Publications by authors named "Katharina I Jerg"
Purpose: In low-dose-rate brachytherapy, iodine-125 seeds are implanted based on a treatment plan, generated with respect to different dose constraints. The quality of the dose distribution depends on a precise seed placement, however, during treatment planning the impact on the dose parameters when certain seeds fail to be placed precisely is not clear.
Methods And Materials: We developed a method using automatic differentiation to calculate gradients of dose parameters with regard to the seeds' positions.
Diffuse domain approach for flexible needle insertion and relaxation.
Int J Numer Method Biomed Eng
January 2024
Needle insertion simulations play an important role in medical training and surgical planning. Most simulations require boundary conforming meshes, while the diffuse domain approach, currently limited to stiff needles, eliminates the need for meshing geometries. In this article the diffuse domain approach for needle insertion simulations is first extended to the use of flexible needles with bevel needle tips, which are represented by an Euler-Bernoulli beam.
View Article and Find Full Text PDFPurpose: This paper presents a novel strategy for feature-based breathing-phase estimation on ultra low-dose X-ray projections for tumor motion control in radiation therapy.
Methods: Coarse-scaled Curvelet coefficients are identified as motion sensitive but noise-robust features for this purpose. For feature-based breathing-phase estimation, an ensemble strategy with two classifiers is used.
Diffuse domain method for needle insertion simulations.
Int J Numer Method Biomed Eng
September 2020
Article Synopsis
- A new needle insertion simulation strategy is introduced that eliminates the need for meshing by utilizing a diffuse domain approach on a regular grid, allowing for a more flexible representation of organ boundaries.
- The method employs a phase field function to represent transitions in tissue parameters, integrating uncertainties in volume segmentation into the simulation process.
- Results indicate that the diffuse domain approach yields deformation fields similar to those from traditional mesh simulations, enabling straightforward patient-specific simulations using automatically generated tissue probability maps from imaging data.
Purpose: During radiation therapy, a continuous internal tumor monitoring without additional imaging dose is desirable. In this study, a sequential feature-based position estimation with ultra-low-dose (ULD) kV x rays using linear-chain conditional random fields (CRFs) is performed.
Methods: Four-dimensional computed tomography (4D-CTs) of eight patients serve as a-priori information from which ULD projections are simulated using a Monte Carlo method.