Abstract Modern radiotherapy delivers highly conformal dose distributions to irregularly shaped target volumes while sparing the surrounding normal tissue. Due complex planning and delivery techniques, verification validation of whole treatment workflow by end-to-end tests became much more important polymer gel dosimeters are one few possibilities capture delivered distribution in 3D. The basic principles formulations dosimetry its evaluation methods described available studies validating...

Abstract Objective: This study investigates the effects of various training protocols on enhancing precision MRI-only Pseudo-CT generation for radiation treatment planning and adaptation in head & neck cancer patients. It specifically tackles challenge differentiating bone from air, a limitation that frequently results substantial deviations representation bony structures images. Approach: The included 25 patients, utilizing pre-treatment MRI-CT image pairs. Five cases were randomly...

This work presents an experimental dosimetric evaluation of raster-scanning particle beam delivery during simultaneous in-beam magnetic resonance (MR) imaging. Using open MR scanner at treatment room, radiochromic film comparisons for protons, helium and carbon ions, each with without cine imaging, yielded 2D gamma pass rates ≥ 98.8 % a 3 / 1.5 mm criterion, 99.9 5 mm. These results constitute first confirmation that time varying fields gradients do not result in clinically relevant...

For hybrid devices combining magnetic resonance (MR) imaging and a linac for radiation treatment, the isocenter accuracy as well image distortions have to be checked. This study presents new phantom investigate MR-Linacs in single measurement terms of (i) isocentricity irradiation (ii) alignment relative each other using polymer dosimetry gel (iii) 3-dimensional (3D) geometric MR distortions. The evaluation irradiated was performed immediately after with component 0.35 T MR-Linac T2-weighted...

Online adaptive treatment procedures in magnetic resonance (MR)-guided radiotherapy (MRgRT) allow compensating for inter-fractional anatomical variations the patient. Clinical implementation of these procedures, however, requires specific end-to-end tests to validate chain including imaging, planning, positioning, plan adaption and accurate dose delivery. For this purpose, a new phantom with reproducibly adjustable anthropomorphic structures has been developed. These can be filled either...

For conventional irradiation devices, the radiation isocenter accuracy is determined by star shot measurements on films. In magnetic resonance (MR)-guided radiotherapy results of this test may be altered field and need to align imaging require a modification measurement procedures. Polymer dosimetry gels (PG) offer way perform both, test, however, first it has shown that PG reveal comparable conventionally applied Therefore, were performed at linear accelerator using as well radiochromic...

Purpose. Improvements in image-guided radiotherapy (IGRT) enable accurate and precise treatment of moving tumors the abdomen while simultaneously sparing healthy tissue. However, lack validation tools for newly developed MR-guided hybrid devices such as MR-Linac is an open issue. This study presents a custom abdominal phantom with respiratory organ motion multimodal imaging contrast to perform end-to-end tests IGRT planning scenarios.Methods. The contains deformable anatomically shaped liver...

Polymer gel (PG) dosimetry enables three dimensional (3D) measurement of complex dose distributions. However, PGs are strongly reactive with oxygen and other contaminations, limiting their applicability by the need to use specific container materials. We investigate different 3D printing materials techniques for compatibility PG. Suitable may provide possibility perform PG in complex-shaped phantoms. printed PG-filled test vials were irradiated homogenously. The signal response was evaluated...

Objective.In MR-guided radiotherapy (MRgRT) for prostate cancer treatments inter-fractional anatomy changes such as bladder and rectum fillings may be corrected by an online adaption of the treatment plan. To clinically implement complex procedures, however, specific end-to-end tests are required that able to validate overall accuracy all steps from pre-treatment imaging dose delivery.Approach.In this study, test a fractionated adapted MRgRT irradiation was performed using so-called...

To describe performance measurements, adaptations and time stability over 20 months of a diagnostic MR scanner for integration into MR-guided photon particle radiotherapy.For realization therapy (MRgRT/MRgPT), 1.5 T was installed at the Heidelberg Ion Beam Therapy Center. integrate MRI treatment process, flat tabletop dedicated coil holders flex coils were used, which prevent deformation patient external contour allow use immobilization tools reproducible positioning. The signal-to-noise...

Abstract Objective. Magnetic resonance (MR) images free of artefacts are pivotal importance for MR-guided ion radiotherapy. This study investigates MR image quality simultaneous irradiation in an experimental setup using phantom imaging as well in-vivo imaging. Observed described within the and their cause is investigated with goal to find conclusions solutions potential future hybrid devices. Approach. An open scanner a field strength 0.25 T has been installed front beamline. Simultaneous...

Abstract As magnetic resonance-guided radiotherapy (MRgRT) is becoming increasingly important in clinical applications, the development of new quality assurance (QA) methods needed. One aspect alignment radiation and imaging isocenter. MR-visible polymer gels offer a way to perform such measurements online additionally may allow for 3-dimensional (3D) evaluation. We present star shot measurement irradiated scanned with 0.35 T MR-LINAC device evaluating polyacrylamide gelatin (PAGAT) gel...

Quality assurance in magnetic resonance (MR)-guided radiotherapy lacks anthropomorphic phantoms that represent tissue-equivalent imaging contrast both computed tomography (CT) and MR imaging. In this study, we developed phantom materials with individually adjustable CT value as well [Formula: see text]- text]-relaxation times at three different field strengths. Additionally, their experimental stopping power ratio (SPR) for carbon ions was compared predictions based on single- dual-energy...

Abstract The implementation of new image-guided radiotherapy (IGRT) treatment techniques requires the development quality assurance (QA) methods including geometric and dosimetric validation applied dose in 3D. Polymer gels (PG) provide a promising tool to perform such tests. However, be used large variety clinical applications, PG must flexibly applicable. In this work, we present phantoms routine both hardware workflow tests IGRT. This includes isocenter accuracy magnetic resonance...

Polymer gel (PG) dosimetry is a valuable tool to measure complex dose distributions in 3D with high spatial resolution. However, due protocols that need be followed for in-house produced PGs and the costs of commercially available gels, PG gels are only rarely applied quality assurance procedures worldwide. In this work, we provide an introduction perform highly standardized dosimetric experiments using PAGAT (PolyAcrylamide Gelatine fabricated at ATmospheric conditions) gel. can atmospheric...

This study investigates the LET-dependence of dose measurements performed with a nanocomposite Fricke gel (NC-FG) upon irradiation carbon ion beams to address problem quenching dosimeters in high-LET particle therapy. The preparation NC-FG simple device was for atmospheric and anoxic environmental conditions two different container materials. Irradiation at energies 133.39 MeV/u or 194.87 MeV/u, complemented by modulated 10 mm spread-out Bragg peak (SOBP) irradiation. R1 profiles obtained...

Abstract Background Particle therapy makes a noteworthy contribution in the treatment of tumor diseases. In order to be able irradiate from different angles, usually expensive, complex and large gantries are used. Instead rotating beam via gantry, patient itself might rotated. Here we present tolerance compliance volunteers for fully-enclosed rotation system clinical magnetic resonance (MR)-scanner potential use MR-guided radiotherapy, conducted within prospective evaluation study. Methods A...

Background and PurposeMagnetic Resonance Imaging (MRI) is widely used in oncology for tumor staging, treatment response assessment, radiation therapy (RT) planning. This study proposes a framework automatic optimization of MRI sequences based on pulse sequence parameter sets (SPS) that are directly applied the scanner, application RT planning.Materials MethodsA phantom with 7 in-house fabricated contrasts was measurements. The proposed employed derivative-free algorithm to repeatedly update...

<title>Abstract</title> Background Particle therapy makes a noteworthy contribution in the treatment of tumor diseases. In order to be able irradiate from different angles, usually expensive, complex and large gantries are used. Instead rotating beam via gantry, patient itself might rotated. Here we present tolerance compliance volunteers for fully-enclosed rotation system clinical magnetic resonance (MR)-scanner potential use MR-guided radiotherapy, conducted within prospective evaluation...