). The goal of MITK is to significantly reduce the effort required to construct specifically tailored, interactive applications for medical image analysis. MITK allows an easy combination of algorithms developed by ITK with visualizations created by VTK and extends these two toolkits with those features, which are outside the scope of both. MITK adds support for complex interactions with multiple states as well as undo-capabilities, a very important prerequisite for convenient user interfaces. Furthermore, MITK facilitates the realization of multiple, different views of the same data (as a multiplanar reconstruction and a 3D rendering) and supports the visualization of 3D+t data, whereas VTK is only designed to create one kind of view of 2D or 3D data. MITK reuses virtually everything from ITK and VTK. Thus, it is not at all a competitor to ITK or VTK, but an extension, which eases the combination of both and adds the features required for interactive, convenient to use medical imaging software. MITK is an open-source project (www.mitk.org).

Algorithms↗

PubMed2003

Programmable laser frequency stabilization at 1523 nm by use of persistent spectral hole burning.

Diode laser frequency stability of 2 kHz to 680 Hz over 20 ms to 500 s has been demonstrated at 1523 nm in the technologically important communication band by use of persistent spectral holes in the inhomogeneously broadened 4I15/2 --> 4I13/2 optical absorption of Er3+:D-:CaF2. Laser frequency stabilization was realized without vibrational or acoustical isolation of either the laser or spectral hole frequency reference, providing the means for implementing a versatile, compact, stable source.

Journal Article↗

PubMedDate not supplied

How many lymph nodes are needed for an accurate pN classification in esophageal cancer? Evidence for a new threshold value.

BACKGROUND/AIMS: The UICC recommends a number of at least six lymph nodes to be examined in the surgical therapy of esophageal cancer for a reliable pN classification. The aim of this study was to evaluate this threshold by means of the data from our patients. METHODOLOGY: Following curative resection (R0) of esophageal cancer the numbers of examined tumor-free and tumor-involved lymph nodes were compared. Different statistical models of logistic regression were fitted to the data and checked for plausibility (Hosmer Lemeshow test). The sensitivity of a correct pN classification was then calculated and correlated to the total number of examined lymph nodes. RESULTS: A maximum increase of the sensitivity in classifying pN occurred from 0 to 6 examined lymph nodes. Nevertheless an additional improvement of sensitivity was continuously shown up to 100 examined nodes. An over 90% sensitivity of a correct lymph node classification was reached when more than twelve nodes were examined. Thus the results demonstrate in the case of esophageal cancer, that the suggestion by the UICC to examine at least 6 nodes for defining pN appears too low and may not represent the clinical situation. A ninety percent confidence level of a correct lymph node classification can be expected above 12 examined nodes similarly to the current recommended threshold in colorectal carcinoma. CONCLUSIONS: We suggest a new threshold for the number of examined lymph nodes of at least 12 instead of 6 nodes for accurately defining the pN category in esophageal cancer.

Abdomen↗