ESTRO 2024 - Abstract Book

S4909

Physics - Quality assurance and auditing

ESTRO 2024

Conclusion:

We have shown that it is possible to perform patient QA by faithfully tracking the actual trajectory with high accuracy using conventionally used radiochromic film, ionization chamber, and 4D-moving phantom. We also detected a decrease in the pass rate in cases where it was challenging to construct a correlation model, such as when the travel distance was considerable.

Keywords: Synchrony, breath tracking, 3-axis moving phantom

References:

1 ） Ferrisx WS, Culberson WS, Smilowitz JB, et al., Effects of variable-width jaw motion on beam characteristics for Radixact Synchrony, J. Appl. Clin. Medical Phys., 22(5), 175-181, 2020

2 ） Ferris WS, Kissick MW, Bayouth JE, et al., Evaluation of radixact motion synchrony for 3D respiratory motion: Modeling accuracy and dosimetric, fidelity J. Appl. Clin. Medical Phys., 21(9), 96-106, 2020

2572

Digital Poster

Clinical Experience in Patient-Specific QA for Prostate MRI-Only Workflow

Marco Fusella, Mattia Nicoletto, Marco Ciro Schifano, Erick Maffi, Davide Fiorentin, Alessandro Testolin, Fabio Busato

Abano Terme Hospital, Department of Radiation Oncology, Abano Terme (PD), Italy

Purpose/Objective:

The integration of MRI into radiation therapy has greatly improved the accuracy of treatment. However, the combined use of CT and MRI can introduce geometric discrepancies related to variations in location, anatomical correspondence, and image registration. MRI-derived synthetic CT (sCT) images have the potential to eliminate these inaccuracies, easing the burden of multiple image sets. Adoption of sCT algorithms could revolutionize clinical practice for MRIgRT therapy users, extending the benefits to C-arm linac users transitioning to an MRI-only workflow. The main challenge preventing the implementation of sCT lies in the lack of consensus on commissioning and quality assurance (QA) protocols. In this study, we present our institution's workflow and share the results of one year of clinical practice.

Material/Methods:

In the past year, our center treated 85 patients with MR-only radiation therapy for prostate cancer. A total of 120 MR and sCT images were collected, including those used for replanning and/or adaptive. All patients received MR planning