Prospective Clinical Feasibility Study for MRI-Only Brain Radiotherapy

ObjectivesMRI-only radiotherapy (RT) provides a workflow to decrease the geometric uncertainty introduced by the image registration process between MRI and CT data and to streamline the RT planning. Despite the recent availability of validated synthetic CT (sCT) methods for the head region, there are no clinical implementations reported for brain tumors. Based on a preceding validation study of sCT, this study aims to investigate MRI-only brain RT through a prospective clinical feasibility study with endpoints for dosimetry and patient setup.Material and MethodsTwenty-one glioma patients were included. MRI Dixon images were used to generate sCT images using a CE-marked deep learning-based software. RT treatment plans were generated based on MRI delineated anatomical structures and sCT for absorbed dose calculations. CT scans were acquired but strictly used for sCT quality assurance (QA). Prospective QA was performed prior to MRI-only treatment approval, comparing sCT and CT image characteristics and calculated dose distributions. Additional retrospective analysis of patient positioning and dose distribution gamma evaluation was performed.ResultsTwenty out of 21 patients were treated using the MRI-only workflow. A single patient was excluded due to an MRI artifact caused by a hemostatic substance injected near the target during surgery preceding radiotherapy. All other patients fulfilled the acceptance criteria. Dose deviations in target were within ±1% for all patients in the prospective analysis. Retrospective analysis yielded gamma pass rates (2%, 2 mm) above 99%. Patient positioning using CBCT images was within ± 1 mm for registrations with sCT compared to CT.ConclusionWe report a successful clinical study of MRI-only brain radiotherapy, conducted using both prospective and retrospective analysis. Synthetic CT images generated using the CE-marked deep learning-based software were clinically robust based on endpoints for dosimetry and patient positioning.

Robotic Systems in Radiotherapy and Radiosurgery

Purpose of Review This review provides an overview of robotic systems in radiotherapy and radiosurgery, with a focus on medical devices and recently proposed research systems. We summarize the key motivation for using robotic systems and illustrate the potential advantages. Recent Findings. Robotic systems have been proposed for a variety of tasks in radiotherapy, including the positioning of beam source, patients, and imaging devices. A number of systems are cleared for use in patients, and some are widely used, particularly for beam and patient positioning. Summary The need for precise and safe delivery of focused high doses to the target region motivates the use of robots in radiotherapy. Flexibility in the arrangement of beams and the ability to compensate for target motion are key advantages of robotic systems. While robotic patient couches are widely used and robotic beam positioning is well established, brachytherapy robots are mostly considered in a research context.

Handling of Incidents in the Clinical Application of Ionizing Radiation in Diagnostic and Interventional Radiology – a Multi-center Study

Purpose According to the German legislation and regulation of radiation protection, i. e. Strahlenschutzgesetz und Strahlenschutzverordnung (StrlSchG and StrlSchV), which came into force on 31st December 2018, significant unintended or accidential exposures have to be reported to the competent authority. Furthermore, facilities have to implement measures to prevent and to recognize unintended or accidental exposures as well as to reduce their consequences. We developed a process to register incidents and tested its application in the framework of a multi-center-study. Materials and Methods Over a period of 12 months, 16 institutions for x-ray diagnostics and interventions, documented their incidents. Documentation of the incidents was conducted using the software CIRSrad, which was developed, released for testing purposes and implemented in the frame of the study. Reporting criteria of the project were selected to be more sensitive compared to the legal criteria specifying “significant incidents”. Reported incidents were evaluated after four, eight, and twelve months. Finally, all participating institutions were interviewed on their experience with the software and the correlated effort. Results The rate of reported incidents varied between institutions as well as between modalities. The majority of incidents were reported in conventional x-ray imaging, followed by computed tomography and therapeutic interventions. Incidents were attributed to several different causes, amongst others to the technical setup and patient positioning (19 %) and patient movement or insufficient cooperativeness of the patient (18 %). Most incidents were below corresponding thresholds stated in StrlSchV. The workload for documenting the incidents was rated as appropriate. Conclusion It is possible to monitor and handle incidents complient with legal requirements with an acceptable effort. The number of reported incidents can be increased by frequent trainings on the detection and the processing workflow, on the software and legal regulation as well as by a transparent error handling within the institution. Key Points: Citation Format

CT-Guided Transhepatic Catheter Drainage of Deep Postoperative Collections: Initial Experience

Introduction This article assesses the safety and utility of transhepatic drainage of deep seated postoperative intra-abdominal collections under computed tomography (CT) guidance in a short series. Materials and Methods This retrospective study included five patients (mean age: 45.8 years; 3 males, 2 females) who underwent CT-guided transhepatic drainage of postoperative abdominal abscess in our department between April 2019 and December 2020. The clinical and surgical details and the details of the transhepatic drainage procedure were evaluated along with success rates and complications. Results The surgical procedures were Whipple's pancreaticoduodenectomy in four patients and gastrectomy in one patient. Four out of five abscesses were drained through the right lobe of liver, while one was through the left lobe with a technical success rate of 100%. The mean total time for catheter drainage procedure including patient positioning and preparation was 29.2 minutes. None of the patients had procedure-related complications. Mean duration of catheter drainage was 12 days. All patients had complete resolution of symptoms after drainage and the clinical success rate was 100%. Conclusion Transhepatic approach is safe and effective for the drainage of inaccessible postoperative abdominal collections or abscesses where a standard percutaneous approach is not possible.

The Effect of Patient Positioning on Intraoperative Neuromonitoring During Thyroid and Parathyroid Surgery

Background Intraoperative neuromonitoring (IONM) has been accepted as a routine adjunct among surgeons who perform thyroid and parathyroid surgeries. Thyroid and parathyroid surgeries use various patient positioning strategies that have poorly understood effects on IONM. The aim of this study was to compare IONM signals between the transaxillary and transcervical approaches. Methods In this retrospective cohort study, we evaluated 463 adult patients who underwent a total of 502 procedures. The procedures performed included total thyroidectomy, right or left hemithyroidectomy, and parathyroidectomy. Vagus nerve and recurrent laryngeal nerve (RLN) latency and amplitude measurements were analyzed intra-operatively. The distances between the vagus nerve and the trachea were measured via ultrasound during transaxillary procedures. Results Compared to the transcervical approach, the right vagus nerve latency was significantly decreased in the transaxillary approach. Transaxillary surgery was not associated with increased latency or decreased amplitude on IONM. The distance between the vagus nerve and trachea was significantly decreased post-positioning during transaxillary approaches. Discussion Despite differences in patient positioning, a transaxillary approach was not associated with increased stress on the vagus nerve or RLN, according to IONM data. The decreased right vagus nerve latency associated with a transaxillary approach highlights the importance of considering patient positioning and laterality while interpreting IONM data.