ESTRO 2022 - Abstract Book

S272

Abstract book

ESTRO 2022

analysis, five key themes that highlighted the patient experience were identified: ‘patient education’, ‘organization’, ‘patient centered care’, ‘attitude of care providers’ and ‘general impression’. These were translated into action points for improvement. Concerning patient education, it appeared that the given information was not always received properly by the patients (only 42% indicated to have received all the information about the type of cancer, the specific treatment and general care). Furthermore, patient education and some organizational aspects of the RO department like ensuring care continuity during follow-up consultations were considered as challenges for future improvement. Regarding the evaluation of the compatibility of both questionnaire, a significant association between the overall rating in SQ and the overall rating in LQ was found. However the single use of a SQ could have been too narrow to formulate specific action points. Therefore the SQ is seen as an add-on rather than a replacement of LQ. Conclusion The implementation of PREM at the RO department was feasible. Specific action points were framed for future improvements of the department. A mixed-method design, by integrating qualitative and quantitative data, in PREM-studies should not be overlooked. S. Verheijen 1 , R. de Moes 2 , M.A. Palacios 2 , C.J. Haasbeek 2 , F.L. Schneiders 2 , A.M. Bruynzeel 2 , B.J. Slotman 2 , F.J. Lagerwaard 2 , S. Senan 2 1 Amsterdam UMC, VUmc location, de Boelelaan 1117, 1081 HV Amsterdam, Department of Radiation Oncology, Amsterdam, The Netherlands; 2 Amsterdam UMC, location VUmc, de Boelelaan 1117, 1081 HV Amsterdam, Department of Radiation Oncology, Amsterdam, The Netherlands Purpose or Objective Single fraction SBRT is a standard treatment option for lung malignancies. We report on the workflow and patient satisfaction for a one stop shop (OSS) service for delivery of MR-guided SBRT in lung tumors. Materials and Methods Suitable patients were identified by a radiation oncologist before consultation. Eligibility criteria were tumor size <5cm, located >1 cm from critical structures, and tumor visibility on both a 3D MR scan and MR-cine acquisitions. The workflow consisted of consultation, simulation, treatment planning and delivery. The duration of each step was monitored. After SBRT, patients completed a questionnaire to assess their overall impression with the OSS procedure and waiting times between workflow steps. A dedicated MR-simulation session assessed tumor mobility in 3 planes, in combination with a 3D MR scan in breath-hold, followed by a breath-hold CT scan for dose calculation purposes. IMRT step-and-shoot plans were generated, using typically 12 beams and 25 segments. The prescribed dose was either 30 or 34Gy to the PTV, in accordance with NRG-RTOG 0915 trial constraints. In a second phase of the OSS procedure, autocontouring of OARs was implemented in combination with the use of a patient-specific template for dose optimization derived from a preplanning on a diagnostic CT. SBRT was delivered on an MR-linac, with breath-hold gating performed using visual feedback of real-time tumor tracking on a video screen. Online plan-adaptation enabled two consecutive sessions, allowing patients to rest during treatment, thus increasing gating efficiency. Results Seven patients underwent the OSS procedure. All treatment plans fulfilled institutional dose constraints. Figure 1A shows the time spent by a patient in each workflow step. Total procedure time decreased from on average 7.5h for the first 5 patients, to 4h for latter patients. Simulation took 45 min on average. Treatment planning times decreased from 4.0h to 1.2h after implementation of auto contouring of organs at risk and the use of patient-specific templates. Full breath-hold delivery and re-optimization took on average 1.3hrs. MO-0311 One stop shop single fraction MR-guided stereotactic radiotherapy: Workflow and patient satisfaction

Figure 1B summarizes findings from patient questionnaires completed at the end of the OSS treatment. All patients were pleased with the opportunity to complete pre-treatment imaging and treatment in one single day. However, some regarded