A random walk model for intra-fraction motion has been proposed, where at each step the prostate moves a small amount from its current position in direction. Online tracking data perineal ultrasound is used to validate or reject this against alternatives. Intra-fraction of was recorded by 4D (Elekta Clarity system) during 84 fractions external beam radiotherapy six patients. In total, center tracked 8 h intervals 4 s. Maximum likelihood parameters were fitted data. The null hypothesis tested...

To report our results with postoperative or definitive radiation therapy in head and neck sarcomas. We performed a retrospective analysis of 26 patients suffering from sarcomas, who received between 2003 2012. Median age was 64 years (19–88) 69 % were male. Tumor locations skull (including skin) 31 %, paranasal sinus/orbita 27 pharynx/larynx) 42 %. tumor size 4.6 cm (1-12 cm). 22 (85 %) presented primary situation. Stage at presentation (UICC 7th for soft tissue sarcomas) as follows: Ia:4...

The accuracy of the Elekta Clarity™ three-dimensional ultrasound system (3DUS) was assessed for prostate positioning and compared to seed- bone-based in kilo-voltage cone-beam computed tomography (CBCT) during a definitive radiotherapy. 6 patients, with fiducial markers implanted into prostate, controlled by 3DUS CBCT. In total, 78 scans were performed trans-abdominally bone-matches seed-matches CBCT scans. Setup errors detected different modalities compared. Systematic random analysed,...

Metal implants, surgical clips and other foreign bodies may cause 'streaking' or 'star' artifacts in computed tomography (CT) reconstructions, for example the vicinity of dental restorations hip implants. The deteriorated image quality complicates contouring has an adverse effect on quantitative planning external beam therapy.The potential to reduce by acquisition tilted CT reconstructions from different angles same object was investigated. While each those still contained artifacts, they...

The purpose of this paper is to understand intrafraction movement as a stochastic process driven by random external forces. hypothetically proposed three-dimensional walk model has significant impact on optimal PTV margins and offers quantitatively correct explanation experimental findings. Properties the are calculated from first principles, in particular fraction-average population density distributions for displacements along principal axes. When substituted into established margin...

To identify the relevant technical sources of error a system based on three-dimensional ultrasound (3D US) for patient positioning in external beam radiotherapy. quantify these controlled laboratory setting. estimate resulting end-to-end geometric precision intramodality protocol.Two identical free-hand 3D US systems at both planning-CT and treatment room were calibrated to frame reference. Every step calibration chain was repeated multiple times its contribution overall systematic random...

To assess the accuracy and precision of a fully integrated pilot installation stereoscopic X-ray imaging kV-CBCT for automatic couch positioning in stereotactic radiotherapy intracranial tumors. Positioning errors as detected by are compared to those (i.e. new method is verified established method), repeated images determined intra-modally).Preliminary results reported from study with 32 patients Patients were treated guided kV-CBCT. Patient was automatically corrected robotic couch....

Introduction: Secure Multi-Party Computation (SMPC) offers a powerful tool for collaborative healthcare research while preserving patient data privacy. State of the art: However, existing SMPC frameworks often require separate executions each desired computation and measurement period, limiting user flexibility. Concept. This explores potential client-driven metaprotocol Federated Computing (FSC) framework its SImple Multiparty ComputatiON (SIMON) protocol as step towards more flexible...

Abstract Background This long-term retrospective analysis aimed to investigate the outcome and toxicity profile of stereotactic brachytherapy (SBT) in selected low-grade gliomas WHO grade II (LGGII) a large patient series. Methods comprised 106 consecutive patients who received SBT with temporary Iodine-125 seeds for histologically verified LGGII at University Munich between March 1997 July 2011. Investigation included clinical characteristics, technical aspects SBT, application other...

Infra-fraction motion of the prostate was recorded during 2.385 fractions image guided radiotherapy (IGRT) in 126 patients, 14 which were treated by intensity modulated radiation therapy (IMRT), and 112 volumetric arc (VMAT). The imaged three-dimensional time-resolved transperineal ultrasound (4D-US) type Clarity Elekta, Stockholm, Sweden. volume registered position (center volume) at a frequency 2.0 samples per second. This raw data set contains total 1.138.024 patient couch positions over...

Privacy-preserving computation (PPC) enables encrypted of private data. While advantageous in theory, the complex technology has steep barriers to entry practice. Here, we derive design goals and principles for a middleware that encapsulates demanding cryptography server side provides simple-to-use interface client-side application developers. The resulting architecture, “Federated Secure Computing”, offloads computing-intensive tasks separates concerns business logic. It microservices...

Intrafraction motion is particularly problematic in case of small target volumes and narrow margins. Here we simulate the dose coverage intraprostatic lesions (IPL) by simultaneous integrated boosts (SIB). For this purpose, use a large sample actual intrafraction data. Fifty-three h intra-fraction prostate were recorded real-time 4D ultrasound (4DUS) during 720 fractions 28 patients. We spherical IPLs with 3, 5, 7 mm radius matching SIBs 0, 2, 5 safety The volumetric overlap between...

Background Patient data is considered particularly sensitive personal data. Privacy regulations strictly govern the use of patient and restrict their exchange. However, medical research can benefit from multicentric studies in which different institutions are pooled evaluated together. Thus, goals utilization protection conflict. Secure multiparty computation (SMPC) solves this conflict because it allows direct on distributed proprietary data—held by owners—in a secure way without exchanging...

Three-dimensional ultrasound (3D-US) is used in planning and treatment during external beam radiotherapy. The accuracy of the technique depends not only on achievable image quality clinical routine, but also technical limitations precision calibration. Refraction waves a known source for geometric distortion, such an effect was expected homogenous calibration phantoms. However, this paper we demonstrate that discontinuity refraction index at phantom surface may affect unless probe perfectly...

During a fraction of external beam radiotherapy for prostate cancer, mismatch between target volume and dose coverage may accumulate over time due to intra-fraction motion. One way remove the residual error is perform couch shift in opposite direction. In principle, such shifts could cause secondary displacements patient prostate. Hence it interesting investigate if might amplify Intra-fraction motion position were simultaneously recorded during 359 fractions 15 patients. this time, total 22...

Infra-fraction motion of the prostate was recorded during 3.423 fractions image guided radiotherapy (IGRT) in 191 patients, 14 which were treated by intensity modulated radiation therapy (IMRT), and 177 volumetric arc (VMAT). The imaged three-dimensional time-resolved transperineal ultrasound (4D-US) type Clarity Elekta AB, Stockholm, Sweden. volume registered position (center volume) at a frequency 2.0 samples per second. This raw data set contains total 1.985.392 patient couch positions...

In Secure Multiparty Computation (MPC or SMPC), functions are evaluated in encrypted peer-to-peer networks without revealing the private inputs of participating parties. The median is a non-trivial computation MPC and particularly relevant fields like medicine economics. Here, we provide an implementation for Federated Computing (FSC) framework. It tested on synthetic datasets with varying sizes (N=102 to N=107) number participants (M=2 M=10) across different network environments hardware...